[PPP]: Revert 606f585e363527da9feaed79465132c0c661fd9e

This can cause packet buffer overflows in certain cases,
the real bug will be fixed differently in a followon
changeset.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 5 deletions

diff --git a/drivers/net/ppp_mppe.c b/drivers/net/ppp_mppe.c
index 5ae80bbe2edc..d5bdd2574659 100644
--- a/drivers/net/ppp_mppe.c
+++ b/drivers/net/ppp_mppe.c
@@ -493,14 +493,14 @@ mppe_decompress(void *arg, unsigned char *ibuf, int isize, unsigned char *obuf,
 
         /*
          * Make sure we have enough room to decrypt the packet.
-         * 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.
+         * 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.
          */
-        if (osize < isize - MPPE_OVHD - 2) {
+        if (osize < isize - MPPE_OVHD - 1) {
                 printk(KERN_DEBUG "mppe_decompress[%d]: osize too small! "
                        "(have: %d need: %d)\n", state->unit,
-                       osize, isize - MPPE_OVHD - 2);
+                       osize, isize - MPPE_OVHD - 1);
                 return DECOMP_ERROR;
         }
         osize = isize - MPPE_OVHD - 2;  /* assume no PFC */