Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name. The relevant selftests have also been updated to assert that `name_len` contains the correct size rather than 0.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu wudevelops@gmail.com --- kernel/bpf/syscall.c | 25 +++++++++++++------ .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++--- 2 files changed, 20 insertions(+), 11 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..90b6add4d0c9 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,7 +3565,7 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) }
static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { @@ -3574,18 +3574,20 @@ static int bpf_perf_link_fill_common(const struct perf_event *event, size_t len; int err;
- if (!ulen ^ !uname) + if (!(*ulen) ^ !uname) return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; + + len = strlen(buf); + *ulen = len + 1; if (!uname) return 0; if (buf) { - len = strlen(buf); - err = bpf_copy_to_user(uname, buf, ulen, len); + err = bpf_copy_to_user(uname, buf, *ulen, len); if (err) return err; } else { @@ -3609,7 +3611,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err; @@ -3617,7 +3619,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE; - + info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred())) @@ -3639,7 +3641,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err; @@ -3648,6 +3650,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0; @@ -3673,12 +3676,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen; + int err;
uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len; + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); + if (err) + return err; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie; - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); + return 0; }
static int bpf_perf_link_fill_perf_event(const struct perf_event *event, diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..59077f260404 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
+ ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len"); if (!info.perf_event.kprobe.func_name) { - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again; @@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT: + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len"); if (!info.perf_event.tracepoint.tp_name) { - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again; @@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+ ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len"); if (!info.perf_event.uprobe.file_name) { - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again;
On Mon, Sep 30, 2024 at 11:59:20PM +0000, tyrone-wu wrote:
Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name. The relevant selftests have also been updated to assert that `name_len` contains the correct size rather than 0.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu wudevelops@gmail.com
kernel/bpf/syscall.c | 25 +++++++++++++------ .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++--- 2 files changed, 20 insertions(+), 11 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..90b6add4d0c9 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,7 +3565,7 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) } static int bpf_perf_link_fill_common(const struct perf_event *event,
char __user *uname, u32 ulen,
char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed){ @@ -3574,18 +3574,20 @@ static int bpf_perf_link_fill_common(const struct perf_event *event, size_t len; int err;
- if (!ulen ^ !uname)
- if (!(*ulen) ^ !uname) return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err;
- len = strlen(buf);
- *ulen = len + 1;
I think before you overwrite *ulen with actual name lenth you should store its value and use it in bpf_copy_to_user, otherwise we could overwrite user space memory that we are not supposed to
jirka
if (!uname) return 0; if (buf) {
len = strlen(buf);err = bpf_copy_to_user(uname, buf, ulen, len);
err = bpf_copy_to_user(uname, buf, *ulen, len);@@ -3609,7 +3611,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len;
- err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
- err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err;
SNIP
Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name. The relevant selftests have also been updated to assert that `name_len` contains the correct size rather than 0.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu wudevelops@gmail.com --- V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ - Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 29 +++++++++++++------ .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++-- 2 files changed, 23 insertions(+), 12 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..26cc18693924 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) }
static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; u32 prog_id; - size_t len; + size_t len, name_len; int err;
- if (!ulen ^ !uname) + if (!(*ulen) ^ !uname) return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; + + name_len = *ulen; + len = strlen(buf); + *ulen = len + 1; if (!uname) return 0; + if (buf) { - len = strlen(buf); - err = bpf_copy_to_user(uname, buf, ulen, len); + err = bpf_copy_to_user(uname, buf, name_len, len); if (err) return err; } else { @@ -3609,7 +3613,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err; @@ -3617,7 +3621,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE; - + info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred())) @@ -3639,7 +3643,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err; @@ -3648,6 +3652,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0; @@ -3673,12 +3678,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen; + int err;
uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len; + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); + if (err) + return err; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie; - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); + return 0; }
static int bpf_perf_link_fill_perf_event(const struct perf_event *event, diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..59077f260404 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
+ ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len"); if (!info.perf_event.kprobe.func_name) { - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again; @@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT: + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len"); if (!info.perf_event.tracepoint.tp_name) { - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again; @@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+ ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len"); if (!info.perf_event.uprobe.file_name) { - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again;
On Wed, Oct 02, 2024 at 09:38:39PM +0000, tyrone-wu wrote:
Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name. The relevant selftests have also been updated to assert that `name_len` contains the correct size rather than 0.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu wudevelops@gmail.com
V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
- Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 29 +++++++++++++------ .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++-- 2 files changed, 23 insertions(+), 12 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..26cc18693924 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) } static int bpf_perf_link_fill_common(const struct perf_event *event,
char __user *uname, u32 ulen,
char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed){ const char *buf; u32 prog_id;
- size_t len;
- size_t len, name_len;
int err;
- if (!ulen ^ !uname)
- if (!(*ulen) ^ !uname) return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err;
- name_len = *ulen;
- len = strlen(buf);
- *ulen = len + 1; if (!uname) return 0;
- if (buf) {
len = strlen(buf);err = bpf_copy_to_user(uname, buf, ulen, len);
err = bpf_copy_to_user(uname, buf, name_len, len);
small nit.. up to you but I'd suggest bit different naming like below, otherwise looks good
Acked-by: Jiri Olsa jolsa@kernel.org
thanks, jirka
--- diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..b637e9dced5a 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,26 +3565,28 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) }
static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulenp, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; - u32 prog_id; + u32 prog_id, ulen; size_t len; int err;
- if (!ulen ^ !uname) + if (!(*ulenp) ^ !uname) return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; + ulen = *ulenp; + len = strlen(buf); + *ulenp = len + 1; if (!uname) return 0; if (buf) { - len = strlen(buf); err = bpf_copy_to_user(uname, buf, ulen, len); if (err) return err;
Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name. The relevant selftests have also been updated to assert that `name_len` contains the correct size rather than 0.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu wudevelops@gmail.com --- V2 -> V3: Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/ - Use clearer variable name for user set/inputted name len (name_len -> input_len) - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ - Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 29 +++++++++++++------ .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++-- 2 files changed, 23 insertions(+), 12 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..56c556fcf325 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) }
static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; - u32 prog_id; + u32 prog_id, input_len; size_t len; int err;
- if (!ulen ^ !uname) + if (!(*ulen) ^ !uname) return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; + + input_len = *ulen; + len = strlen(buf); + *ulen = len + 1; if (!uname) return 0; + if (buf) { - len = strlen(buf); - err = bpf_copy_to_user(uname, buf, ulen, len); + err = bpf_copy_to_user(uname, buf, input_len, len); if (err) return err; } else { @@ -3609,7 +3613,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err; @@ -3617,7 +3621,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE; - + info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred())) @@ -3639,7 +3643,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err; @@ -3648,6 +3652,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0; @@ -3673,12 +3678,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen; + int err;
uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len; + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); + if (err) + return err; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie; - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); + return 0; }
static int bpf_perf_link_fill_perf_event(const struct perf_event *event, diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..59077f260404 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
+ ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len"); if (!info.perf_event.kprobe.func_name) { - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again; @@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT: + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len"); if (!info.perf_event.tracepoint.tp_name) { - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again; @@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+ ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len"); if (!info.perf_event.uprobe.file_name) { - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again;
On Thu, Oct 03, 2024 at 08:23:00PM +0000, tyrone-wu wrote:
Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name. The relevant selftests have also been updated to assert that `name_len` contains the correct size rather than 0.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu wudevelops@gmail.com
V2 -> V3: Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/
- Use clearer variable name for user set/inputted name len (name_len -> input_len)
- Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
looks good, I checked with Daniel and it's better to separate kernel and selftest changes, so it's easier to get this applied in stable branches
could you split the change in 2 changes and repost? please keep my ack
thanks, jirka
V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
- Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 29 +++++++++++++------ .../selftests/bpf/prog_tests/fill_link_info.c | 6 ++-- 2 files changed, 23 insertions(+), 12 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..56c556fcf325 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) } static int bpf_perf_link_fill_common(const struct perf_event *event,
char __user *uname, u32 ulen,
