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mirror of https://github.com/git/git synced 2024-07-02 15:48:44 +00:00

Be more careful about updating refs

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.

The test t1400-update-ref.sh is fixed at the same time, as it
assumed that the commands involved in the particular test would
not care about corrupted repositories whose refs point at
nonexistant bogus objects.  That assumption does not hold true
anymore.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Linus Torvalds 2008-01-15 15:50:17 -08:00 committed by Junio C Hamano
parent 9f6fe82233
commit c3b0dec509
2 changed files with 32 additions and 6 deletions

19
refs.c
View File

@ -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) {

View File

@ -7,12 +7,19 @@ test_description='Test git update-ref and basic ref logging'
. ./test-lib.sh
Z=0000000000000000000000000000000000000000
A=1111111111111111111111111111111111111111
B=2222222222222222222222222222222222222222
C=3333333333333333333333333333333333333333
D=4444444444444444444444444444444444444444
E=5555555555555555555555555555555555555555
F=6666666666666666666666666666666666666666
test_expect_success setup '
for name in A B C D E F
do
test_tick &&
T=$(git write-tree) &&
sha1=$(echo $name | git commit-tree $T) &&
eval $name=$sha1
done
'
m=refs/heads/master
n_dir=refs/heads/gu
n=$n_dir/fixes