From: Shi Weihua <shiwh@cn.fujitsu.com>
Date: Tue, 18 May 2010 00:50:32 +0000 (+0000)
Subject: Btrfs: should add a permission check for setfacl
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=2f26afba46f0ebf155cf9be746496a0304a5b7cf;p=linux-beck.git

Btrfs: should add a permission check for setfacl

On btrfs, do the following
------------------
# su user1
# cd btrfs-part/
# touch aaa
# getfacl aaa
  # file: aaa
  # owner: user1
  # group: user1
  user::rw-
  group::rw-
  other::r--
# su user2
# cd btrfs-part/
# setfacl -m u::rwx aaa
# getfacl aaa
  # file: aaa
  # owner: user1
  # group: user1
  user::rwx           <- successed to setfacl
  group::rw-
  other::r--
------------------
but we should prohibit it that user2 changing user1's acl.
In fact, on ext3 and other fs, a message occurs:
  setfacl: aaa: Operation not permitted

This patch fixed it.
Signed-off-by: Shi Weihua <shiwh@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
---

diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c
index 6ef7b26724ec..6b4d0cca5c7f 100644
--- a/fs/btrfs/acl.c
+++ b/fs/btrfs/acl.c
@@ -160,6 +160,9 @@ static int btrfs_xattr_acl_set(struct dentry *dentry, const char *name,
 	int ret;
 	struct posix_acl *acl = NULL;
 
+	if (!is_owner_or_cap(dentry->d_inode))
+		return -EPERM;
+
 	if (value) {
 		acl = posix_acl_from_xattr(value, size);
 		if (acl == NULL) {