@matheusbsbs / matheus-bagliano / commits / f046127b66

ref-filter: fix leak when formatting %(push:remoteref)

When we expand the %(upstream) or %(push) placeholders, we rely on remote.c's remote_ref_for_branch() to fill in the ":refname" argument. But that function has confusing memory ownership semantics: it may or may not return an allocated string, depending on whether we are in "upstream" mode or "push" mode. The caller in ref-filter.c always duplicates the result, meaning that we leak the original in the case of %(push:refname). To solve this, let's make the return value from remote_ref_for_branch() consistent, by always returning an allocated pointer. Note that the switch to returning a non-const pointer has a ripple effect inside the function, too. We were storing the "dst" result as a const pointer, too, even though it is always allocated! It is the return value from apply_refspecs(), which is always a non-const allocated string. And then on the caller side in ref-filter.c (and this is the only caller at all), we just need to avoid the extra duplication when the return value is non-NULL. This clears up one case that LSan finds in t6300, but there are more. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Jeff King committed Sep 9, 2024 at 19:19 UTC f046127b6682f98d41bb4d26164da7f1a4a8e8d0
3 files changed +6 -6
ref-filter.c
+1 -1
index 370cc5b44a..0f51095bbd 100644 --- a/ref-filter.c +++ b/ref-filter.c @@ -2237,7 +2237,7 @@ static void fill_remote_ref_details(struct used_atom *atom, const char *refname, const char *merge; merge = remote_ref_for_branch(branch, atom->u.remote_ref.push); - *s = xstrdup(merge ? merge : ""); + *s = merge ? merge : xstrdup(""); } else BUG("unhandled RR_* enum"); }
remote.c
+4 -4
index 8f3dee1318..539e5ceae3 100644 --- a/remote.c +++ b/remote.c @@ -632,7 +632,7 @@ const char *pushremote_for_branch(struct branch *branch, int *explicit) static struct remote *remotes_remote_get(struct remote_state *remote_state, const char *name); -const char *remote_ref_for_branch(struct branch *branch, int for_push) +char *remote_ref_for_branch(struct branch *branch, int for_push) { read_config(the_repository, 0); die_on_missing_branch(the_repository, branch); @@ -640,11 +640,11 @@ const char *remote_ref_for_branch(struct branch *branch, int for_push) if (branch) { if (!for_push) { if (branch->merge_nr) { - return branch->merge_name[0]; + return xstrdup(branch->merge_name[0]); } } else { - const char *dst, - *remote_name = remotes_pushremote_for_branch( + char *dst; + const char *remote_name = remotes_pushremote_for_branch( the_repository->remote_state, branch, NULL); struct remote *remote = remotes_remote_get(
remote.h
+1 -1
index b901b56746..a58713f20a 100644 --- a/remote.h +++ b/remote.h @@ -329,7 +329,7 @@ struct branch { struct branch *branch_get(const char *name); const char *remote_for_branch(struct branch *branch, int *explicit); const char *pushremote_for_branch(struct branch *branch, int *explicit); -const char *remote_ref_for_branch(struct branch *branch, int for_push); +char *remote_ref_for_branch(struct branch *branch, int for_push); /* returns true if the given branch has merge configuration given. */ int branch_has_merge_config(struct branch *branch);