fsck-cache: fix segfault on nonexistent referenced object

Noted by Frank Sorenson and Petr Baudis, patch rewritten by me.

diff --git a/fsck-cache.c b/fsck-cache.c
index 32fa5d5..6c65f2b 100644 (file)
--- a/fsck-cache.c
+++ b/fsck-cache.c
@@ -296,7 +296,7 @@ static int fsck_dir(int i, char *path)
        return 0;
 }
 
-static void read_sha1_reference(const char *path)
+static int read_sha1_reference(const char *path)
 {
        char hexname[60];
        unsigned char sha1[20];
@@ -304,19 +304,23 @@ static void read_sha1_reference(const char *path)
        struct object *obj;
 
        if (fd < 0)
-               return;
+               return -1;
 
        len = read(fd, hexname, sizeof(hexname));
        close(fd);
        if (len < 40)
-               return;
+               return -1;
 
        if (get_sha1_hex(hexname, sha1) < 0)
-               return;
+               return -1;
 
        obj = lookup_object(sha1);
+       if (!obj)
+               return error("%s: invalid sha1 pointer %.40s", path, hexname);
+
        obj->used = 1;
        mark_reachable(obj, REACHABLE);
+       return 0;
 }
 
 static void find_file_objects(const char *base, const char *name)