From 7c51bb00c40e5608fb2cdac5230f51aeb56a28df Mon Sep 17 00:00:00 2001 From: Dmitry Kasatkin Date: Thu, 20 Nov 2014 16:31:01 +0200 Subject: evm: fix potential race when removing xattrs EVM needs to be atomically updated when removing xattrs. Otherwise concurrent EVM verification may fail in between. This patch fixes by moving i_mutex unlocking after calling EVM hook. fsnotify_xattr() is also now called while locked the same way as it is done in __vfs_setxattr_noperm. Changelog: - remove unused 'inode' variable. Signed-off-by: Dmitry Kasatkin Signed-off-by: Mimi Zohar --- security/integrity/evm/evm_main.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'security/integrity') diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c index 582091498819..1334e02ae8f4 100644 --- a/security/integrity/evm/evm_main.c +++ b/security/integrity/evm/evm_main.c @@ -387,17 +387,16 @@ void evm_inode_post_setxattr(struct dentry *dentry, const char *xattr_name, * @xattr_name: pointer to the affected extended attribute name * * Update the HMAC stored in 'security.evm' to reflect removal of the xattr. + * + * No need to take the i_mutex lock here, as this function is called from + * vfs_removexattr() which takes the i_mutex. */ void evm_inode_post_removexattr(struct dentry *dentry, const char *xattr_name) { - struct inode *inode = d_backing_inode(dentry); - if (!evm_initialized || !evm_protected_xattr(xattr_name)) return; - mutex_lock(&inode->i_mutex); evm_update_evmxattr(dentry, xattr_name, NULL, 0); - mutex_unlock(&inode->i_mutex); } /** -- cgit v1.2.3-59-g8ed1b