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| author | Jiri Olsa <jolsa@kernel.org> | 2026-06-11 13:42:24 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-06-14 17:24:25 -0700 |
| commit | 4d87a251d45b4a95eb4c0abcfab809c9f231258a (patch) | |
| tree | 28b4b3383f3e1e42fedc8af984f598b6bd8d67fd /kernel | |
| parent | 16deef8de06ed69aa79d037a168a70407a84a5ca (diff) | |
| download | lwn-4d87a251d45b4a95eb4c0abcfab809c9f231258a.tar.gz lwn-4d87a251d45b4a95eb4c0abcfab809c9f231258a.zip | |
bpf: Guard __get_user acesss with access_ok for uprobe_multi data
As reported by sashiko [1] we need to use access_ok to check the user
space data bounds before we use __get-user to get it.
[1] https://lore.kernel.org/bpf/20260610145235.CB1441F00893@smtp.kernel.org/
Fixes: 0b779b61f651 ("bpf: Add cookies support for uprobe_multi link")
Fixes: 89ae89f53d20 ("bpf: Add multi uprobe link")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260611114230.950379-2-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/bpf_trace.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 90432f0fc2a8..b5a12af2d3f8 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -3224,6 +3224,7 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr unsigned long __user *uoffsets; u64 __user *ucookies; void __user *upath; + unsigned long size; u32 flags, cnt, i; struct path path; char *name; @@ -3261,6 +3262,16 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr uref_ctr_offsets = u64_to_user_ptr(attr->link_create.uprobe_multi.ref_ctr_offsets); ucookies = u64_to_user_ptr(attr->link_create.uprobe_multi.cookies); + /* + * All uoffsets/uref_ctr_offsets/ucookies arrays have the same value + * size, we need to check their address range is safe for __get_user + * calls. + */ + size = sizeof(*uoffsets) * cnt; + if (!access_ok(uoffsets, size) || !access_ok(uref_ctr_offsets, size) || + !access_ok(ucookies, size)) + return -EFAULT; + name = strndup_user(upath, PATH_MAX); if (IS_ERR(name)) { err = PTR_ERR(name); |