char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed){ const char *buf;
- u32 prog_id;
- u32 prog_id, input_len; size_t len; int err;
- if (!ulen ^ !uname)
- if (!(*ulen) ^ !uname) return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err;
- input_len = *ulen;
- len = strlen(buf);
- *ulen = len + 1; if (!uname) return 0;
- if (buf) {
len = strlen(buf);err = bpf_copy_to_user(uname, buf, ulen, len);
err = bpf_copy_to_user(uname, buf, input_len, len);@@ -3609,7 +3613,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len;
- err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
- err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err;
@@ -3617,7 +3621,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE;
- info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred()))
@@ -3639,7 +3643,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len;
- err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
- err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err;
@@ -3648,6 +3652,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE;
- info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0;
@@ -3673,12 +3678,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen;
- int err;
uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len;
- err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL);
- if (err)
return err;- info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT;
- info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie;
- return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL);
- return 0;
} static int bpf_perf_link_fill_perf_event(const struct perf_event *event, diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..59077f260404 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len");
ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again;@@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT:
ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len");
ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again;@@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len");
ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again;-- 2.43.0
Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu wudevelops@gmail.com Acked-by: Jiri Olsa jolsa@kernel.org --- V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ - Split patch into separate kernel and selftest change
V2 -> V3: Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/ - Use clearer variable name for user set/inputted name len (name_len -> input_len) - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ - Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 29 ++++++++++++++++++++--------- 1 file changed, 20 insertions(+), 9 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..56c556fcf325 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) }
static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; - u32 prog_id; + u32 prog_id, input_len; size_t len; int err;
- if (!ulen ^ !uname) + if (!(*ulen) ^ !uname) return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; + + input_len = *ulen; + len = strlen(buf); + *ulen = len + 1; if (!uname) return 0; + if (buf) { - len = strlen(buf); - err = bpf_copy_to_user(uname, buf, ulen, len); + err = bpf_copy_to_user(uname, buf, input_len, len); if (err) return err; } else { @@ -3609,7 +3613,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err; @@ -3617,7 +3621,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE; - + info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred())) @@ -3639,7 +3643,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err; @@ -3648,6 +3652,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0; @@ -3673,12 +3678,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen; + int err;
uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len; + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); + if (err) + return err; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie; - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); + return 0; }
static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
Fix `name_len` field assertions in `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint to validate correct name size instead of 0.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info") Signed-off-by: tyrone-wu wudevelops@gmail.com Acked-by: Jiri Olsa jolsa@kernel.org --- V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ - Split patch into separate kernel and selftest change
tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..59077f260404 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
+ ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len"); if (!info.perf_event.kprobe.func_name) { - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again; @@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT: + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len"); if (!info.perf_event.tracepoint.tp_name) { - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again; @@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+ ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len"); if (!info.perf_event.uprobe.file_name) { - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again;
On Fri, Oct 4, 2024 at 11:40 PM tyrone-wu wudevelops@gmail.com wrote:
Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu wudevelops@gmail.com Acked-by: Jiri Olsa jolsa@kernel.org
V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
- Split patch into separate kernel and selftest change
V2 -> V3: Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/
- Use clearer variable name for user set/inputted name len (name_len -> input_len)
- Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
- Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 29 ++++++++++++++++++++--------- 1 file changed, 20 insertions(+), 9 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..56c556fcf325 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) }
static int bpf_perf_link_fill_common(const struct perf_event *event,
char __user *uname, u32 ulen,
char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed){ const char *buf;
u32 prog_id;
u32 prog_id, input_len; size_t len; int err;
if (!ulen ^ !uname)
if (!(*ulen) ^ !uname) return -EINVAL; err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err;input_len = *ulen;len = strlen(buf);
The buf might be NULL, so we should check it.
