| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <20160711134004.GA7728@redhat.com>
Date: Mon, 11 Jul 2016 09:40:04 -0400
From: Vivek Goyal <vgoyal@...hat.com>
To: kbuild test robot <lkp@...el.com>
Cc: kbuild-all@...org, miklos@...redi.hu, sds@...ho.nsa.gov,
pmoore@...hat.com, casey@...aufler-ca.com,
linux-kernel@...r.kernel.org, linux-unionfs@...r.kernel.org,
linux-security-module@...r.kernel.org, dwalsh@...hat.com,
dhowells@...hat.com, viro@...IV.linux.org.uk,
linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH 3/7] security,overlayfs: Provide security hook for copy
up of xattrs for overlay file
On Sat, Jul 09, 2016 at 01:41:38AM +0800, kbuild test robot wrote:
> Hi,
>
> [auto build test ERROR on next-20160708]
> [also build test ERROR on v4.7-rc6]
> [cannot apply to pcmoore-selinux/next security/next v4.7-rc6 v4.7-rc5 v4.7-rc4]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
These patches should be applied on top of overlayfs-next branch of
miklos's vfs tree.
git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git overlayfs-next
>
> url: https://github.com/0day-ci/linux/commits/Vivek-Goyal/Overlayfs-SELinux-Support/20160709-002635
> config: mips-gpr_defconfig (attached as .config)
> compiler: mips-linux-gnu-gcc (Debian 5.3.1-8) 5.3.1 20160205
> reproduce:
> wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # save the attached .config to linux build tree
> make.cross ARCH=mips
>
> All errors (new ones prefixed by >>):
>
> In file included from arch/mips/kernel/ptrace.c:27:0:
> include/linux/security.h: In function 'security_inode_copy_up_xattr':
> >> include/linux/security.h:770:2: error: statement with no effect [-Werror=unused-value]
> -EOPNOTSUPP;
> ^
> include/linux/security.h:771:1: error: no return statement in function returning non-void [-Werror=return-type]
> }
Typo. No "return" keyword. Fixed in attached patch.
Subject: security,overlayfs: Provide security hook for copy up of xattrs for overlay file
Provide a security hook which is called when xattrs of a file are being
copied up. This hook is called once for each xattr and LSM can return 0
to access the xattr, 1 to reject xattr, -EOPNOTSUPP if none of the lsms
claim to know xattr and a negative error code if something went terribly
wrong.
If 0 or -EOPNOTSUPP is returned, xattr will be copied up, if 1 is returned,
xattr will not be copied up and if negative error code is returned, copy up
will be aborted.
Signed-off-by: David Howells <dhowells@...hat.com>
Signed-off-by: Vivek Goyal <vgoyal@...hat.com>
---
fs/overlayfs/copy_up.c | 7 +++++++
include/linux/lsm_hooks.h | 10 ++++++++++
include/linux/security.h | 6 ++++++
security/security.c | 8 ++++++++
4 files changed, 31 insertions(+)
Index: rhvgoyal-linux/include/linux/lsm_hooks.h
===================================================================
--- rhvgoyal-linux.orig/include/linux/lsm_hooks.h 2016-07-11 09:23:09.113863783 -0400
+++ rhvgoyal-linux/include/linux/lsm_hooks.h 2016-07-11 09:23:15.541863783 -0400
@@ -410,6 +410,14 @@
* @src indicates the union dentry of file that is being copied up.
* @new pointer to pointer to return newly allocated creds.
* Returns 0 on success or a negative error code on error.
+ * @inode_copy_up_xattr:
+ * Filter the xattrs being copied up when a unioned file is copied
+ * up from a lower layer to the union/overlay layer.
+ * @name indicates the name of the xattr.
+ * Returns 0 to accept the xattr, 1 to discard the xattr, -EOPNOTSUPP if
+ * security module does not know about attribute or a negative error code
+ * to abort the copy up. Note that the caller is responsible for reading
+ * and writing the xattrs as this hook is merely a filter.
*
* Security hooks for file operations
*
@@ -1435,6 +1443,7 @@ union security_list_options {
size_t buffer_size);
void (*inode_getsecid)(struct inode *inode, u32 *secid);
int (*inode_copy_up) (struct dentry *src, struct cred **new);
+ int (*inode_copy_up_xattr) (const char *name);
int (*file_permission)(struct file *file, int mask);
int (*file_alloc_security)(struct file *file);
@@ -1707,6 +1716,7 @@ struct security_hook_heads {
struct list_head inode_listsecurity;
struct list_head inode_getsecid;
struct list_head inode_copy_up;
+ struct list_head inode_copy_up_xattr;
struct list_head file_permission;
struct list_head file_alloc_security;
struct list_head file_free_security;
Index: rhvgoyal-linux/include/linux/security.h
===================================================================
--- rhvgoyal-linux.orig/include/linux/security.h 2016-07-11 09:23:09.117863783 -0400
+++ rhvgoyal-linux/include/linux/security.h 2016-07-11 09:23:48.528863783 -0400
@@ -283,6 +283,7 @@ int security_inode_setsecurity(struct in
int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size);
void security_inode_getsecid(struct inode *inode, u32 *secid);
int security_inode_copy_up(struct dentry *src, struct cred **new);
+int security_inode_copy_up_xattr(const char *name);
int security_file_permission(struct file *file, int mask);
int security_file_alloc(struct file *file);
void security_file_free(struct file *file);
@@ -764,6 +765,11 @@ static inline int security_inode_copy_up
return 0;
}
+static inline int security_inode_copy_up_xattr(const char *name)
+{
+ return -EOPNOTSUPP;
+}
+
static inline int security_file_permission(struct file *file, int mask)
{
return 0;
Index: rhvgoyal-linux/security/security.c
===================================================================
--- rhvgoyal-linux.orig/security/security.c 2016-07-11 09:23:09.119863783 -0400
+++ rhvgoyal-linux/security/security.c 2016-07-11 09:23:15.544863783 -0400
@@ -733,6 +733,12 @@ int security_inode_copy_up(struct dentry
}
EXPORT_SYMBOL(security_inode_copy_up);
+int security_inode_copy_up_xattr(const char *name)
+{
+ return call_int_hook(inode_copy_up_xattr, -EOPNOTSUPP, name);
+}
+EXPORT_SYMBOL(security_inode_copy_up_xattr);
+
int security_file_permission(struct file *file, int mask)
{
int ret;
@@ -1671,6 +1677,8 @@ struct security_hook_heads security_hook
LIST_HEAD_INIT(security_hook_heads.inode_getsecid),
.inode_copy_up =
LIST_HEAD_INIT(security_hook_heads.inode_copy_up),
+ .inode_copy_up_xattr =
+ LIST_HEAD_INIT(security_hook_heads.inode_copy_up_xattr),
.file_permission =
LIST_HEAD_INIT(security_hook_heads.file_permission),
.file_alloc_security =
Index: rhvgoyal-linux/fs/overlayfs/copy_up.c
===================================================================
--- rhvgoyal-linux.orig/fs/overlayfs/copy_up.c 2016-07-11 09:23:09.120863783 -0400
+++ rhvgoyal-linux/fs/overlayfs/copy_up.c 2016-07-11 09:23:15.544863783 -0400
@@ -103,6 +103,13 @@ retry:
goto retry;
}
+ error = security_inode_copy_up_xattr(name);
+ if (error < 0 && error != -EOPNOTSUPP)
+ break;
+ if (error == 1) {
+ error = 0;
+ continue; /* Discard */
+ }
error = vfs_setxattr(new, name, value, size, 0);
if (error)
break;
Powered by blists - more mailing lists