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Date: Wed, 20 Jun 2007 22:37:18 +1100 From: Konstantin Sharlaimov <konstantin.sharlaimov@...il.com> To: Paul Mackerras <paulus@...ba.org> CC: Sergey Vlasov <vsu@...linux.ru>, netdev@...r.kernel.org, linux-kernel@...r.kernel.org Subject: [RFC] [PATCH 2.6.21.5] ppp: fix osize too small errors when decoding mppe The mppe_decompress() function required a buffer that is 1 byte too small when receiving a message of mru size. This fixes buffer allocation to prevent this from occurring. Signed-off-by: Konstantin Sharlaimov <konstantin.sharlaimov@...il.com> --- As Sergey Vlasov pointed out, ppp_mppe-account-for-osize-too-small-errors-in.patch may cause buffer overflows on certain data. Here is another patch that should eliminate the "osize too small" errors. Instead of patching mppe_decompress itself, I have patched ppp_decompress_frame so it would allocate the required extra byte when using mppe compression. I didn't have a chance to check this patch carefully yet, but it seem to be working as expected. Any comments would be greatly appreciated. --- linux-2.6.21.3/drivers/net/ppp_generic.c.orig 2007-06-20 09:14:13.000000000 +1100 +++ linux-2.6.21.3/drivers/net/ppp_generic.c 2007-06-20 09:18:06.000000000 +1100 @@ -1711,7 +1711,18 @@ ppp_decompress_frame(struct ppp *ppp, st goto err; if (proto == PPP_COMP) { - ns = dev_alloc_skb(ppp->mru + PPP_HDRLEN); + int obuff_size; + + switch(ppp->rcomp->compress_proto) { + case CI_MPPE: + obuff_size = ppp->mru + PPP_HDRLEN + 1; + break; + default: + obuff_size = ppp->mru + PPP_HDRLEN; + break; + } + + ns = dev_alloc_skb(obuff_size); if (ns == 0) { printk(KERN_ERR "ppp_decompress_frame: no memory\n"); goto err; - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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