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tracing: Prevent out-of-bounds read in glob matching

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String event fields are not necessarily NUL-terminated, so the filter
predicate functions (filter_pred_string(), filter_pred_strloc() and
filter_pred_strrelloc()) pass the field length to the regex match
callbacks, and the length-aware matchers honour it.

regex_match_glob() was the exception: it ignored the length and called
glob_match(), which scans the string until it hits a NUL byte. Some
string fields are not NUL-terminated. One example is the dynamic char
array of the xfs_* namespace tracepoints, which is copied without a
trailing NUL. For such a field, glob matching reads past the end of
the event field, causing a KASAN slab-out-of-bounds read in
glob_match(), reached via regex_match_glob() and filter_match_preds()
from the xfs_lookup tracepoint.

Add a length-bounded glob_match_len() and use it from regex_match_glob()
so glob matching always stops at the field boundary. The matching loop
is factored into a shared helper so glob_match() keeps its behaviour.

Fixes: 60f1d5e3ba ("ftrace: Support full glob matching")
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/da1aaf125fc3b63320b0c540fd6afa7c3d5b4f1a.1782836943.git.hhhuang@smu.edu.sg
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Zhengchuan Liang <zcliangcn@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Assisted-by: Codex:GPT-5.4
Signed-off-by: Huihui Huang <hhhuang@smu.edu.sg>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Huihui Huang
2026-07-01 18:28:46 +08:00
committed by Steven Rostedt
parent 535fcf4b8a
commit 0a6070839b
3 changed files with 32 additions and 6 deletions
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6
kernel/trace/trace_events_filter.c
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@@ -1056,11 +1056,9 @@ static int regex_match_end(char *str, struct regex *r, int len)
return 0;
}
static int regex_match_glob(char *str, struct regex *r, int len __maybe_unused)
static int regex_match_glob(char *str, struct regex *r, int len)
{
if (glob_match(r->pattern, str))
return 1;
return 0;
return glob_match_len(r->pattern, str, len) ? 1 : 0;
}
/**