apply: don't segfault on binary files with missing data

Usually when applying a binary diff generated without
--binary, it will be rejected early, as we don't even have
the full sha1 of the pre- and post-images.

However, if the diff is generated with --full-index (but not
--binary), then we will actually try to apply it. If we have
the postimage blob, then we can take a shortcut and never
even look at the binary diff at all (e.g., this can happen
when rebasing changes within a repository).

If we don't have the postimage blob, though, we try to look
at the actual fragments, of which there are none, and get a
segfault. This patch checks explicitly for that case and
complains to the user instead of segfaulting. We need to
keep the check at a low level so that the "shortcut" case
above continues to work.

We also add a test that demonstrates the segfault. While
we're at it, let's also explicitly test the shortcut case.

Reported-by: Rafaël Carré <rafael.carre@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/apply.c b/builtin/apply.c
index 23c18c573b9147b7aaa88a8d1d2f26748e803501..f051e66dcc5260e4e7ecb28c36e2c6da8e823d6b 100644 (file)
--- a/builtin/apply.c
+++ b/builtin/apply.c
@@ -2645,6 +2645,12 @@ static int apply_binary_fragment(struct image *img, struct patch *patch)
        unsigned long len;
        void *dst;
 
+       if (!fragment)
+               return error("missing binary patch data for '%s'",
+                            patch->new_name ?
+                            patch->new_name :
+                            patch->old_name);
+
        /* Binary patch is irreversible without the optional second hunk */
        if (apply_in_reverse) {
                if (!fragment->next)

diff --git a/t/t4103-apply-binary.sh b/t/t4103-apply-binary.sh
index 9692f16f3581f261c4c10a29f03751990adb7897..08ad6d8b9e6b2869bfd2b574779380895709972d 100755 (executable)
--- a/t/t4103-apply-binary.sh
+++ b/t/t4103-apply-binary.sh
@@ -37,7 +37,16 @@ test_expect_success 'setup' "
        git diff-tree -p -C master binary >C.diff &&
 
        git diff-tree -p --binary master binary >BF.diff &&
-       git diff-tree -p --binary -C master binary >CF.diff
+       git diff-tree -p --binary -C master binary >CF.diff &&
+
+       git diff-tree -p --full-index master binary >B-index.diff &&
+       git diff-tree -p -C --full-index master binary >C-index.diff &&
+
+       git init other-repo &&
+       (cd other-repo &&
+        git fetch .. master &&
+        git reset --hard FETCH_HEAD
+       )
 "
 
 test_expect_success 'stat binary diff -- should not fail.' \
@@ -100,6 +109,22 @@ test_expect_success 'apply binary diff (copy) -- should fail.' \
        'do_reset &&
         test_must_fail git apply --index C.diff'
 
+test_expect_success 'apply binary diff with full-index' '
+       do_reset &&
+       git apply B-index.diff
+'
+
+test_expect_success 'apply binary diff with full-index (copy)' '
+       do_reset &&
+       git apply C-index.diff
+'
+
+test_expect_success 'apply full-index binary diff in new repo' '
+       (cd other-repo &&
+        do_reset &&
+        test_must_fail git apply ../B-index.diff)
+'
+
 test_expect_success 'apply binary diff without replacement.' \
        'do_reset &&
         git apply BF.diff'