This makes write_ref_sha1() more careful: it actually checks the SHA1 of
the ref it is updating, and refuses to update a ref with an object that it
cannot find.
Perhaps more importantly, it also refuses to update a branch head with a
non-commit object. I don't quite know *how* the stable series maintainers
were able to corrupt their repository to have a HEAD that pointed to a tag
rather than a commit object, but they did. Which results in a totally
broken repository that cannot be cloned or committed on.
So make it harder for people to shoot themselves in the foot like that.
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
---
I'm signing off on this, but I hope people will double-check this: I
didn't actually test it very much.
refs.c | 19 +++++++++++++++++++
1 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/refs.c b/refs.c
index 58f6d17..c3ffe03 100644
--- a/refs.c
+++ b/refs.c
@@ -1119,10 +1119,16 @@ static int log_ref_write(const char *ref_name, const unsigned char *old_sha1,
return 0;
}
+static int is_branch(const char *refname)
+{
+ return !strcmp(refname, "HEAD") || !prefixcmp(refname, "refs/heads/");
+}
+
int write_ref_sha1(struct ref_lock *lock,
const unsigned char *sha1, const char *logmsg)
{
static char term = '\n';
+ struct object *o;
if (!lock)
return -1;
@@ -1130,6 +1136,19 @@ int write_ref_sha1(struct ref_lock *lock,
unlock_ref(lock);
return 0;
}
+ o = parse_object(sha1);
+ if (!o) {
+ error("Trying to write ref %s with nonexistant object %s",
+ lock->ref_name, sha1_to_hex(sha1));
+ unlock_ref(lock);
+ return -1;
+ }
+ if (o->type != OBJ_COMMIT && is_branch(lock->ref_name)) {
+ error("Trying to write non-commit object %s to branch %s",
+ sha1_to_hex(sha1), lock->ref_name);
+ unlock_ref(lock);
+ return -1;
+ }
if (write_in_full(lock->lock_fd, sha1_to_hex(sha1), 40) != 40 ||
write_in_full(lock->lock_fd, &term, 1) != 1
|| close(lock->lock_fd) < 0) {
-
To unsubscribe from this list: send the line "unsubscribe git" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
