diff options
| author | Masami Hiramatsu (Google) <mhiramat@kernel.org> | 2026-07-29 09:28:07 +0900 |
|---|---|---|
| committer | Steven Rostedt <rostedt@goodmis.org> | 2026-07-29 14:32:11 -0400 |
| commit | c22c7b735f9810ad276014f788f9aa5c879ec238 (patch) | |
| tree | f4e298f2d08d4b040d114d784d5e3b1d7db596d8 /kernel/trace | |
| parent | ac8719969e6c3c54e939834df812bc41f25453cf (diff) | |
tracing/filters: Fix false positive match in regex_match_full()
regex_match_full() calls strncmp(str, r->pattern, len) where len is the
target field buffer size. When len is smaller than r->len (the filter
pattern length), strncmp() checks only len bytes of r->pattern against
str. If those len bytes match, strncmp() returns 0, resulting in a
false-positive match where a shorter string in a fixed-size field
matches a longer filter pattern.
For example, a 4-byte static string field containing "abcd" matched the
filter pattern "abcdefgh" because strncmp("abcd", "abcdefgh", 4)
returned 0. In this case, @len does NOT include '\0' because it is
fixed-size array.
Fix this by returning 0 (no match) early when len < r->len.
Fixes: 1889d20922d1 ("tracing/filters: Provide basic regex support")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/178528488779.124250.5571741156199253769.stgit@devnote2
Assisted-by: Antigravity:gemini-3.5-flash
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/trace_events_filter.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c index 6385cd662d8d..2b46ca536045 100644 --- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -1027,6 +1027,9 @@ static int regex_match_full(char *str, struct regex *r, int len) if (!len) return strcmp(str, r->pattern) == 0; + if (len < r->len) + return 0; + return strncmp(str, r->pattern, len) == 0; } |