[PPP_MPPE]: Fix "osize too small" check.
Prevent mppe_decompress() from generating "osize too small" errors when
checking for output buffer size. When receiving a packet of mru size the
output buffer for decrypted data is 1 byte too small since
mppe_decompress() tries to account for possible PFC, however later in code
it is assumed no PFC.
Adjusting the check prevented these errors from occurring.
Signed-off-by: Konstantin Sharlaimov <konstantin.sharlaimov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ppp_mppe.c b/drivers/net/ppp_mppe.c
index d5bdd25..5ae80bb 100644
--- a/drivers/net/ppp_mppe.c
+++ b/drivers/net/ppp_mppe.c
@@ -493,14 +493,14 @@
/*
* Make sure we have enough room to decrypt the packet.
- * Note that for our test we only subtract 1 byte whereas in
- * mppe_compress() we added 2 bytes (+MPPE_OVHD);
- * this is to account for possible PFC.
+ * To account for possible PFC we should only subtract 1
+ * byte whereas in mppe_compress() we added 2 bytes (+MPPE_OVHD);
+ * However, we assume no PFC, thus subtracting 2 bytes.
*/
- if (osize < isize - MPPE_OVHD - 1) {
+ if (osize < isize - MPPE_OVHD - 2) {
printk(KERN_DEBUG "mppe_decompress[%d]: osize too small! "
"(have: %d need: %d)\n", state->unit,
- osize, isize - MPPE_OVHD - 1);
+ osize, isize - MPPE_OVHD - 2);
return DECOMP_ERROR;
}
osize = isize - MPPE_OVHD - 2; /* assume no PFC */