*ulen = len + 1; if (!uname) return 0;if (buf) {
len = strlen(buf);err = bpf_copy_to_user(uname, buf, ulen, len);
err = bpf_copy_to_user(uname, buf, input_len, len); if (err) return err; } else {@@ -3609,7 +3613,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len;
err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err;@@ -3617,7 +3621,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE;
info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred()))@@ -3639,7 +3643,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len;
err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err;@@ -3648,6 +3652,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE;
info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0;@@ -3673,12 +3678,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen;
int err; uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len;err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL);if (err)return err;info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT;info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie;
return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL);
return 0;}
static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
2.43.0
-- Regards
Yafang
Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu wudevelops@gmail.com Acked-by: Jiri Olsa jolsa@kernel.org --- V4 -> V5: Link: https://lore.kernel.org/bpf/CALOAHbC5xm7Cbfhau3z5X2PqUhiHECNWAPtJCWiOVqTKmdZ... - Check that buf is not NULL before retrieving/using its length
V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ - Split patch into separate kernel and selftest change
V2 -> V3: Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/ - Use clearer variable name for user set/inputted name len (name_len -> input_len) - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ - Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 38 ++++++++++++++++++++++++-------------- 1 file changed, 24 insertions(+), 14 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..3df192a6bdcc 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,32 +3565,35 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) }
static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; - u32 prog_id; + u32 prog_id, input_len; size_t len; int err;
- if (!ulen ^ !uname) + if (!(*ulen) ^ !uname) return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; - if (!uname) - return 0; + if (buf) { + input_len = *ulen; len = strlen(buf); - err = bpf_copy_to_user(uname, buf, ulen, len); - if (err) - return err; - } else { - char zero = '\0'; + *ulen = len + 1;
+ if (uname) { + err = bpf_copy_to_user(uname, buf, input_len, len); + if (err) + return err; + } + } else if (uname) { + char zero = '\0'; if (put_user(zero, uname)) return -EFAULT; } @@ -3609,7 +3612,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err; @@ -3617,7 +3620,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE; - + info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred())) @@ -3639,7 +3642,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err; @@ -3648,6 +3651,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0; @@ -3673,12 +3677,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen; + int err;
uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len; + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); + if (err) + return err; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie; - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); + return 0; }
static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
Fix `name_len` field assertions in `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint to validate correct name size instead of 0.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info") Signed-off-by: tyrone-wu wudevelops@gmail.com Acked-by: Jiri Olsa jolsa@kernel.org --- V4 -> V5: no change
V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ - Split patch into separate kernel and selftest change
tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..59077f260404 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
+ ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len"); if (!info.perf_event.kprobe.func_name) { - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again; @@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT: + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len"); if (!info.perf_event.tracepoint.tp_name) { - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again; @@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+ ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len"); if (!info.perf_event.uprobe.file_name) { - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again;
On Mon, Oct 7, 2024 at 3:51 AM tyrone-wu wudevelops@gmail.com wrote:
Fix `name_len` field assertions in `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint to validate correct name size instead of 0.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info") Signed-off-by: tyrone-wu wudevelops@gmail.com Acked-by: Jiri Olsa jolsa@kernel.org
Acked-by: Yafang Shao laoar.shao@gmail.com
V4 -> V5: no change
V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
- Split patch into separate kernel and selftest change
tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..59077f260404 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, "name_len"); if (!info.perf_event.kprobe.func_name) {
ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again;@@ -79,8 +79,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT:
ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, "name_len"); if (!info.perf_event.tracepoint.tp_name) {
ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again;@@ -96,8 +96,8 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, "name_len"); if (!info.perf_event.uprobe.file_name) {
ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again;-- 2.43.0
On Mon, Oct 7, 2024 at 3:51 AM tyrone-wu wudevelops@gmail.com wrote:
Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu wudevelops@gmail.com Acked-by: Jiri Olsa jolsa@kernel.org
LGTM Acked-by: Yafang Shao laoar.shao@gmail.com
V4 -> V5: Link: https://lore.kernel.org/bpf/CALOAHbC5xm7Cbfhau3z5X2PqUhiHECNWAPtJCWiOVqTKmdZ...
