Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992844AbbEPIJB (ORCPT ); Sat, 16 May 2015 04:09:01 -0400 Received: from bband-dyn183.178-41-215.t-com.sk ([178.41.215.183]:22560 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2992598AbbEPIHt (ORCPT ); Sat, 16 May 2015 04:07:49 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, David Sterba , Chris Mason , Jiri Slaby Subject: [PATCH 3.12 007/142] btrfs: don't accept bare namespace as a valid xattr Date: Sat, 16 May 2015 09:36:07 +0200 Message-Id: X-Mailer: git-send-email 2.3.7 In-Reply-To: <70c3d4ae1322b9e9bd7443ef574af5635234a0fa.1431761807.git.jslaby@suse.cz> References: <70c3d4ae1322b9e9bd7443ef574af5635234a0fa.1431761807.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4591 Lines: 139 From: David Sterba 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 3c3b04d10ff1811a27f86684ccd2f5ba6983211d upstream. Due to insufficient check in btrfs_is_valid_xattr, this unexpectedly works: $ touch file $ setfattr -n user. -v 1 file $ getfattr -d file user.="1" ie. the missing attribute name after the namespace. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=94291 Reported-by: William Douglas Signed-off-by: David Sterba Signed-off-by: Chris Mason Signed-off-by: Jiri Slaby --- fs/btrfs/xattr.c | 50 +++++++++++++++++++++++++++++++++++++------------- 1 file changed, 37 insertions(+), 13 deletions(-) diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c index 05740b9789e4..7e21b2b3fcf2 100644 --- a/fs/btrfs/xattr.c +++ b/fs/btrfs/xattr.c @@ -322,21 +322,40 @@ const struct xattr_handler *btrfs_xattr_handlers[] = { /* * Check if the attribute is in a supported namespace. * - * This applied after the check for the synthetic attributes in the system + * This is applied after the check for the synthetic attributes in the system * namespace. */ -static bool btrfs_is_valid_xattr(const char *name) +static int btrfs_is_valid_xattr(const char *name) { - return !strncmp(name, XATTR_SECURITY_PREFIX, - XATTR_SECURITY_PREFIX_LEN) || - !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) || - !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) || - !strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN); + int len = strlen(name); + int prefixlen = 0; + + if (!strncmp(name, XATTR_SECURITY_PREFIX, + XATTR_SECURITY_PREFIX_LEN)) + prefixlen = XATTR_SECURITY_PREFIX_LEN; + else if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) + prefixlen = XATTR_SYSTEM_PREFIX_LEN; + else if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) + prefixlen = XATTR_TRUSTED_PREFIX_LEN; + else if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) + prefixlen = XATTR_USER_PREFIX_LEN; + else + return -EOPNOTSUPP; + + /* + * The name cannot consist of just prefix + */ + if (len <= prefixlen) + return -EINVAL; + + return 0; } ssize_t btrfs_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size) { + int ret; + /* * If this is a request for a synthetic attribute in the system.* * namespace use the generic infrastructure to resolve a handler @@ -345,8 +364,9 @@ ssize_t btrfs_getxattr(struct dentry *dentry, const char *name, if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) return generic_getxattr(dentry, name, buffer, size); - if (!btrfs_is_valid_xattr(name)) - return -EOPNOTSUPP; + ret = btrfs_is_valid_xattr(name); + if (ret) + return ret; return __btrfs_getxattr(dentry->d_inode, name, buffer, size); } @@ -354,6 +374,7 @@ int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root; + int ret; /* * The permission on security.* and system.* is not checked @@ -370,8 +391,9 @@ int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value, if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) return generic_setxattr(dentry, name, value, size, flags); - if (!btrfs_is_valid_xattr(name)) - return -EOPNOTSUPP; + ret = btrfs_is_valid_xattr(name); + if (ret) + return ret; if (size == 0) value = ""; /* empty EA, do not remove */ @@ -383,6 +405,7 @@ int btrfs_setxattr(struct dentry *dentry, const char *name, const void *value, int btrfs_removexattr(struct dentry *dentry, const char *name) { struct btrfs_root *root = BTRFS_I(dentry->d_inode)->root; + int ret; /* * The permission on security.* and system.* is not checked @@ -399,8 +422,9 @@ int btrfs_removexattr(struct dentry *dentry, const char *name) if (!strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) return generic_removexattr(dentry, name); - if (!btrfs_is_valid_xattr(name)) - return -EOPNOTSUPP; + ret = btrfs_is_valid_xattr(name); + if (ret) + return ret; return __btrfs_setxattr(NULL, dentry->d_inode, name, NULL, 0, XATTR_REPLACE); -- 2.3.7 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/