@matheusbsbs / matheus-bagliano / commits / 7720dbe99b

help: fix leaking return value from `help_unknown_cmd()`

While `help_unknown_cmd()` would usually die on an unknown command, it instead returns an autocorrected command when "help.autocorrect" is set. But while the function is declared to return a string constant, it actually returns an allocated string in that case. Callers thus aren't aware that they have to free the string, leading to a memory leak. Fix the function return type to be non-constant and free the returned value at its only callsite. Note that we cannot simply take ownership of `main_cmds.names[0]->name` and then eventually free it. This is because the `struct cmdname` is using a flex array to allocate the name, so the name pointer points into the middle of the structure and thus cannot be freed. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Patrick Steinhardt committed Nov 20, 2024 at 14:39 UTC 7720dbe99b303b3d658898587e02d7cf224a93c3

3 files changed +7 -6

git.c

+3 -1

@@ -961,7 +961,9 @@ int cmd_main(int argc, const char **argv)

961 exit(1);

962 }

963 if (!done_help) {

964 - strvec_replace(&args, 0, help_unknown_cmd(cmd));

964 + char *assumed = help_unknown_cmd(cmd);

965 + strvec_replace(&args, 0, assumed);

966 + free(assumed);

967 cmd = args.v[0];

968 done_help = 1;

969 } else {

help.c

+3 -4

@@ -612,7 +612,7 @@ static const char bad_interpreter_advice[] =

612 N_("'%s' appears to be a git command, but we were not\n"

613 "able to execute it. Maybe git-%s is broken?");

614

615 -const char *help_unknown_cmd(const char *cmd)

615 +char *help_unknown_cmd(const char *cmd)

616 {

617 struct help_unknown_cmd_config cfg = { 0 };

618 int i, n, best_similarity = 0;

@@ -695,9 +695,8 @@ const char *help_unknown_cmd(const char *cmd)

695 ; /* still counting */

696 }

697 if (cfg.autocorrect && n == 1 && SIMILAR_ENOUGH(best_similarity)) {

698 - const char *assumed = main_cmds.names[0]->name;

699 - main_cmds.names[0] = NULL;

700 - cmdnames_release(&main_cmds);

698 + char *assumed = xstrdup(main_cmds.names[0]->name);

699 +

700 fprintf_ln(stderr,

701 _("WARNING: You called a Git command named '%s', "

702 "which does not exist."),

help.h

+1 -1

@@ -32,7 +32,7 @@ void list_all_other_cmds(struct string_list *list);

32 void list_cmds_by_category(struct string_list *list,

33 const char *category);

34 void list_cmds_by_config(struct string_list *list);

35 -const char *help_unknown_cmd(const char *cmd);

35 +char *help_unknown_cmd(const char *cmd);

36 void load_command_list(const char *prefix,

37 struct cmdnames *main_cmds,

38 struct cmdnames *other_cmds);