Make "parse_commit()" be a lot more careful

This was brought on by a bad tree of Thomas Gleixner, where some bogus
commit objects weren't warned about properly

Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/commit.c b/commit.c
index caee5bc218f6db03ec4c8f16f39b892ebb7c762c..d4cd45580def5ed2e0528d95c2a2fa45cb190f23 100644 (file)
--- a/commit.c
+++ b/commit.c
@@ -93,22 +93,28 @@ static unsigned long parse_commit_date(const char *buf)
 
 int parse_commit_buffer(struct commit *item, void *buffer, unsigned long size)
 {
-       void *bufptr = buffer;
+       char *bufptr = buffer;
        unsigned char parent[20];
        struct commit_list **pptr;
 
        if (item->object.parsed)
                return 0;
        item->object.parsed = 1;
-       get_sha1_hex(bufptr + 5, parent);
+       if (memcmp(bufptr, "tree ", 5))
+               return error("bogus commit object %s", sha1_to_hex(item->object.sha1));
+       if (get_sha1_hex(bufptr + 5, parent) < 0)
+               return error("bad tree pointer in commit %s\n", sha1_to_hex(item->object.sha1));
        item->tree = lookup_tree(parent);
        if (item->tree)
                add_ref(&item->object, &item->tree->object);
        bufptr += 46; /* "tree " + "hex sha1" + "\n" */
        pptr = &item->parents;
-       while (!memcmp(bufptr, "parent ", 7) &&
-              !get_sha1_hex(bufptr + 7, parent)) {
-               struct commit *new_parent = lookup_commit(parent);
+       while (!memcmp(bufptr, "parent ", 7)) {
+               struct commit *new_parent;
+
+               if (get_sha1_hex(bufptr + 7, parent) || bufptr[47] != '\n')
+                       return error("bad parents in commit %s", sha1_to_hex(item->object.sha1));
+               new_parent = lookup_commit(parent);
                if (new_parent) {
                        pptr = &commit_list_insert(new_parent, pptr)->next;
                        add_ref(&item->object, &new_parent->object);