6.6-stable review patch. If anyone has any objections, please let me know.
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From: Jiri Olsa jolsa@kernel.org
[ Upstream commit 4930b7f53a298533bc31d7540b6ea8b79a000331 ]
We will need to return ref_ctr_offsets values through link_info interface in following change, so we need to keep them around.
Storing ref_ctr_offsets values directly into bpf_uprobe array.
Signed-off-by: Jiri Olsa jolsa@kernel.org Signed-off-by: Andrii Nakryiko andrii@kernel.org Acked-by: Andrii Nakryiko andrii@kernel.org Acked-by: Song Liu song@kernel.org Link: https://lore.kernel.org/bpf/20231125193130.834322-3-jolsa@kernel.org Stable-dep-of: 2884dc7d08d9 ("bpf: Fix a potential use-after-free in bpf_link_free()") Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/trace/bpf_trace.c | 14 +++----------- 1 file changed, 3 insertions(+), 11 deletions(-)
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 1e79084a9d9d2..8edbafe0d4cdf 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -3030,6 +3030,7 @@ struct bpf_uprobe_multi_link; struct bpf_uprobe { struct bpf_uprobe_multi_link *link; loff_t offset; + unsigned long ref_ctr_offset; u64 cookie; struct uprobe_consumer consumer; }; @@ -3169,7 +3170,6 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr { struct bpf_uprobe_multi_link *link = NULL; unsigned long __user *uref_ctr_offsets; - unsigned long *ref_ctr_offsets = NULL; struct bpf_link_primer link_primer; struct bpf_uprobe *uprobes = NULL; struct task_struct *task = NULL; @@ -3244,18 +3244,12 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr if (!uprobes || !link) goto error_free;
- if (uref_ctr_offsets) { - ref_ctr_offsets = kvcalloc(cnt, sizeof(*ref_ctr_offsets), GFP_KERNEL); - if (!ref_ctr_offsets) - goto error_free; - } - for (i = 0; i < cnt; i++) { if (ucookies && __get_user(uprobes[i].cookie, ucookies + i)) { err = -EFAULT; goto error_free; } - if (uref_ctr_offsets && __get_user(ref_ctr_offsets[i], uref_ctr_offsets + i)) { + if (uref_ctr_offsets && __get_user(uprobes[i].ref_ctr_offset, uref_ctr_offsets + i)) { err = -EFAULT; goto error_free; } @@ -3286,7 +3280,7 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr for (i = 0; i < cnt; i++) { err = uprobe_register_refctr(d_real_inode(link->path.dentry), uprobes[i].offset, - ref_ctr_offsets ? ref_ctr_offsets[i] : 0, + uprobes[i].ref_ctr_offset, &uprobes[i].consumer); if (err) { bpf_uprobe_unregister(&path, uprobes, i); @@ -3298,11 +3292,9 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr if (err) goto error_free;
- kvfree(ref_ctr_offsets); return bpf_link_settle(&link_primer);
error_free: - kvfree(ref_ctr_offsets); kvfree(uprobes); kfree(link); if (task)