read_packed_refs(): die if packed-refs contains bogus data

The old code ignored any lines that it didn't understand, including
unterminated lines. This is dangerous. Instead, `die()` if the
`packed-refs` file contains any unterminated lines or lines that we
don't know how to handle.

This fixes the tests added in the last commit.

Signed-off-by: Michael Haggerty <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: mhagger

refs/packed-backend.c

@@ -230,6 +230,9 @@ static struct packed_ref_cache *read_packed_refs(const char *packed_refs_file)
 		const char *refname;
 		const char *traits;
 
+		if (!line.len || line.buf[line.len - 1] != '\n')
+			die("unterminated line in %s: %s", packed_refs_file, line.buf);
+
 		if (skip_prefix(line.buf, "# pack-refs with:", &traits)) {
 			if (strstr(traits, " fully-peeled "))
 				peeled = PEELED_FULLY;
@@ -254,9 +257,7 @@ static struct packed_ref_cache *read_packed_refs(const char *packed_refs_file)
 			    (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
 				last->flag |= REF_KNOWS_PEELED;
 			add_ref_entry(dir, last);
-			continue;
-		}
-		if (last &&
+		} else if (last &&
 		    line.buf[0] == '^' &&
 		    line.len == PEELED_LINE_LENGTH &&
 		    line.buf[PEELED_LINE_LENGTH - 1] == '\n' &&
@@ -268,6 +269,9 @@ static struct packed_ref_cache *read_packed_refs(const char *packed_refs_file)
 			 * reference:
 			 */
 			last->flag |= REF_KNOWS_PEELED;
+		} else {
+			strbuf_setlen(&line, line.len - 1);
+			die("unexpected line in %s: %s", packed_refs_file, line.buf);
 		}
 	}
 

t/t3210-pack-refs.sh

@@ -194,7 +194,7 @@ test_expect_success 'notice d/f conflict with existing ref' '
 	test_must_fail git branch foo/bar/baz/lots/of/extra/components
 '
 
-test_expect_failure 'reject packed-refs with unterminated line' '
+test_expect_success 'reject packed-refs with unterminated line' '
 	cp .git/packed-refs .git/packed-refs.bak &&
 	test_when_finished "mv .git/packed-refs.bak .git/packed-refs" &&
 	printf "%s" "$HEAD refs/zzzzz" >>.git/packed-refs &&
@@ -203,7 +203,7 @@ test_expect_failure 'reject packed-refs with unterminated line' '
 	test_cmp expected_err err
 '
 
-test_expect_failure 'reject packed-refs containing junk' '
+test_expect_success 'reject packed-refs containing junk' '
 	cp .git/packed-refs .git/packed-refs.bak &&
 	test_when_finished "mv .git/packed-refs.bak .git/packed-refs" &&
 	printf "%s\n" "bogus content" >>.git/packed-refs &&
@@ -212,7 +212,7 @@ test_expect_failure 'reject packed-refs containing junk' '
 	test_cmp expected_err err
 '
 
-test_expect_failure 'reject packed-refs with a short SHA-1' '
+test_expect_success 'reject packed-refs with a short SHA-1' '
 	cp .git/packed-refs .git/packed-refs.bak &&
 	test_when_finished "mv .git/packed-refs.bak .git/packed-refs" &&
 	printf "%.7s %s\n" $HEAD refs/zzzzz >>.git/packed-refs &&