[PATCH] receive-pack: reject invalid refnames

[PATCH] receive-pack: reject invalid refnames

[Martin Koegler]

Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at>
---
 receive-pack.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/receive-pack.c b/receive-pack.c
index d0a563d..a038a40 100644
--- a/receive-pack.c
+++ b/receive-pack.c
@@ -165,7 +165,9 @@ static const char *update(struct command *cmd)
 	unsigned char *new_sha1 = cmd->new_sha1;
 	struct ref_lock *lock;
 
-	if (!prefixcmp(name, "refs/") && check_ref_format(name + 5)) {
+	/* only HEAD and refs/... are allowed */
+	if (strcmp(name, "HEAD") && 
+	    (prefixcmp(name, "refs/") || check_ref_format(name + 5))) {
 		error("refusing to create funny ref '%s' remotely", name);
 		return "funny refname";
 	}
@@ -177,7 +179,8 @@ static const char *update(struct command *cmd)
 	}
 	if (deny_non_fast_forwards && !is_null_sha1(new_sha1) &&
 	    !is_null_sha1(old_sha1) &&
-	    !prefixcmp(name, "refs/heads/")) {
+	    (!prefixcmp(name, "refs/heads/") ||
+	     !strcmp(name, "HEAD"))) {
 		struct object *old_object, *new_object;
 		struct commit *old_commit, *new_commit;
 		struct commit_list *bases, *ent;
-- 
1.4.4.4

Re: [PATCH] receive-pack: reject invalid refnames

[Junio C Hamano]

Martin Koegler <mkoegler@auto.tuwien.ac.at> writes:

> Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at>
> ---
>  receive-pack.c |    7 +++++--
>  1 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/receive-pack.c b/receive-pack.c
> index d0a563d..a038a40 100644
> --- a/receive-pack.c
> +++ b/receive-pack.c
> @@ -165,7 +165,9 @@ static const char *update(struct command *cmd)
>  	unsigned char *new_sha1 = cmd->new_sha1;
>  	struct ref_lock *lock;
>  
> -	if (!prefixcmp(name, "refs/") && check_ref_format(name + 5)) {
> +	/* only HEAD and refs/... are allowed */
> +	if (strcmp(name, "HEAD") && 
> +	    (prefixcmp(name, "refs/") || check_ref_format(name + 5))) {
>  		error("refusing to create funny ref '%s' remotely", name);
>  		return "funny refname";
>  	}
> @@ -177,7 +179,8 @@ static const char *update(struct command *cmd)
>  	}
>  	if (deny_non_fast_forwards && !is_null_sha1(new_sha1) &&
>  	    !is_null_sha1(old_sha1) &&
> -	    !prefixcmp(name, "refs/heads/")) {
> +	    (!prefixcmp(name, "refs/heads/") ||
> +	     !strcmp(name, "HEAD"))) {
>  		struct object *old_object, *new_object;
>  		struct commit *old_commit, *new_commit;
>  		struct commit_list *bases, *ent;

Yuck.  What I was smoking.

Normal client "git push" does not even allow "git push victim
foo:HEAD".  So if name is "HEAD" that has to be a malicious
crafted push.

I think 

	if (prefixcmp(name, "refs/") || check_ref_format(name + 5))
		error();

is enough and correct.

Sorry for my earlier thinko.

[PATCH] receive-pack: reject invalid refnames

[Martin Koegler]

Signed-off-by: Martin Koegler <mkoegler@auto.tuwien.ac.at>
---
 receive-pack.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/receive-pack.c b/receive-pack.c
index d0a563d..3267495 100644
--- a/receive-pack.c
+++ b/receive-pack.c
@@ -165,7 +165,8 @@ static const char *update(struct command *cmd)
 	unsigned char *new_sha1 = cmd->new_sha1;
 	struct ref_lock *lock;
 
-	if (!prefixcmp(name, "refs/") && check_ref_format(name + 5)) {
+	/* only refs/... are allowed */
+	if (prefixcmp(name, "refs/") || check_ref_format(name + 5)) {
 		error("refusing to create funny ref '%s' remotely", name);
 		return "funny refname";
 	}
-- 
1.4.4.4