It seems that there is no reason not to support 32-bit architectures; doing so requires a bit of rework with respect to cookies handling, however, as the current code implicitly assumes that sizeof(long) == sizeof(u64).

Signed-off-by: Eugene Syromiatnikov esyr@redhat.com --- kernel/trace/bpf_trace.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index e90c4ce7..d228440 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -2405,16 +2405,12 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr struct bpf_link_primer link_primer; void __user *ucookies; unsigned long *addrs; - u32 flags, cnt, size; + u32 flags, cnt, size, cookies_size; void __user *uaddrs; u64 *cookies = NULL; void __user *usyms; int err;

- /* no support for 32bit archs yet */ - if (sizeof(u64) != sizeof(void *)) - return -EOPNOTSUPP; - if (prog->expected_attach_type != BPF_TRACE_KPROBE_MULTI) return -EINVAL;

@@ -2424,6 +2420,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr

uaddrs = u64_to_user_ptr(attr->link_create.kprobe_multi.addrs); usyms = u64_to_user_ptr(attr->link_create.kprobe_multi.syms); + ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies); if (!!uaddrs == !!usyms) return -EINVAL;

@@ -2431,8 +2428,11 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr if (!cnt) return -EINVAL;

- if (check_mul_overflow(cnt, (u32)sizeof(*addrs), &size)) + if (check_mul_overflow(cnt, (u32)sizeof(*addrs), &size) || + (ucookies && + check_mul_overflow(cnt, (u32)sizeof(*cookies), &cookies_size))) { return -EOVERFLOW; + } size = cnt * sizeof(*addrs); addrs = kvmalloc(size, GFP_KERNEL); if (!addrs) @@ -2449,14 +2449,14 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr goto error; }

- ucookies = u64_to_user_ptr(attr->link_create.kprobe_multi.cookies); if (ucookies) { - cookies = kvmalloc(size, GFP_KERNEL); + cookies_size = cnt * sizeof(*cookies); + cookies = kvmalloc(cookies_size, GFP_KERNEL); if (!cookies) { err = -ENOMEM; goto error; } - if (copy_from_user(cookies, ucookies, size)) { + if (copy_from_user(cookies, ucookies, cookies_size)) { err = -EFAULT; goto error; }