diff options
| author | Jiri Olsa <jolsa@kernel.org> | 2026-08-03 23:01:46 +0200 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2026-08-05 11:32:29 -0700 |
| commit | f5d242825ca417bb6afe35fde6e8880f97ca43fb (patch) | |
| tree | 8a764780201fae4e07d27fe8f78d78b95e4a163f /kernel | |
| parent | 58cfc2201d964163fe9c4a703136eb64db799f08 (diff) | |
bpf: Clear buf on error in __bpf_get_task_stack
Both bpf_get_task_stack and bpf_get_task_stack_sleepable helpers that
use __bpf_get_task_stack have buf defined as ARG_PTR_TO_UNINIT_MEM
argument and we should initialize the buf on every return path.
Adding missing buf memset for __bpf_get_task_stack fail paths. This
provides deterministic buffer contents, which is useful when the buffer
is used directly as a map key.
Fixes: 06ab134ce8ec ("bpf: Refcount task stack in bpf_get_task_stack")
Fixes: b992f01e6615 ("bpf: Guard against accessing NULL pt_regs in bpf_get_task_stack()")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260803210149.296496-10-jolsa@kernel.org
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/stackmap.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c index 976c4e4c1af6..7f728d319a65 100644 --- a/kernel/bpf/stackmap.c +++ b/kernel/bpf/stackmap.c @@ -884,14 +884,17 @@ static long __bpf_get_task_stack(struct task_struct *task, void *buf, u32 size, struct pt_regs *regs; long res = -EINVAL; - if (!try_get_task_stack(task)) + if (!try_get_task_stack(task)) { + memset(buf, 0, size); return -EFAULT; + } regs = task_pt_regs(task); if (regs) res = __bpf_get_stack(regs, task, buf, size, flags, may_fault); + else + memset(buf, 0, size); put_task_stack(task); - return res; } |