Avoid use of untrusted security labels when s_user_ns != init_user_ns: - smk_fetch: refuse to read labels from disk - smack_inode_init_security: return -ENOTSUPP - smack_d_instantiate: don't use security xattrs from disk Signed-off-by: Seth Forshee <seth.forshee@xxxxxxxxxxxxx> --- security/smack/smack_lsm.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c index a143328f75eb..6a849da94f47 100644 --- a/security/smack/smack_lsm.c +++ b/security/smack/smack_lsm.c @@ -255,6 +255,9 @@ static struct smack_known *smk_fetch(const char *name, struct inode *ip, char *buffer; struct smack_known *skp = NULL; + if (ip->i_sb->s_user_ns != &init_user_ns) + return NULL; + if (ip->i_op->getxattr == NULL) return ERR_PTR(-EOPNOTSUPP); @@ -833,6 +836,9 @@ static int smack_inode_init_security(struct inode *inode, struct inode *dir, struct smack_known *dsp = smk_of_inode(dir); int may; + if (inode->i_sb->s_user_ns != &init_user_ns) + return -ENOTSUPP; + if (name) *name = XATTR_SMACK_SUFFIX; @@ -3176,11 +3182,13 @@ static void smack_d_instantiate(struct dentry *opt_dentry, struct inode *inode) } /* * No xattr support means, alas, no SMACK label. - * Use the aforeapplied default. + * Use the aforeapplied default. Also don't use + * xattrs from userns mounts. * It would be curious if the label of the task * does not match that assigned. */ - if (inode->i_op->getxattr == NULL) + if (inode->i_sb->s_user_ns != &init_user_ns || + inode->i_op->getxattr == NULL) break; /* * Get the dentry for xattr. -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
