maint: check return of split_cmdline to avoid bad config strings

As the testcase demonstrates, it's possible for split_cmdline to return -1 and
deallocate any memory it's allocated, if the config string is missing an end
quote.  In both the cases below, which are the only calling sites, the return
isn't checked, and using the pointer causes a pretty immediate segfault.

Signed-off-by: Deskin Miller <deskinm@umich.edu>
Acked-by: Miklos Vajna <vmiklos@frugalware.org>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

1 files changed, 2 insertions, 0 deletions

diff --git a/builtin-merge.c b/builtin-merge.c
index b280444e10..dcaf3681dc 100644
--- a/builtin-merge.c
+++ b/builtin-merge.c
@@ -442,6 +442,8 @@ static int git_merge_config(const char *k, const char *v, void *cb)
 
 		buf = xstrdup(v);
 		argc = split_cmdline(buf, &argv);
+		if (argc < 0)
+			die("Bad branch.%s.mergeoptions string", branch);
 		argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
 		memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
 		argc++;