commit 61dc16bb64b935a7b13342b8bc47db282d10e676
from: Omar Polo <op@omarpolo.com>
via: Thomas Adam <thomas@xteddy.org>
date: Wed May 17 15:49:55 2023 UTC

tog: fix segfault in draw_commit

build_refs_str() can succeed returning a NULL string if a commit
has some refs pointing to it but that were all filtered out, resulting
in a NULL-deref.

ok stsp@

commit - ba77389f9f3a659ebd77c8a4b4974c645e0530fd
commit + 61dc16bb64b935a7b13342b8bc47db282d10e676
blob - 572a730d092394c09f1ea83b262cf72884cc2dac
blob + ff292e9cadc7e6213f828308478d7827b79cb69a
--- tog/tog.c
+++ tog/tog.c
@@ -2405,6 +2405,7 @@ draw_commit(struct tog_view *view, struct got_commit_o
 	struct tog_log_view_state *s = &view->state.log;
 	const struct got_error *err = NULL;
 	char datebuf[12]; /* YYYY-MM-DD + SPACE + NUL */
+	char *refs_str = NULL;
 	char *logmsg0 = NULL, *logmsg = NULL;
 	char *author = NULL;
 	wchar_t *wlogmsg = NULL, *wauthor = NULL;
@@ -2499,13 +2500,13 @@ draw_commit(struct tog_view *view, struct got_commit_o
 
 	/* Prepend reference labels to log message if possible .*/
 	refs = got_reflist_object_id_map_lookup(tog_refs_idmap, id);
-	if (refs) {
-		char *refs_str, *newlogmsg;
-		wchar_t *ws;
-
+	if (refs)
 		err = build_refs_str(&refs_str, refs, id, s->repo);
-		if (err)
-			goto done;
+	if (err)
+		goto done;
+	if (refs_str) {
+		char *newlogmsg;
+		wchar_t *ws;
 	
 		/*
 		 * The length of this wide-char sub-string will be
@@ -2520,10 +2521,8 @@ draw_commit(struct tog_view *view, struct got_commit_o
 
 		if (asprintf(&newlogmsg, "[%s] %s", refs_str, logmsg) == -1) {
 			err = got_error_from_errno("asprintf");
-			free(refs_str);
 			goto done;
 		}
-		free(refs_str);
 
 		free(logmsg0);
 		logmsg0 = newlogmsg;
@@ -2558,6 +2557,7 @@ draw_commit(struct tog_view *view, struct got_commit_o
 done:
 	free(logmsg0);
 	free(wlogmsg);
+	free(refs_str);
 	free(author);
 	free(wauthor);
 	free(line);