[tip: perf/urgent] perf script: Fix invalid read of directory entry after closedir()

[tip-bot2 for Andreas Gerstmayr]

The following commit has been merged into the perf/urgent branch of tip:

Commit-ID:     27486a85cb65bd258a9a213b3e95bdf8c24fd781
Gitweb:        https://git.kernel.org/tip/27486a85cb65bd258a9a213b3e95bdf8c24fd781
Author:        Andreas Gerstmayr <agerstmayr@xxxxxxxxxx>
AuthorDate:    Thu, 02 Apr 2020 14:43:38 +02:00
Committer:     Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitterDate: Fri, 03 Apr 2020 10:03:18 -03:00

perf script: Fix invalid read of directory entry after closedir()

closedir(lang_dir) frees the memory of script_dirent->d_name, which
gets accessed in the next line in a call to scnprintf().

Valgrind report:

  Invalid read of size 1
  ==413557==    at 0x483CBE6: strlen (vg_replace_strmem.c:461)
  ==413557==    by 0x4DD45FD: __vfprintf_internal (vfprintf-internal.c:1688)
  ==413557==    by 0x4DE6679: __vsnprintf_internal (vsnprintf.c:114)
  ==413557==    by 0x53A037: vsnprintf (stdio2.h:80)
  ==413557==    by 0x53A037: scnprintf (vsprintf.c:21)
  ==413557==    by 0x435202: get_script_path (builtin-script.c:3223)
  ==413557==  Address 0x52e7313 is 1,139 bytes inside a block of size 32,816 free'd
  ==413557==    at 0x483AA0C: free (vg_replace_malloc.c:540)
  ==413557==    by 0x4E303C0: closedir (closedir.c:50)
  ==413557==    by 0x4351DC: get_script_path (builtin-script.c:3222)

Signed-off-by: Andreas Gerstmayr <agerstmayr@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lore.kernel.org/lkml/20200402124337.419456-1-agerstmayr@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/builtin-script.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 186ebf8..1f57a7e 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -3265,10 +3265,10 @@ static char *get_script_path(const char *script_root, const char *suffix)
 			__script_root = get_script_root(script_dirent, suffix);
 			if (__script_root && !strcmp(script_root, __script_root)) {
 				free(__script_root);
-				closedir(lang_dir);
 				closedir(scripts_dir);
 				scnprintf(script_path, MAXPATHLEN, "%s/%s",
 					  lang_path, script_dirent->d_name);
+				closedir(lang_dir);
 				return strdup(script_path);
 			}
 			free(__script_root);