stash: fix 'show -p' with unknown options

adamchainz · adamchainz · commit 491c0492a9e4 · 2025-05-22T16:18:00.000+01:00
"git stash show -p" with unknown options would fail with a use-after-free
error. This commit fixes that error by ensuring that revision_args has its
argument count updated correctly.

Signed-off-by: Adam Johnson &lt;me@adamj.eu&gt;
diff --git a/builtin/stash.c b/builtin/stash.c
@@ -956,6 +956,7 @@ static int show_stash(int argc, const char **argv, const char *prefix,
 	}
 
 	argc = setup_revisions(revision_args.nr, revision_args.v, &rev, NULL);
+	revision_args.nr = argc;
 	if (argc > 1)
 		goto usage;
 	if (!rev.diffopt.output_format) {
diff --git a/t/t3903-stash.sh b/t/t3903-stash.sh
@@ -699,6 +699,17 @@ test_expect_success 'stash show - stashes on stack, stash-like argument' '
 	test_cmp expected actual
 '
 
+test_expect_success 'stash show -p - stashes on stack, unknown argument shows usage' '
+	git stash clear &&
+	test_when_finished "git reset --hard HEAD" &&
+	git reset --hard &&
+	echo foo >>file &&
+	git stash &&
+	test_when_finished "git stash drop" &&
+	test_expect_code 129 git stash show -p --unknown 2>usage &&
+	grep -F "usage: git stash show" usage
+'
+
 test_expect_success 'stash show -p - stashes on stack, stash-like argument' '
 	git stash clear &&
 	test_when_finished "git reset --hard HEAD" &&

Original file line number	Diff line number	Diff line change
`@@ -956,6 +956,7 @@ static int show_stash(int argc, const char *argv, const char prefix,`
`956`	`956`	`}`
`957`	`957`
`958`	`958`	`argc = setup_revisions(revision_args.nr, revision_args.v, &rev, NULL);`
	`959`	`+ revision_args.nr = argc;`
`959`	`960`	`if (argc > 1)`
`960`	`961`	`goto usage;`
`961`	`962`	`if (!rev.diffopt.output_format) {`