- Check that buf is not NULL before retrieving/using its length
V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
- Split patch into separate kernel and selftest change
V2 -> V3: Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/
- Use clearer variable name for user set/inputted name len (name_len -> input_len)
- Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
- Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 38 ++++++++++++++++++++++++-------------- 1 file changed, 24 insertions(+), 14 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..3df192a6bdcc 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,32 +3565,35 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) }
static int bpf_perf_link_fill_common(const struct perf_event *event,
char __user *uname, u32 ulen,
char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed){ const char *buf;
u32 prog_id;
u32 prog_id, input_len; size_t len; int err;
if (!ulen ^ !uname)
if (!(*ulen) ^ !uname) return -EINVAL; err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err;
if (!uname)return 0;
if (buf) {input_len = *ulen; len = strlen(buf);
err = bpf_copy_to_user(uname, buf, ulen, len);if (err)return err;} else {char zero = '\0';
*ulen = len + 1;if (uname) {err = bpf_copy_to_user(uname, buf, input_len, len);if (err)return err;}} else if (uname) {char zero = '\0'; if (put_user(zero, uname)) return -EFAULT; }@@ -3609,7 +3612,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len;
err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err;@@ -3617,7 +3620,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE;
info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred()))@@ -3639,7 +3642,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len;
err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err;@@ -3648,6 +3651,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE;
info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0;@@ -3673,12 +3677,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen;
int err; uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len;err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL);if (err)return err;info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT;info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie;
return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL);
return 0;}
static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
2.43.0
On Sun, Oct 06, 2024 at 07:51:30PM +0000, tyrone-wu wrote:
Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: tyrone-wu wudevelops@gmail.com Acked-by: Jiri Olsa jolsa@kernel.org
V4 -> V5: Link: https://lore.kernel.org/bpf/CALOAHbC5xm7Cbfhau3z5X2PqUhiHECNWAPtJCWiOVqTKmdZ...
- Check that buf is not NULL before retrieving/using its length
V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
- Split patch into separate kernel and selftest change
V2 -> V3: Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/
- Use clearer variable name for user set/inputted name len (name_len -> input_len)
- Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
- Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 38 ++++++++++++++++++++++++-------------- 1 file changed, 24 insertions(+), 14 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..3df192a6bdcc 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,32 +3565,35 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) } static int bpf_perf_link_fill_common(const struct perf_event *event,
char __user *uname, u32 ulen,
char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed){ const char *buf;
- u32 prog_id;
- u32 prog_id, input_len; size_t len; int err;
- if (!ulen ^ !uname)
- if (!(*ulen) ^ !uname) return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err;
- if (!uname)
return 0;
- if (buf) {
input_len = *ulen;
err = bpf_copy_to_user(uname, buf, ulen, len);if (err)return err;- } else {
char zero = '\0';
*ulen = len + 1;
if (uname) {err = bpf_copy_to_user(uname, buf, input_len, len);if (err)return err;}- } else if (uname) {
char zero = '\0';
hm, why not just simple check buf for and keep the rest? seems less complicated..
jirka
--- diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..e393b94b90ec 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,27 +3565,31 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) }
static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; - u32 prog_id; + u32 prog_id, input_len; size_t len; int err;
- if (!ulen ^ !uname) + if (!(*ulen) ^ !uname) return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; + if (buf) { + input_len = *ulen; + len = strlen(buf); + *ulen = len + 1; + } if (!uname) return 0; if (buf) { - len = strlen(buf); - err = bpf_copy_to_user(uname, buf, ulen, len); + err = bpf_copy_to_user(uname, buf, input_len, len); if (err) return err; } else {
From: tyrone-wu wudevelops@gmail.com
Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: Tyrone Wu wudevelops@gmail.com Acked-by: Jiri Olsa jolsa@kernel.org Acked-by: Yafang Shao laoar.shao@gmail.com --- V5 -> V6: Link: https://lore.kernel.org/bpf/ZwOWs_XrBtlTGE24@krava/ - Use simpler buf check while keeping V4 - Fix netdev/checkpatch warning for 80 cols exceeded - Fix Signed-off-by to use real name instead of git username
V4 -> V5: Link: https://lore.kernel.org/bpf/CALOAHbC5xm7Cbfhau3z5X2PqUhiHECNWAPtJCWiOVqTKmdZ... - Check that buf is not NULL before retrieving/using its length
V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ - Split patch into separate kernel and selftest change
