Re: [PATCH 1/2] apply: guard against renames of non-existant empty files

["René Scharfe" <l.s.r@web.de>]

Am 27.02.2017 um 23:18 schrieb René Scharfe:
> Am 27.02.2017 um 21:10 schrieb Junio C Hamano:
>> René Scharfe <l.s.r@web.de> writes:
>>
>>> Would it make sense to mirror the previously existing condition and
>>> check for is_new instead?  I.e.:
>>>
>>>             if ((!patch->is_delete && !patch->new_name) ||
>>>                 (!patch->is_new    && !patch->old_name)) {
>>>
>>
>> Yes, probably.

So let's actually do it!

-- >8 --
Subject: [PATCH] apply: check git diffs for missing old filenames

2c93286a (fix "git apply --index ..." not to deref NULL) added a check
for git patches missing a +++ line, preventing a segfault.  Check for
missing --- lines as well, and add a test for each case.

Found by Vegard Nossum using AFL.

Original-patch-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Rene Scharfe <l.s.r@web.de>
---
 apply.c                    |  3 ++-
 t/t4133-apply-filenames.sh | 24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/apply.c b/apply.c
index b963d7d8fb..8cd6435c74 100644
--- a/apply.c
+++ b/apply.c
@@ -1575,7 +1575,8 @@ static int find_header(struct apply_state *state,
 				patch->old_name = xstrdup(patch->def_name);
 				patch->new_name = xstrdup(patch->def_name);
 			}
-			if (!patch->is_delete && !patch->new_name) {
+			if ((!patch->new_name && !patch->is_delete) ||
+			    (!patch->old_name && !patch->is_new)) {
 				error(_("git diff header lacks filename information "
 					     "(line %d)"), state->linenr);
 				return -128;
diff --git a/t/t4133-apply-filenames.sh b/t/t4133-apply-filenames.sh
index 2ecb4216b7..c5ed3b17c4 100755
--- a/t/t4133-apply-filenames.sh
+++ b/t/t4133-apply-filenames.sh
@@ -35,4 +35,28 @@ test_expect_success 'apply diff with inconsistent filenames in headers' '
 	test_i18ngrep "inconsistent old filename" err
 '
 
+test_expect_success 'apply diff with new filename missing from headers' '
+	cat >missing_new_filename.diff <<-\EOF &&
+	diff --git a/f b/f
+	index 0000000..d00491f
+	--- a/f
+	@@ -0,0 +1 @@
+	+1
+	EOF
+	test_must_fail git apply missing_new_filename.diff 2>err &&
+	test_i18ngrep "lacks filename information" err
+'
+
+test_expect_success 'apply diff with old filename missing from headers' '
+	cat >missing_old_filename.diff <<-\EOF &&
+	diff --git a/f b/f
+	index d00491f..0000000
+	+++ b/f
+	@@ -1 +0,0 @@
+	-1
+	EOF
+	test_must_fail git apply missing_old_filename.diff 2>err &&
+	test_i18ngrep "lacks filename information" err
+'
+
 test_done
-- 
2.13.2