[PPP_MPPE]: Fix "osize too small" check. (606f585e) · Commits · 戴 / test

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>

drivers/net/ppp_mppe.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -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.
		* 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 */

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