@matheusbsbs / matheus-bagliano / commits / 2b2999460c

builtin/for-each-repo: remove unnecessary argv copy to plug leak

cmd_for_each_repo() copies argv into args (a strvec), which is later passed into run_command_on_repo(), which in turn copies that strvec onto the end of child.args. The initial copy is unnecessary (we never modify args). We therefore choose to just pass argv directly into run_command_on_repo(), which lets us avoid the copy and fixes the leak. LSAN output from t0068: Direct leak of 192 byte(s) in 1 object(s) allocated from: #0 0x7f63bd4ab8b0 in realloc (/usr/lib64/libasan.so.4+0xdc8b0) #1 0x98d7e6 in xrealloc wrapper.c:126 #2 0x916914 in strvec_push_nodup strvec.c:19 #3 0x916a6e in strvec_push strvec.c:26 #4 0x4be4eb in cmd_for_each_repo builtin/for-each-repo.c:49 #5 0x410dcd in run_builtin git.c:475 #6 0x410dcd in handle_builtin git.c:729 #7 0x414087 in run_argv git.c:818 #8 0x414087 in cmd_main git.c:949 #9 0x40e9ec in main common-main.c:52 #10 0x7f63bc9fa349 in __libc_start_main (/lib64/libc.so.6+0x24349) Indirect leak of 22 byte(s) in 2 object(s) allocated from: #0 0x7f63bd445e30 in __interceptor_strdup (/usr/lib64/libasan.so.4+0x76e30) #1 0x98d698 in xstrdup wrapper.c:29 #2 0x916a63 in strvec_push strvec.c:26 #3 0x4be4eb in cmd_for_each_repo builtin/for-each-repo.c:49 #4 0x410dcd in run_builtin git.c:475 #5 0x410dcd in handle_builtin git.c:729 #6 0x414087 in run_argv git.c:818 #7 0x414087 in cmd_main git.c:949 #8 0x40e9ec in main common-main.c:52 #9 0x7f63bc9fa349 in __libc_start_main (/lib64/libc.so.6+0x24349) See also discussion about the original implementation below - this code appears to have evolved from a callback explaining the double-strvec-copy pattern, but there's no strong reason to keep that now: https://lore.kernel.org/git/68bbeca5-314b-08ee-ef36-040e3f3814e9@gmail.com/ Signed-off-by: Andrzej Hunt <andrzej@ahunt.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Andrzej Hunt committed Jul 25, 2021 at 15:08 UTC 2b2999460c7e907dc80593483e1c23ce00b6745c

1 file changed +4 -10

builtin/for-each-repo.c

+4 -10

@@ -10,18 +10,16 @@ static const char * const for_each_repo_usage[] = {

10 NULL

11 };

13 -static int run_command_on_repo(const char *path,

14 - void *cbdata)

13 +static int run_command_on_repo(const char *path, int argc, const char ** argv)

14 {

15 int i;

16 struct child_process child = CHILD_PROCESS_INIT;

18 - struct strvec *args = (struct strvec *)cbdata;

18 child.git_cmd = 1;

19 strvec_pushl(&child.args, "-C", path, NULL);

23 - for (i = 0; i < args->nr; i++)

24 - strvec_push(&child.args, args->v[i]);

21 + for (i = 0; i < argc; i++)

22 + strvec_push(&child.args, argv[i]);

24 return run_command(&child);

25 }

@@ -31,7 +29,6 @@ int cmd_for_each_repo(int argc, const char **argv, const char *prefix)

29 static const char *config_key = NULL;

30 int i, result = 0;

31 const struct string_list *values;

34 - struct strvec args = STRVEC_INIT;

33 const struct option options[] = {

34 OPT_STRING(0, "config", &config_key, N_("config"),

@@ -45,9 +42,6 @@ int cmd_for_each_repo(int argc, const char **argv, const char *prefix)

42 if (!config_key)

43 die(_("missing --config=<config>"));

48 - for (i = 0; i < argc; i++)

49 - strvec_push(&args, argv[i]);

50 -

45 values = repo_config_get_value_multi(the_repository,

46 config_key);

@@ -59,7 +53,7 @@ int cmd_for_each_repo(int argc, const char **argv, const char *prefix)

53 return 0;

55 for (i = 0; !result && i < values->nr; i++)

62 - result = run_command_on_repo(values->items[i].string, &args);

56 + result = run_command_on_repo(values->items[i].string, argc, argv);

58 return result;

59 }