check_packed_git_idx(): check integrity of the idx file itself.

Junio C Hamano · Junio C Hamano · commit c5ced64578a8 · 2005-12-23T14:14:28.000-08:00
Although pack-check.c had routine to verify the checksum for the pack index file itself, the core did not check it before using it. This is stolen from the patch to tighten packname requirements. Signed-off-by: Junio C Hamano <junkio@cox.net> (cherry picked from 797bd6f commit)
diff --git a/sha1_file.c b/sha1_file.c
@@ -321,12 +321,16 @@ struct packed_git *packed_git;
 static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 				void **idx_map_)
 {
+	SHA_CTX ctx;
+	unsigned char sha1[20];
 	void *idx_map;
 	unsigned int *index;
 	unsigned long idx_size;
 	int nr, i;
-	int fd = open(path, O_RDONLY);
+	int fd;
 	struct stat st;
+
+	fd = open(path, O_RDONLY);
 	if (fd < 0)
 		return -1;
 	if (fstat(fd, &st)) {
@@ -364,6 +368,16 @@ static int check_packed_git_idx(const char *path, unsigned long *idx_size_,
 	if (idx_size != 4*256 + nr * 24 + 20 + 20)
 		return error("wrong index file size");
 
+	/*
+	 * File checksum.
+	 */
+	SHA1_Init(&ctx);
+	SHA1_Update(&ctx, idx_map, idx_size-20);
+	SHA1_Final(sha1, &ctx);
+
+	if (memcmp(sha1, idx_map + idx_size - 20, 20))
+		return error("index checksum mismatch");
+
 	return 0;
 }
 
diff --git a/t/t5300-pack-object.sh b/t/t5300-pack-object.sh
@@ -163,6 +163,13 @@ test_expect_success \
      else :;
      fi &&
 
+     cp test-1-${packname_1}.pack test-3.pack &&
+     dd if=/dev/zero of=test-3.idx count=1 bs=1 conv=notrunc seek=1200 &&
+     if git-verify-pack test-3.pack
+     then false
+     else :;
+     fi &&
+
      :'
 
 test_expect_success \
