diff options
| author | Raushan Patel <raushan.jhon@gmail.com> | 2026-07-24 11:14:35 +0530 |
|---|---|---|
| committer | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2026-07-28 23:58:31 +0900 |
| commit | 00a8ce2a2a9fa17674e1feec4d9105c1a5d6a419 (patch) | |
| tree | 05dddaab413d01da2662b9cb416166cfe8efb202 | |
| parent | f5098b6bae761e346ebcd9da7f95622c04733cff (diff) | |
tracing/probes: Reject $arg0 in meta argument expansion
traceprobe_expand_meta_args() parses $argN with simple_strtoul() and
calls sprint_nth_btf_arg(n - 1, ...). For $arg0, n is 0 so the index is
-1. Because ctx->nr_params is signed, the "idx >= nr_params" guard in
sprint_nth_btf_arg() does not catch the negative index, and
ctx->params[-1].name_off is read out of bounds.
The normal per-argument path (parse_probe_vars()) already rejects
$arg0 via its argument-number check, but meta-argument expansion runs
before per-argument parsing and substitutes the value first, bypassing
that check.
Reject $arg0 explicitly during expansion.
Link: https://lore.kernel.org/all/20260724054435.146279-1-raushan.jhon@gmail.com/
Fixes: 18b1e870a496 ("tracing/probes: Add $arg* meta argument for all function args")
Cc: stable@vger.kernel.org
Signed-off-by: Raushan Patel <raushan.jhon@gmail.com>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
| -rw-r--r-- | kernel/trace/trace_probe.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 506e6037e163..c8fd9b946f44 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -1901,7 +1901,11 @@ const char **traceprobe_expand_meta_args(int argc, const char *argv[], trace_probe_log_err(0, BAD_VAR); return ERR_PTR(-ENOENT); } - /* Note: $argN starts from $arg1 */ + /* Note: $argN starts from $arg1, so $arg0 is invalid. */ + if (n == 0) { + trace_probe_log_err(0, BAD_ARG_NUM); + return ERR_PTR(-EINVAL); + } ret = sprint_nth_btf_arg(n - 1, type, buf + used, bufsize - used, ctx); if (ret < 0) |