From 931dde83a2696d8794042ebbf724f60eda5983c3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ernesto=20A=2E=20Fern=C3=A1ndez?= Date: Wed, 2 Aug 2017 03:18:27 -0300 Subject: btrfs: preserve i_mode if __btrfs_set_acl() fails MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit d7d824966530acfe32b94d1ed672e6fe1638cd68 upstream. When changing a file's acl mask, btrfs_set_acl() will first set the group bits of i_mode to the value of the mask, and only then set the actual extended attribute representing the new acl. If the second part fails (due to lack of space, for example) and the file had no acl attribute to begin with, the system will from now on assume that the mask permission bits are actual group permission bits, potentially granting access to the wrong users. Prevent this by restoring the original mode bits if __btrfs_set_acl fails. Signed-off-by: Ernesto A. Fernández Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Nikolay Borisov Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/acl.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/acl.c b/fs/btrfs/acl.c index 8d8370ddb6b2..1ba49ebe67da 100644 --- a/fs/btrfs/acl.c +++ b/fs/btrfs/acl.c @@ -114,13 +114,17 @@ out: int btrfs_set_acl(struct inode *inode, struct posix_acl *acl, int type) { int ret; + umode_t old_mode = inode->i_mode; if (type == ACL_TYPE_ACCESS && acl) { ret = posix_acl_update_mode(inode, &inode->i_mode, &acl); if (ret) return ret; } - return __btrfs_set_acl(NULL, inode, acl, type); + ret = __btrfs_set_acl(NULL, inode, acl, type); + if (ret) + inode->i_mode = old_mode; + return ret; } /* -- cgit v1.2.3