netlabel: fix out-of-bounds memory accesses

[ Upstream commit 5578de4834fe0f2a34fedc7374be691443396d1f ]

There are two array out-of-bounds memory accesses, one in
cipso_v4_map_lvl_valid(), the other in netlbl_bitmap_walk().  Both
errors are embarassingly simple, and the fixes are straightforward.

As a FYI for anyone backporting this patch to kernels prior to v4.8,
you'll want to apply the netlbl_bitmap_walk() patch to
cipso_v4_bitmap_walk() as netlbl_bitmap_walk() doesn't exist before
Linux v4.8.

Reported-by: Jann Horn <jannh@google.com>
Fixes: 446fda4f2682 ("[NetLabel]: CIPSOv4 engine")
Fixes: 3faa8f982f95 ("netlabel: Move bitmap manipulation functions to the NetLabel core.")
Signed-off-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>

diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index eeed8b3..7fe6430 100644 (file)
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -167,7 +167,8 @@ static int cipso_v4_bitmap_walk(const unsigned char *bitmap,
                    (state == 0 && (byte & bitmask) == 0))
                        return bit_spot;
 
-               bit_spot++;
+               if (++bit_spot >= bitmap_len)
+                       return -1;
                bitmask >>= 1;
                if (bitmask == 0) {
                        byte = bitmap[++byte_offset];
@@ -737,7 +738,8 @@ static int cipso_v4_map_lvl_valid(const struct cipso_v4_doi *doi_def, u8 level)
        case CIPSO_V4_MAP_PASS:
                return 0;
        case CIPSO_V4_MAP_TRANS:
-               if (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL)
+               if ((level < doi_def->map.std->lvl.cipso_size) &&
+                   (doi_def->map.std->lvl.cipso[level] < CIPSO_V4_INV_LVL))
                        return 0;
                break;
        }