V2 -> V3: Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/ - Use clearer variable name for user set/inputted name len (name_len -> input_len) - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/ - Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..b5a7e428ac16 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,27 +3565,33 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) }
static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulen, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; - u32 prog_id; + u32 prog_id, input_len; size_t len; int err;
- if (!ulen ^ !uname) + if (!(*ulen) ^ !uname) return -EINVAL;
err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err; + + if (buf) { + input_len = *ulen; + len = strlen(buf); + *ulen = len + 1; + } if (!uname) return 0; + if (buf) { - len = strlen(buf); - err = bpf_copy_to_user(uname, buf, ulen, len); + err = bpf_copy_to_user(uname, buf, input_len, len); if (err) return err; } else { @@ -3609,7 +3615,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err; @@ -3617,7 +3623,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE; - + info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred())) @@ -3639,7 +3645,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err; @@ -3648,6 +3654,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0; @@ -3673,12 +3680,19 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen; + int err;
uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len; + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, + NULL); + if (err) + return err; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie; - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); + return 0; }
static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
From: tyrone-wu wudevelops@gmail.com
Fix `name_len` field assertions in `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint to validate correct name size instead of 0.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info") Signed-off-by: Tyrone Wu wudevelops@gmail.com Acked-by: Jiri Olsa jolsa@kernel.org Acked-by: Yafang Shao laoar.shao@gmail.com --- V5 -> V6: - Fix netdev/checkpatch warning for 80 cols exceeded - Fix Signed-off-by to use real name instead of git username
V4 -> V5: no change
V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/ - Split patch into separate kernel and selftest change
tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..745c5ada4c4b 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
+ ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, + "name_len"); if (!info.perf_event.kprobe.func_name) { - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again; @@ -79,8 +80,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT: + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, + "name_len"); if (!info.perf_event.tracepoint.tp_name) { - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again; @@ -96,8 +98,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+ ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, + "name_len"); if (!info.perf_event.uprobe.file_name) { - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again;
On Mon, Oct 7, 2024 at 11:29 AM Tyrone Wu wudevelops@gmail.com wrote:
From: tyrone-wu wudevelops@gmail.com
Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name.
Link: https://lore.kernel.org/bpf/CABVU1kXwQXhqQGe0RTrr7eegtM6SVW_KayZBy16-yb0Snzt... Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: Tyrone Wu wudevelops@gmail.com Acked-by: Jiri Olsa jolsa@kernel.org Acked-by: Yafang Shao laoar.shao@gmail.com
V5 -> V6: Link: https://lore.kernel.org/bpf/ZwOWs_XrBtlTGE24@krava/
- Use simpler buf check while keeping V4
- Fix netdev/checkpatch warning for 80 cols exceeded
- Fix Signed-off-by to use real name instead of git username
V4 -> V5: Link: https://lore.kernel.org/bpf/CALOAHbC5xm7Cbfhau3z5X2PqUhiHECNWAPtJCWiOVqTKmdZ...
- Check that buf is not NULL before retrieving/using its length
V3 -> V4: Link: https://lore.kernel.org/bpf/Zv_PP6Gs5cq3W2Ey@krava/
- Split patch into separate kernel and selftest change
V2 -> V3: Link: https://lore.kernel.org/bpf/Zv7sISV0yEyGlEM3@krava/
- Use clearer variable name for user set/inputted name len (name_len -> input_len)
- Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
V1 -> V2: Link: https://lore.kernel.org/bpf/Zv0wl-S13WJnIkb_@krava/
Please drop all the Link: tags, our scripts will accumulate all of them in the final commit and it becomes very confusing. Our script will add the final Link: for your latest applied version anyways.
Also, git still shows:
Author: tyrone-wu wudevelops@gmail.com
So please try to fix that.
But generally, looks good and I almost applied, but see one small issue below, which I think needs fixing.
pw-bot: cr
- Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 32 +++++++++++++++++++++++--------- 1 file changed, 23 insertions(+), 9 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..b5a7e428ac16 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,27 +3565,33 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) }
static int bpf_perf_link_fill_common(const struct perf_event *event,
char __user *uname, u32 ulen,
char __user *uname, u32 *ulen,
nit: I'd do what Jiri suggested, use `u32 *ulenp` here
u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed){ const char *buf;
u32 prog_id;
u32 prog_id, input_len;
and then just `u32 ulen;` here.
