| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 262/293] perf annotate: Fix dereferencing freed memory found by the smatch tool | Date | Mon, 29 Jul 2019 21:22:33 +0200 |
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[ Upstream commit 600c787dbf6521d8d07ee717ab7606d5070103ea ]
Based on the following report from Smatch, fix the potential dereferencing freed memory check.
tools/perf/util/annotate.c:1125 disasm_line__parse() error: dereferencing freed memory 'namep'
tools/perf/util/annotate.c 1100 static int disasm_line__parse(char *line, const char **namep, char **rawp) 1101 { 1102 char tmp, *name = ltrim(line);
[...]
1114 *namep = strdup(name); 1115 1116 if (*namep == NULL) 1117 goto out_free_name;
[...]
1124 out_free_name: 1125 free((void *)namep); ^^^^^ 1126 *namep = NULL; ^^^^^^ 1127 return -1; 1128 }
If strdup() fails to allocate memory space for *namep, we don't need to free memory with pointer 'namep', which is resident in data structure disasm_line::ins::name; and *namep is NULL pointer for this failure, so it's pointless to assign NULL to *namep again.
Committer note:
Freeing namep, which is the address of the first entry of the 'struct ins' that is the first member of struct disasm_line would in fact free that disasm_line instance, if it was allocated via malloc/calloc, which, later, would a dereference of freed memory.
Signed-off-by: Leo Yan <leo.yan@linaro.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: Alexios Zavras <alexios.zavras@intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Changbin Du <changbin.du@intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Eric Saint-Etienne <eric.saint.etienne@oracle.com> Cc: Jin Yao <yao.jin@linux.intel.com> Cc: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Song Liu <songliubraving@fb.com> Cc: Suzuki Poulouse <suzuki.poulose@arm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Richter <tmricht@linux.ibm.com> Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/20190702103420.27540-5-leo.yan@linaro.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org> --- tools/perf/util/annotate.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c index 398d4cc2f0e4..2a8d2a6723f6 100644 --- a/tools/perf/util/annotate.c +++ b/tools/perf/util/annotate.c @@ -868,16 +868,14 @@ static int disasm_line__parse(char *line, const char **namep, char **rawp) *namep = strdup(name); if (*namep == NULL) - goto out_free_name; + goto out; (*rawp)[0] = tmp; *rawp = ltrim(*rawp); return 0; -out_free_name: - free((void *)namep); - *namep = NULL; +out: return -1; } -- 2.20.1
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