Provide stubs for union/overlay copy-up handling. The xattr copy up stub discards lower SELinux xattrs rather than letting them be copied up so that the security label on the copy doesn't get corrupted.
Signed-off-by: David Howells <[email protected]> --- security/selinux/hooks.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index e4369d86e588..7c1a44d9fac3 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3190,6 +3190,24 @@ static void selinux_inode_getsecid(const struct inode *inode, u32 *secid) *secid = isec->sid; } +static int selinux_inode_copy_up(struct dentry *src, struct dentry *dst) +{ + return 0; +} + +static int selinux_inode_copy_up_xattr(struct dentry *src, struct dentry *dst, + const char *name, void *value, + size_t *size) +{ + /* The copy_up hook above sets the initial context on an inode, but we + * don't then want to overwrite it by blindly copying all the lower + * xattrs up. Instead, we have to filter out SELinux-related xattrs. + */ + if (strcmp(name, XATTR_NAME_SELINUX) == 0) + return 1; /* Discard */ + return 0; +} + /* file security operations */ static int selinux_revalidate_file_permission(struct file *file, int mask) @@ -5919,6 +5937,8 @@ static struct security_hook_list selinux_hooks[] = { LSM_HOOK_INIT(inode_setsecurity, selinux_inode_setsecurity), LSM_HOOK_INIT(inode_listsecurity, selinux_inode_listsecurity), LSM_HOOK_INIT(inode_getsecid, selinux_inode_getsecid), + LSM_HOOK_INIT(inode_copy_up, selinux_inode_copy_up), + LSM_HOOK_INIT(inode_copy_up_xattr, selinux_inode_copy_up_xattr), LSM_HOOK_INIT(file_permission, selinux_file_permission), LSM_HOOK_INIT(file_alloc_security, selinux_file_alloc_security), -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