size_t len; int err;
start with just
ulen = *ulenp;
if (!ulen ^ !uname)
if (!(*ulen) ^ !uname)
and remove all the `*ulen` uses except the final assignment
return -EINVAL; err = bpf_get_perf_event_info(event, &prog_id, fd_type, &buf, probe_offset, probe_addr, missed); if (err) return err;
if (buf) {input_len = *ulen;len = strlen(buf);*ulen = len + 1;}
don't we need
} else { *ulen = 1; }
for cases when we don't have buf returned from bpf_get_perf_event_info()? Though I don't think it can happen currently, existing code is clearly ready to handle that case, so let's keep it consistent.
if (!uname) return 0;
if (buf) {
len = strlen(buf);err = bpf_copy_to_user(uname, buf, ulen, len);
err = bpf_copy_to_user(uname, buf, input_len, len); if (err) return err; } else {@@ -3609,7 +3615,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len;
err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err;@@ -3617,7 +3623,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE;
info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred()))@@ -3639,7 +3645,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len;
err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr,
err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err;@@ -3648,6 +3654,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE;
info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0;@@ -3673,12 +3680,19 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen;
int err; uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len;err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL,NULL);
nit: keep it on a single line
if (err)return err;info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT;info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie;
return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL);
return 0;}
static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
2.43.0
Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name.
Fixes: 1b715e1b0ec5 ("bpf: Support ->fill_link_info for perf_event") Signed-off-by: Tyrone Wu wudevelops@gmail.com Acked-by: Jiri Olsa jolsa@kernel.org Acked-by: Yafang Shao laoar.shao@gmail.com --- V6 -> V7: - Use *ulenp suggestion from Jiri for user name_len - Set user name_len to 1 when buf returned from bpf_get_perf_event_info() is NULL
V5 -> V6: - Use simpler buf check while keeping V4 - Fix netdev/checkpatch warning for 80 cols exceeded - Fix Signed-off-by to use real name instead of git username
V4 -> V5: - Check that buf is not NULL before retrieving/using its length
V3 -> V4: - Split patch into separate kernel and selftest change
V2 -> V3: - Use clearer variable name for user set/inputted name len (name_len -> input_len) - Change (name_len -> input_len) type from size_t to u32 since it's only received and used as u32
V1 -> V2: - Use user set *ulen in bpf_copy_to_user before overwriting *ulen
kernel/bpf/syscall.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-)
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index a8f1808a1ca5..8cfa7183d2ef 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -3565,15 +3565,16 @@ static void bpf_perf_link_dealloc(struct bpf_link *link) }
static int bpf_perf_link_fill_common(const struct perf_event *event, - char __user *uname, u32 ulen, + char __user *uname, u32 *ulenp, u64 *probe_offset, u64 *probe_addr, u32 *fd_type, unsigned long *missed) { const char *buf; - u32 prog_id; + u32 prog_id, ulen; size_t len; int err;
+ ulen = *ulenp; if (!ulen ^ !uname) return -EINVAL;
@@ -3581,10 +3582,17 @@ static int bpf_perf_link_fill_common(const struct perf_event *event, probe_offset, probe_addr, missed); if (err) return err; + + if (buf) { + len = strlen(buf); + *ulenp = len + 1; + } else { + *ulenp = 1; + } if (!uname) return 0; + if (buf) { - len = strlen(buf); err = bpf_copy_to_user(uname, buf, ulen, len); if (err) return err; @@ -3609,7 +3617,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.kprobe.func_name); ulen = info->perf_event.kprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, &missed); if (err) return err; @@ -3617,7 +3625,7 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_KRETPROBE; else info->perf_event.type = BPF_PERF_EVENT_KPROBE; - + info->perf_event.kprobe.name_len = ulen; info->perf_event.kprobe.offset = offset; info->perf_event.kprobe.missed = missed; if (!kallsyms_show_value(current_cred())) @@ -3639,7 +3647,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name); ulen = info->perf_event.uprobe.name_len; - err = bpf_perf_link_fill_common(event, uname, ulen, &offset, &addr, + err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr, &type, NULL); if (err) return err; @@ -3648,6 +3656,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event, info->perf_event.type = BPF_PERF_EVENT_URETPROBE; else info->perf_event.type = BPF_PERF_EVENT_UPROBE; + info->perf_event.uprobe.name_len = ulen; info->perf_event.uprobe.offset = offset; info->perf_event.uprobe.cookie = event->bpf_cookie; return 0; @@ -3673,12 +3682,18 @@ static int bpf_perf_link_fill_tracepoint(const struct perf_event *event, { char __user *uname; u32 ulen; + int err;
uname = u64_to_user_ptr(info->perf_event.tracepoint.tp_name); ulen = info->perf_event.tracepoint.name_len; + err = bpf_perf_link_fill_common(event, uname, &ulen, NULL, NULL, NULL, NULL); + if (err) + return err; + info->perf_event.type = BPF_PERF_EVENT_TRACEPOINT; + info->perf_event.tracepoint.name_len = ulen; info->perf_event.tracepoint.cookie = event->bpf_cookie; - return bpf_perf_link_fill_common(event, uname, ulen, NULL, NULL, NULL, NULL); + return 0; }
static int bpf_perf_link_fill_perf_event(const struct perf_event *event,
Fix `name_len` field assertions in `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint to validate correct name size instead of 0.
