[PATCH 16/23] perf tools: Use snprintf() in dso__read_running_kernel_build_id()

[Arnaldo Carvalho de Melo <acme@kernel.org>]

From: Arnaldo Carvalho de Melo <acme@redhat.com>

dso__read_running_kernel_build_id() uses sprintf() to format a sysfs
path from machine->root_dir into a PATH_MAX buffer.  If root_dir is
close to PATH_MAX in length, appending "/sys/kernel/notes" (18 bytes)
overflows the stack buffer.

Switch to snprintf() with sizeof(path) to prevent the overflow.

Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Fixes: cdd059d731eeb466 ("perf tools: Move dso_* related functions into dso object")
Cc: Jiri Olsa <jolsa@kernel.org>
Assisted-by: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/dso.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 6a34717c9f31f18d..5d017975873817ec 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -1779,7 +1779,7 @@ void dso__read_running_kernel_build_id(struct dso *dso, struct machine *machine)
 
 	if (machine__is_default_guest(machine))
 		return;
-	sprintf(path, "%s/sys/kernel/notes", machine->root_dir);
+	snprintf(path, sizeof(path), "%s/sys/kernel/notes", machine->root_dir);
 	sysfs__read_build_id(path, &bid);
 	dso__set_build_id(dso, &bid);
 }
-- 
2.54.0