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@xxxxxxxxxx> Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx> --- 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; -- To unsubscribe from this list: send the line "unsubscribe linux-unionfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