Fixes: 23cf7aa539dc ("selftests/bpf: Add selftest for fill_link_info") Signed-off-by: Tyrone Wu wudevelops@gmail.com Acked-by: Jiri Olsa jolsa@kernel.org Acked-by: Yafang Shao laoar.shao@gmail.com --- V6 -> V7: no change
V5 -> V6: - Fix netdev/checkpatch warning for 80 cols exceeded - Fix Signed-off-by to use real name instead of git username
V4 -> V5: no change
V3 -> V4: - Split patch into separate kernel and selftest change
tools/testing/selftests/bpf/prog_tests/fill_link_info.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c index f3932941bbaa..745c5ada4c4b 100644 --- a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c @@ -67,8 +67,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
ASSERT_EQ(info.perf_event.kprobe.cookie, PERF_EVENT_COOKIE, "kprobe_cookie");
+ ASSERT_EQ(info.perf_event.kprobe.name_len, strlen(KPROBE_FUNC) + 1, + "name_len"); if (!info.perf_event.kprobe.func_name) { - ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len"); info.perf_event.kprobe.func_name = ptr_to_u64(&buf); info.perf_event.kprobe.name_len = sizeof(buf); goto again; @@ -79,8 +80,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add ASSERT_EQ(err, 0, "cmp_kprobe_func_name"); break; case BPF_PERF_EVENT_TRACEPOINT: + ASSERT_EQ(info.perf_event.tracepoint.name_len, strlen(TP_NAME) + 1, + "name_len"); if (!info.perf_event.tracepoint.tp_name) { - ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len"); info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf); info.perf_event.tracepoint.name_len = sizeof(buf); goto again; @@ -96,8 +98,9 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add case BPF_PERF_EVENT_URETPROBE: ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
+ ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1, + "name_len"); if (!info.perf_event.uprobe.file_name) { - ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len"); info.perf_event.uprobe.file_name = ptr_to_u64(&buf); info.perf_event.uprobe.name_len = sizeof(buf); goto again;
Hello:
This series was applied to bpf/bpf.git (master) by Alexei Starovoitov ast@kernel.org:
On Tue, 8 Oct 2024 16:43:11 +0000 you wrote:
Previously when retrieving `bpf_link_info.perf_event` for kprobe/uprobe/tracepoint, the `name_len` field was not populated by the kernel, leaving it to reflect the value initially set by the user. This behavior was inconsistent with how other input/output string buffer fields function (e.g. `raw_tracepoint.tp_name_len`).
This patch fills `name_len` with the actual size of the string name.
[...]
Here is the summary with links: - [bpf,v7,1/2] bpf: fix unpopulated name_len field in perf_event link info https://git.kernel.org/bpf/bpf/c/4deecdd29cf2 - [bpf,v7,2/2] selftests/bpf: fix perf_event link info name_len assertion https://git.kernel.org/bpf/bpf/c/4538a38f654a
You are awesome, thank you!
linux-kselftest-mirror@lists.linaro.org
-
Andrii Nakryiko -
Jiri Olsa -
patchwork-bot+netdevbpf＠kernel.org -
Tyrone Wu -
tyrone-wu
-
Yafang Shao