Date: Sat, 22 Apr 2017 01:06:23 +0000 (UTC) From: =?UTF-8?Q?Dag-Erling_Sm=c3=b8rgrav?= <des@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r317277 - head/sys/crypto/chacha20 Message-ID: <201704220106.v3M16NLH097822@repo.freebsd.org>
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Author: des Date: Sat Apr 22 01:06:23 2017 New Revision: 317277 URL: https://svnweb.freebsd.org/changeset/base/317277 Log: Fix counter increment in Salsa and ChaCha. In my eagerness to eliminate a branch which is taken once per 2^38 bytes of keystream, I forgot that the state words are in host order. Thus, the counter increment code worked fine on little-endian machines, but not on big-endian ones. Switch to a simpler (branchful) solution. Modified: head/sys/crypto/chacha20/chacha20.c Modified: head/sys/crypto/chacha20/chacha20.c ============================================================================== --- head/sys/crypto/chacha20/chacha20.c Fri Apr 21 23:01:32 2017 (r317276) +++ head/sys/crypto/chacha20/chacha20.c Sat Apr 22 01:06:23 2017 (r317277) @@ -130,7 +130,6 @@ size_t chacha20_encrypt(chacha20_ctx *ctx, const void *vpt, uint8_t *ct, size_t len) { const uint8_t *pt = vpt; - uint64_t ctr; uint32_t mix[16]; uint8_t ks[64]; unsigned int b, i; @@ -157,8 +156,8 @@ chacha20_encrypt(chacha20_ctx *ctx, cons for (i = 0; i < 64 && i < len; ++i) *ct++ = *pt++ ^ ks[i]; } - ctr = le64dec(ctx->state + 12); - le64enc(ctx->state + 12, ++ctr); + if (++ctx->state[12] == 0) + ++ctx->state[13]; } return (len); }
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