x25: add a sanity check parsing X.25 facilities
This was found with a manual audit and I don't have a reproducer. We
limit ->calling_len and ->called_len when we get them from
copy_from_user() in x25_ioctl() so when they come from skb->data then
we should cap them there as well.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/x25/x25_facilities.c b/net/x25/x25_facilities.c
index 66c63873..b825325 100644
--- a/net/x25/x25_facilities.c
+++ b/net/x25/x25_facilities.c
@@ -156,6 +156,8 @@
case X25_FAC_CALLING_AE:
if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1)
return -1;
+ if (p[2] > X25_MAX_AE_LEN)
+ return -1;
dte_facs->calling_len = p[2];
memcpy(dte_facs->calling_ae, &p[3], p[1] - 1);
*vc_fac_mask |= X25_MASK_CALLING_AE;
@@ -163,6 +165,8 @@
case X25_FAC_CALLED_AE:
if (p[1] > X25_MAX_DTE_FACIL_LEN || p[1] <= 1)
return -1;
+ if (p[2] > X25_MAX_AE_LEN)
+ return -1;
dte_facs->called_len = p[2];
memcpy(dte_facs->called_ae, &p[3], p[1] - 1);
*vc_fac_mask |= X25_MASK_CALLED_AE;