From a158a937d864d0034fea14913c1f09c6d5f574b8 Mon Sep 17 00:00:00 2001 From: Konstantin Andreev Date: Fri, 17 Jan 2025 02:40:34 +0300 Subject: [PATCH] smack: recognize ipv4 CIPSO w/o categories If SMACK label has CIPSO representation w/o categories, e.g.: | # cat /smack/cipso2 | foo 10 | @ 250/2 | ... then SMACK does not recognize such CIPSO in input ipv4 packets and substitues '*' label instead. Audit records may look like | lsm=SMACK fn=smack_socket_sock_rcv_skb action=denied | subject="*" object="_" requested=w pid=0 comm="swapper/1" ... This happens in two steps: 1) security/smack/smackfs.c`smk_set_cipso does not clear NETLBL_SECATTR_MLS_CAT from (struct smack_known *)skp->smk_netlabel.flags on assigning CIPSO w/o categories: | rcu_assign_pointer(skp->smk_netlabel.attr.mls.cat, ncats.attr.mls.cat); | skp->smk_netlabel.attr.mls.lvl = ncats.attr.mls.lvl; 2) security/smack/smack_lsm.c`smack_from_secattr can not match skp->smk_netlabel with input packet's struct netlbl_lsm_secattr *sap because sap->flags have not NETLBL_SECATTR_MLS_CAT (what is correct) but skp->smk_netlabel.flags have (what is incorrect): | if ((sap->flags & NETLBL_SECATTR_MLS_CAT) == 0) { | if ((skp->smk_netlabel.flags & | NETLBL_SECATTR_MLS_CAT) == 0) | found = 1; | break; | } This commit sets/clears NETLBL_SECATTR_MLS_CAT in skp->smk_netlabel.flags according to the presense of CIPSO categories. The update of smk_netlabel is not atomic, so input packets processing still may be incorrect during short time while update proceeds. Signed-off-by: Konstantin Andreev Signed-off-by: Casey Schaufler --- security/smack/smackfs.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index 2802c480521ca..90a67e410808f 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -906,6 +906,10 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf, if (rc >= 0) { old_cat = skp->smk_netlabel.attr.mls.cat; rcu_assign_pointer(skp->smk_netlabel.attr.mls.cat, ncats.attr.mls.cat); + if (ncats.attr.mls.cat) + skp->smk_netlabel.flags |= NETLBL_SECATTR_MLS_CAT; + else + skp->smk_netlabel.flags &= ~(u32)NETLBL_SECATTR_MLS_CAT; skp->smk_netlabel.attr.mls.lvl = ncats.attr.mls.lvl; synchronize_rcu(); netlbl_catmap_free(old_cat);