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[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>
This commit is contained in:
Konstantin Sharlaimov 2007-06-12 14:16:59 -07:00 committed by David S. Miller
parent 9cadcd28f0
commit 606f585e36
1 changed files with 5 additions and 5 deletions
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10
drivers/net/ppp_mppe.c
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@ -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. * Make sure we have enough room to decrypt the packet.
* Note that for our test we only subtract 1 byte whereas in * To account for possible PFC we should only subtract 1
* mppe_compress() we added 2 bytes (+MPPE_OVHD); * byte whereas in mppe_compress() we added 2 bytes (+MPPE_OVHD);
* this is to account for possible PFC. * 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! " printk(KERN_DEBUG "mppe_decompress[%d]: osize too small! "
"(have: %d need: %d)\n", state->unit, "(have: %d need: %d)\n", state->unit,
osize, isize - MPPE_OVHD - 1); osize, isize - MPPE_OVHD - 2);
return DECOMP_ERROR; return DECOMP_ERROR;
} }
osize = isize - MPPE_OVHD - 2; /* assume no PFC */ osize = isize - MPPE_OVHD - 2; /* assume no PFC */