[PATCH v2 16/27] help: fix leaking return value from `help_unknown_cmd()`
- From
Patrick Steinhardt <ps@pks.im>
- Date
- Nov 11, 2024, 10:38 UTC
- Message-ID
- <20241111-b4-pks-leak-fixes-pt10-v2-16-6154bf91f0b0@pks.im>
- In-Reply-To
- <20241111-b4-pks-leak-fixes-pt10-v2-0-6154bf91f0b0@pks.im>
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> --- git.c | 4 +++- help.c | 7 +++---- help.h | 2 +- 3 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/git.c b/git.c index 159dd45b08204c4a89d1dc4ab6990978e2454eb6..46b3c740c5d665388917c6eee3052cc3ef8368f2 100644 --- a/git.c +++ b/git.c @@ -961,7 +961,9 @@ int cmd_main(int argc, const char **argv) exit(1); } if (!done_help) { - strvec_replace(&args, 0, help_unknown_cmd(cmd)); + char *assumed = help_unknown_cmd(cmd); + strvec_replace(&args, 0, assumed); + free(assumed); cmd = args.v[0]; done_help = 1; } else { diff --git a/help.c b/help.c index 8b56cd6e25ba5f2be2cbf2a7a9ed48136e12a0c7..8a830ba35c6fd1377213e2ed40846f3d46dba363 100644 --- a/help.c +++ b/help.c @@ -612,7 +612,7 @@ static const char bad_interpreter_advice[] = N_("'%s' appears to be a git command, but we were not\n" "able to execute it. Maybe git-%s is broken?"); -const char *help_unknown_cmd(const char *cmd) +char *help_unknown_cmd(const char *cmd) { struct help_unknown_cmd_config cfg = { 0 }; int i, n, best_similarity = 0; @@ -695,9 +695,8 @@ const char *help_unknown_cmd(const char *cmd) ; /* still counting */ } if (cfg.autocorrect && n == 1 && SIMILAR_ENOUGH(best_similarity)) { - const char *assumed = main_cmds.names[0]->name; - main_cmds.names[0] = NULL; - cmdnames_release(&main_cmds); + char *assumed = xstrdup(main_cmds.names[0]->name); + fprintf_ln(stderr, _("WARNING: You called a Git command named '%s', " "which does not exist."), diff --git a/help.h b/help.h index e716ee27ea174c4dfc3b941619bf361972894212..67207b3073ce48fa25f67f9a4922abc4e2ce7926 100644 --- a/help.h +++ b/help.h @@ -32,7 +32,7 @@ void list_all_other_cmds(struct string_list *list); void list_cmds_by_category(struct string_list *list, const char *category); void list_cmds_by_config(struct string_list *list); -const char *help_unknown_cmd(const char *cmd); +char *help_unknown_cmd(const char *cmd); void load_command_list(const char *prefix, struct cmdnames *main_cmds, struct cmdnames *other_cmds);
-- 2.47.0.229.g8f8d6eee53.dirty