netlabel: cope with NULL catmap

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: 4b8feff251 ("netlabel: fix the horribly broken catmap functions")
Fixes: ceba1832b1 ("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>
This commit is contained in:
Paolo Abeni
2020-05-12 14:43:14 +02:00
committed by David S. Miller
parent 24adbc1676
commit eead1c2ea2
3 changed files with 12 additions and 3 deletions

View File

@@ -734,6 +734,12 @@ int netlbl_catmap_getlong(struct netlbl_lsm_catmap *catmap,
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;