[PATCH 4.4 53/54] perf annotate: Use asprintf when formatting objdump command line

Greg Kroah-Hartman
2020-07-30T08:13:26Z

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

commit 6810158d526e483868e519befff407b91e76b3db upstream.

We were using a local buffer with an arbitrary size, that would have to
get increased to avoid truncation as warned by gcc 8:

util/annotate.c: In function 'symbol__disassemble':
util/annotate.c:1488:4: error: '%s' directive output may be truncated writing up to 4095 bytes into a region of size between 3966 and 8086 [-Werror=format-truncation=]
"%s %s%s --start-address=0x%016" PRIx64
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
util/annotate.c:1498:20:
symfs_filename, symfs_filename);
~~~~~~~~~~~~~~
util/annotate.c:1490:50: note: format string is defined here
" -l -d %s %s -C \"%s\" 2>/dev/null|grep -v \"%s:\"|expand",
^~
In file included from /usr/include/stdio.h:861,
from util/color.h:5,
from util/sort.h:8,
from util/annotate.c:14:
/usr/include/bits/stdio2.h:67:10: note: '__builtin___snprintf_chk' output 116 or more bytes (assuming 8331) into a destination of size 8192
return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
__bos (__s), __fmt, __va_arg_pack ());
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

So switch to asprintf, that will make sure enough space is available.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-qagoy2dmbjpc9gdnaj0r3mml@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
tools/perf/util/annotate.c | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)

--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -1077,7 +1077,7 @@ int symbol__annotate(struct symbol *sym,
struct dso *dso = map->dso;
char *filename = dso__build_id_filename(dso, NULL, 0);
bool free_filename = true;
- char command[PATH_MAX * 2];
+ char *command;
FILE *file;
int err = 0;
char symfs_filename[PATH_MAX];
@@ -1192,7 +1192,7 @@ fallback:
strcpy(symfs_filename, tmp);
}

- snprintf(command, sizeof(command),
+ err = asprintf(&command,
"%s %s%s --start-address=0x%016" PRIx64
" --stop-address=0x%016" PRIx64
" -l -d %s %s -C %s 2>/dev/null|grep -v %s|expand",
@@ -1205,6 +1205,11 @@ fallback:
symbol_conf.annotate_src ? "-S" : "",
symfs_filename, filename);

+ if (err < 0) {
+ pr_err("Failure allocating memory for the command to run\n");
+ goto out_remove_tmp;
+ }
+
pr_debug("Executing: %s\n", command);

file = popen(command, "r");
@@ -1214,7 +1219,7 @@ fallback:
* If we were using debug info should retry with
* original binary.
*/
- goto out_remove_tmp;
+ goto out_free_command;
}

nline = 0;
@@ -1237,6 +1242,9 @@ fallback:

pclose(file);

+out_free_command:
+ free(command);
+
out_remove_tmp:
if (dso__needs_decompress(dso))
unlink(symfs_filename);