[PATCH AUTOSEL 6.6 205/294] smack: recognize ipv4 CIPSO w/o categories

[PATCH AUTOSEL 6.6 205/294] smack: recognize ipv4 CIPSO w/o categories

[Sasha Levin]

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 5dd1e164f9b13..d27e8b916bfb9 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -933,6 +933,10 @@ 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);
-- 
2.39.5

[PATCH AUTOSEL 6.6 206/294] smack: Revert "smackfs: Added check catlen"

[Sasha Levin]

From: Konstantin Andreev <andreev@swemel.ru>

[ Upstream commit c7fb50cecff9cad19fdac5b37337eae4e42b94c7 ]

This reverts commit ccfd889acb06eab10b98deb4b5eef0ec74157ea0

The indicated commit
* does not describe the problem that change tries to solve
* has programming issues
* introduces a bug: forever clears NETLBL_SECATTR_MLS_CAT
         in (struct smack_known *)skp->smk_netlabel.flags

Reverting the commit to reapproach original problem

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 | 17 +++--------------
 1 file changed, 3 insertions(+), 14 deletions(-)

diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
index d27e8b916bfb9..1e35c9f807b2b 100644
--- a/security/smack/smackfs.c
+++ b/security/smack/smackfs.c
@@ -830,7 +830,7 @@ static int smk_open_cipso(struct inode *inode, struct file *file)
 static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
 				size_t count, loff_t *ppos, int format)
 {
-	struct netlbl_lsm_catmap *old_cat, *new_cat = NULL;
+	struct netlbl_lsm_catmap *old_cat;
 	struct smack_known *skp;
 	struct netlbl_lsm_secattr ncats;
 	char mapcatset[SMK_CIPSOLEN];
@@ -917,19 +917,8 @@ static ssize_t smk_set_cipso(struct file *file, const char __user *buf,
 
 		smack_catset_bit(cat, mapcatset);
 	}
-	ncats.flags = 0;
-	if (catlen == 0) {
-		ncats.attr.mls.cat = NULL;
-		ncats.attr.mls.lvl = maplevel;
-		new_cat = netlbl_catmap_alloc(GFP_ATOMIC);
-		if (new_cat)
-			new_cat->next = ncats.attr.mls.cat;
-		ncats.attr.mls.cat = new_cat;
-		skp->smk_netlabel.flags &= ~(1U << 3);
-		rc = 0;
-	} else {
-		rc = smk_netlbl_mls(maplevel, mapcatset, &ncats, SMK_CIPSOLEN);
-	}
+
+	rc = smk_netlbl_mls(maplevel, mapcatset, &ncats, SMK_CIPSOLEN);
 	if (rc >= 0) {
 		old_cat = skp->smk_netlabel.attr.mls.cat;
 		rcu_assign_pointer(skp->smk_netlabel.attr.mls.cat, ncats.attr.mls.cat);
-- 
2.39.5