[PATCH 4.20 37/76] netlabel: fix out-of-bounds memory accesses

Greg Kroah-Hartman
2019-03-08T12:57:27Z

From: Paul Moore <paul@paul-moore.com>

[ 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>
---
net/ipv4/cipso_ipv4.c | 3 ++-
net/netlabel/netlabel_kapi.c | 3 ++-
2 files changed, 4 insertions(+), 2 deletions(-)

--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -667,7 +667,8 @@ static int cipso_v4_map_lvl_valid(const
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;
}
--- a/net/netlabel/netlabel_kapi.c
+++ b/net/netlabel/netlabel_kapi.c
@@ -903,7 +903,8 @@ int netlbl_bitmap_walk(const unsigned ch
(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];