diff mbox series

[4.4,71/86] netlabel: cope with NULL catmap

Message ID 20200518173504.834119661@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg KH May 18, 2020, 5:36 p.m. UTC 
From: Paolo Abeni <pabeni@redhat.com>

[ Upstream commit eead1c2ea2509fd754c6da893a94f0e69e83ebe4 ]

The cipso and calipso code can set the MLS_CAT attribute on
successful parsing, even if the corresponding catmap has
not been allocated, as per current configuration and external
input.

Later, selinux code tries to access the catmap if the MLS_CAT flag
is present via netlbl_catmap_getlong(). That may cause null ptr
dereference while processing incoming network traffic.

Address the issue setting the MLS_CAT flag only if the catmap is
really allocated. Additionally let netlbl_catmap_getlong() cope
with NULL catmap.

Reported-by: Matthew Sheets <matthew.sheets@gd-ms.com>
Fixes: 4b8feff251da ("netlabel: fix the horribly broken catmap functions")
Fixes: ceba1832b1b2 ("calipso: Set the calipso socket label to match the secattr.")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/ipv4/cipso_ipv4.c        |    6 ++++--
 net/netlabel/netlabel_kapi.c |    6 ++++++
 2 files changed, 10 insertions(+), 2 deletions(-)
diff mbox series

Patch

--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -1343,7 +1343,8 @@  static int cipso_v4_parsetag_rbm(const s
 			return ret_val;
 		}
 
-		secattr->flags |= NETLBL_SECATTR_MLS_CAT;
+		if (secattr->attr.mls.cat)
+			secattr->flags |= NETLBL_SECATTR_MLS_CAT;
 	}
 
 	return 0;
@@ -1524,7 +1525,8 @@  static int cipso_v4_parsetag_rng(const s
 			return ret_val;
 		}
 
-		secattr->flags |= NETLBL_SECATTR_MLS_CAT;
+		if (secattr->attr.mls.cat)
+			secattr->flags |= NETLBL_SECATTR_MLS_CAT;
 	}
 
 	return 0;
--- a/net/netlabel/netlabel_kapi.c
+++ b/net/netlabel/netlabel_kapi.c
@@ -605,6 +605,12 @@  int netlbl_catmap_getlong(struct netlbl_
 	if ((off & (BITS_PER_LONG - 1)) != 0)
 		return -EINVAL;
 
+	/* a null catmap is equivalent to an empty one */
+	if (!catmap) {
+		*offset = (u32)-1;
+		return 0;
+	}
+
 	if (off < catmap->startbit) {
 		off = catmap->startbit;
 		*offset = off;