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Subject[PATCH 07/23] perf map: Fix off by one in strncpy() size argument
From: disconnect3d <>

This patch fixes an off-by-one error in strncpy size argument in
tools/perf/util/map.c. The issue is that in:

strncmp(filename, "/system/lib/", 11)

the passed string literal: "/system/lib/" has 12 bytes (without the NULL
byte) and the passed size argument is 11. As a result, the logic won't
match the ending "/" byte and will pass filepaths that are stored in
other directories e.g. "/system/libmalicious/bin" or just

This functionality seems to be present only on Android. I assume the
/system/ directory is only writable by the root user, so I don't think
this bug has much (or any) security impact.

Fixes: eca818369996 ("perf tools: Add automatic remapping of Android libraries")
Signed-off-by: disconnect3d <>
Cc: Alexander Shishkin <>
Cc: Changbin Du <>
Cc: Jiri Olsa <>
Cc: John Keeping <>
Cc: Mark Rutland <>
Cc: Michael Lentine <>
Cc: Namhyung Kim <>
Cc: Peter Zijlstra <>
Cc: Song Liu <>
Cc: Stephane Eranian <>
Signed-off-by: Arnaldo Carvalho de Melo <>
tools/perf/util/map.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 95428511300d..b342f744b1fc 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -89,7 +89,7 @@ static inline bool replace_android_lib(const char *filename, char *newfilename)
return true;

- if (!strncmp(filename, "/system/lib/", 11)) {
+ if (!strncmp(filename, "/system/lib/", 12)) {
char *ndk, *app;
const char *arch;
size_t ndk_length;
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