From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Stephen Smalley , Paul Moore , Sasha Levin Subject: [PATCH 4.4 064/190] selinux: do not check open permission on sockets Date: Wed, 11 Apr 2018 20:35:10 +0200 Message-Id: <20180411183554.036420469@linuxfoundation.org> In-Reply-To: <20180411183550.114495991@linuxfoundation.org> References: <20180411183550.114495991@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stephen Smalley [ Upstream commit ccb544781d34afdb73a9a73ae53035d824d193bf ] open permission is currently only defined for files in the kernel (COMMON_FILE_PERMS rather than COMMON_FILE_SOCK_PERMS). Construction of an artificial test case that tries to open a socket via /proc/pid/fd will generate a recvfrom avc denial because recvfrom and open happen to map to the same permission bit in socket vs file classes. open of a socket via /proc/pid/fd is not supported by the kernel regardless and will ultimately return ENXIO. But we hit the permission check first and can thus produce these odd/misleading denials. Omit the open check when operating on a socket. Signed-off-by: Stephen Smalley Signed-off-by: Paul Moore Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- security/selinux/hooks.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -1942,8 +1942,9 @@ static inline u32 file_to_av(struct file static inline u32 open_file_to_av(struct file *file) { u32 av = file_to_av(file); + struct inode *inode = file_inode(file); - if (selinux_policycap_openperm) + if (selinux_policycap_openperm && inode->i_sb->s_magic != SOCKFS_MAGIC) av |= FILE__OPEN; return av; @@ -2912,6 +2913,7 @@ static int selinux_inode_permission(stru static int selinux_inode_setattr(struct dentry *dentry, struct iattr *iattr) { const struct cred *cred = current_cred(); + struct inode *inode = d_backing_inode(dentry); unsigned int ia_valid = iattr->ia_valid; __u32 av = FILE__WRITE; @@ -2927,8 +2929,10 @@ static int selinux_inode_setattr(struct ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_TIMES_SET)) return dentry_has_perm(cred, dentry, FILE__SETATTR); - if (selinux_policycap_openperm && (ia_valid & ATTR_SIZE) - && !(ia_valid & ATTR_FILE)) + if (selinux_policycap_openperm && + inode->i_sb->s_magic != SOCKFS_MAGIC && + (ia_valid & ATTR_SIZE) && + !(ia_valid & ATTR_FILE)) av |= FILE__OPEN; return dentry_has_perm(cred, dentry, av);