summaryrefslogtreecommitdiffstats
path: root/crypto/testmgr.h
diff options
context:
space:
mode:
authorEric Biggers <ebiggers@google.com>2019-03-31 13:04:11 -0700
committerHerbert Xu <herbert@gondor.apana.org.au>2019-04-08 14:43:06 +0800
commit678cce4019d746da6c680c48ba9e6d417803e127 (patch)
treef1fb27e128d51a60ceb4d961dd7baf11fa1525fa /crypto/testmgr.h
parentb4e9e931e9bb2f5b302ce66640832f5a3e57e8c4 (diff)
crypto: x86/poly1305 - fix overflow during partial reduction
The x86_64 implementation of Poly1305 produces the wrong result on some inputs because poly1305_4block_avx2() incorrectly assumes that when partially reducing the accumulator, the bits carried from limb 'd4' to limb 'h0' fit in a 32-bit integer. This is true for poly1305-generic which processes only one block at a time. However, it's not true for the AVX2 implementation, which processes 4 blocks at a time and therefore can produce intermediate limbs about 4x larger. Fix it by making the relevant calculations use 64-bit arithmetic rather than 32-bit. Note that most of the carries already used 64-bit arithmetic, but the d4 -> h0 carry was different for some reason. To be safe I also made the same change to the corresponding SSE2 code, though that only operates on 1 or 2 blocks at a time. I don't think it's really needed for poly1305_block_sse2(), but it doesn't hurt because it's already x86_64 code. It *might* be needed for poly1305_2block_sse2(), but overflows aren't easy to reproduce there. This bug was originally detected by my patches that improve testmgr to fuzz algorithms against their generic implementation. But also add a test vector which reproduces it directly (in the AVX2 case). Fixes: b1ccc8f4b631 ("crypto: poly1305 - Add a four block AVX2 variant for x86_64") Fixes: c70f4abef07a ("crypto: poly1305 - Add a SSE2 SIMD variant for x86_64") Cc: <stable@vger.kernel.org> # v4.3+ Cc: Martin Willi <martin@strongswan.org> Cc: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Martin Willi <martin@strongswan.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/testmgr.h')
-rw-r--r--crypto/testmgr.h44
1 files changed, 43 insertions, 1 deletions
diff --git a/crypto/testmgr.h b/crypto/testmgr.h
index f267633cf13a..d18a37629f05 100644
--- a/crypto/testmgr.h
+++ b/crypto/testmgr.h
@@ -5634,7 +5634,49 @@ static const struct hash_testvec poly1305_tv_template[] = {
.psize = 80,
.digest = "\x13\x00\x00\x00\x00\x00\x00\x00"
"\x00\x00\x00\x00\x00\x00\x00\x00",
- },
+ }, { /* Regression test for overflow in AVX2 implementation */
+ .plaintext = "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff\xff\xff\xff\xff"
+ "\xff\xff\xff\xff",
+ .psize = 300,
+ .digest = "\xfb\x5e\x96\xd8\x61\xd5\xc7\xc8"
+ "\x78\xe5\x87\xcc\x2d\x5a\x22\xe1",
+ }
};
/* NHPoly1305 test vectors from https://github.com/google/adiantum */