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From: Andreas Steinmetz <ast@domdv.de>
To: Linux Kernel Mailinglist <linux-kernel@vger.kernel.org>,
	jmorris@intercode.com.au, herbert@gondor.apana.org.au
Subject: 2.6.13rc3: crypto horribly broken on all 64bit archs
Date: Sun, 17 Jul 2005 14:20:21 +0200	[thread overview]
Message-ID: <42DA4D05.7000403@domdv.de> (raw)

[-- Attachment #1: Type: text/plain, Size: 669 bytes --]

from include/linux/kernel.h:

#define ALIGN(x,a) (((x)+(a)-1)&~((a)-1))

from crypto/cipher.c:

unsigned int alignmask = ...
u8 *src = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
...
unsigned int alignmask = ...
u8 *tmp = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
...
unsigned int align;
addr = ALIGN(addr, align);
addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);

The compiler first does ~((a)-1)) and then expands the unsigned int to
unsigned long for the & operation. So we end up with only the lower 32
bits of the address. Who did smoke what to do this? Patch attached.
-- 
Andreas Steinmetz                       SPAMmers use robotrap@domdv.de


[-- Attachment #2: crypto.patch --]
[-- Type: text/plain, Size: 980 bytes --]

--- linux.orig/crypto/cipher.c	2005-07-17 13:35:15.000000000 +0200
+++ linux/crypto/cipher.c	2005-07-17 14:04:00.000000000 +0200
@@ -41,7 +41,7 @@
 			       struct scatter_walk *in,
 			       struct scatter_walk *out, unsigned int bsize)
 {
-	unsigned int alignmask = crypto_tfm_alg_alignmask(desc->tfm);
+	unsigned long alignmask = crypto_tfm_alg_alignmask(desc->tfm);
 	u8 buffer[bsize * 2 + alignmask];
 	u8 *src = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
 	u8 *dst = src + bsize;
@@ -160,7 +160,7 @@
 			      unsigned int nbytes)
 {
 	struct crypto_tfm *tfm = desc->tfm;
-	unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
+	unsigned long alignmask = crypto_tfm_alg_alignmask(tfm);
 	u8 *iv = desc->info;
 
 	if (unlikely(((unsigned long)iv & alignmask))) {
@@ -424,7 +424,7 @@
 	}
 	
 	if (ops->cit_mode == CRYPTO_TFM_MODE_CBC) {
-		unsigned int align;
+		unsigned long align;
 		unsigned long addr;
 	    	
 	    	switch (crypto_tfm_alg_blocksize(tfm)) {

             reply	other threads:[~2005-07-17 12:20 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-07-17 12:20 Andreas Steinmetz [this message]
2005-07-17 20:45 ` 2.6.13rc3: crypto horribly broken on all 64bit archs Herbert Xu
2005-07-18 20:24   ` David S. Miller
2005-07-20  4:41 ` Andy Isaacson

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