5.4-stable review patch. If anyone has any objections, please let me know.
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From: Konstantin Andreev andreev@swemel.ru
[ Upstream commit a158a937d864d0034fea14913c1f09c6d5f574b8 ]
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 andreev@swemel.ru Signed-off-by: Casey Schaufler casey@schaufler-ca.com Signed-off-by: Sasha Levin sashal@kernel.org --- security/smack/smackfs.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c index ddb0a292802ef..526598b40b13c 100644 --- a/security/smack/smackfs.c +++ b/security/smack/smackfs.c @@ -921,6 +921,10 @@ 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);