[PATCH] libgcrypt-1.5: rinjdael: Fix use of SSE2 outside USE_AESNI/ctx->use_aesni

[Jussi Kivilinna]

* cipher/rijndael.c (_gcry_aes_cbc_enc, _gcry_aes_cbc_dec): Check if
AES-NI is enabled before calling aesni_prepare() and aesni_cleanup().
--

aesni_cleanup() contains SSE2 instructions that are interpreted as MMX on CPUs
without SSE2 support (Pentium-III, etc). In above functions, aesni_cleanup()
was called outside use_aesni checks. This causes x87 register state to be
poisoned, causing crashes later on when program tries to use floating point
registers.

Add missing '#ifdef USE_AESNI' and 'if (ctx->use_aesni)' for aesni_cleanup()
and, while at it, for aesni_prepare() too.

Reported-by: Mitsutoshi NAKANO <bkbin005 at rinku.zaq.ne.jp>
Signed-off-by: Jussi Kivilinna <jussi.kivilinna at mbnet.fi>
---
 cipher/rijndael.c |   24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/cipher/rijndael.c b/cipher/rijndael.c
index 92fa31d..9816280 100644
--- a/cipher/rijndael.c
+++ b/cipher/rijndael.c
@@ -1239,7 +1239,11 @@ _gcry_aes_cbc_enc (void *context, unsigned char *iv,
   unsigned char *ivp;
   int i;
 
-  aesni_prepare ();
+#ifdef USE_AESNI
+  if (ctx->use_aesni)
+    aesni_prepare ();
+#endif /*USE_AESNI*/
+
   for ( ;nblocks; nblocks-- )
     {
       for (ivp=iv, i=0; i < BLOCKSIZE; i++ )
@@ -1263,7 +1267,11 @@ _gcry_aes_cbc_enc (void *context, unsigned char *iv,
       if (!cbc_mac)
         outbuf += BLOCKSIZE;
     }
-  aesni_cleanup ();
+
+#ifdef USE_AESNI
+  if (ctx->use_aesni)
+    aesni_cleanup ();
+#endif /*USE_AESNI*/
 
   _gcry_burn_stack (48 + 2*sizeof(int));
 }
@@ -1575,7 +1583,11 @@ _gcry_aes_cbc_dec (void *context, unsigned char *iv,
   int i;
   unsigned char savebuf[BLOCKSIZE];
 
-  aesni_prepare ();
+#ifdef USE_AESNI
+  if (ctx->use_aesni)
+    aesni_prepare ();
+#endif /*USE_AESNI*/
+
   for ( ;nblocks; nblocks-- )
     {
       /* We need to save INBUF away because it may be identical to
@@ -1601,7 +1613,11 @@ _gcry_aes_cbc_dec (void *context, unsigned char *iv,
       inbuf += BLOCKSIZE;
       outbuf += BLOCKSIZE;
     }
-  aesni_cleanup ();
+
+#ifdef USE_AESNI
+  if (ctx->use_aesni)
+    aesni_cleanup ();
+#endif /*USE_AESNI*/
 
   _gcry_burn_stack (48 + 2*sizeof(int) + BLOCKSIZE + 4*sizeof (char*));
 }