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author | Jason A. Donenfeld <Jason@zx2c4.com> | 2020-01-05 22:40:49 -0500 |
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committer | Herbert Xu <herbert@gondor.apana.org.au> | 2020-01-16 15:18:12 +0800 |
commit | 31899908a0d248b030b4464425b86c717e0007d4 (patch) | |
tree | 6b03c839d853a5e1d9971405d53c532e768d02b7 /arch/arm/crypto | |
parent | d7d7b853566254648df59f7ea27ea05952a6cfa8 (diff) | |
download | linux-stable-31899908a0d248b030b4464425b86c717e0007d4.tar.gz linux-stable-31899908a0d248b030b4464425b86c717e0007d4.tar.bz2 linux-stable-31899908a0d248b030b4464425b86c717e0007d4.zip |
crypto: {arm,arm64,mips}/poly1305 - remove redundant non-reduction from emit
This appears to be some kind of copy and paste error, and is actually
dead code.
Pre: f = 0 ⇒ (f >> 32) = 0
f = (f >> 32) + le32_to_cpu(digest[0]);
Post: 0 ≤ f < 2³²
put_unaligned_le32(f, dst);
Pre: 0 ≤ f < 2³² ⇒ (f >> 32) = 0
f = (f >> 32) + le32_to_cpu(digest[1]);
Post: 0 ≤ f < 2³²
put_unaligned_le32(f, dst + 4);
Pre: 0 ≤ f < 2³² ⇒ (f >> 32) = 0
f = (f >> 32) + le32_to_cpu(digest[2]);
Post: 0 ≤ f < 2³²
put_unaligned_le32(f, dst + 8);
Pre: 0 ≤ f < 2³² ⇒ (f >> 32) = 0
f = (f >> 32) + le32_to_cpu(digest[3]);
Post: 0 ≤ f < 2³²
put_unaligned_le32(f, dst + 12);
Therefore this sequence is redundant. And Andy's code appears to handle
misalignment acceptably.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Tested-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'arch/arm/crypto')
-rw-r--r-- | arch/arm/crypto/poly1305-glue.c | 18 |
1 files changed, 2 insertions, 16 deletions
diff --git a/arch/arm/crypto/poly1305-glue.c b/arch/arm/crypto/poly1305-glue.c index abe3f2d587dc..ceec04ec2f40 100644 --- a/arch/arm/crypto/poly1305-glue.c +++ b/arch/arm/crypto/poly1305-glue.c @@ -20,7 +20,7 @@ void poly1305_init_arm(void *state, const u8 *key); void poly1305_blocks_arm(void *state, const u8 *src, u32 len, u32 hibit); -void poly1305_emit_arm(void *state, __le32 *digest, const u32 *nonce); +void poly1305_emit_arm(void *state, u8 *digest, const u32 *nonce); void __weak poly1305_blocks_neon(void *state, const u8 *src, u32 len, u32 hibit) { @@ -179,9 +179,6 @@ EXPORT_SYMBOL(poly1305_update_arch); void poly1305_final_arch(struct poly1305_desc_ctx *dctx, u8 *dst) { - __le32 digest[4]; - u64 f = 0; - if (unlikely(dctx->buflen)) { dctx->buf[dctx->buflen++] = 1; memset(dctx->buf + dctx->buflen, 0, @@ -189,18 +186,7 @@ void poly1305_final_arch(struct poly1305_desc_ctx *dctx, u8 *dst) poly1305_blocks_arm(&dctx->h, dctx->buf, POLY1305_BLOCK_SIZE, 0); } - poly1305_emit_arm(&dctx->h, digest, dctx->s); - - /* mac = (h + s) % (2^128) */ - f = (f >> 32) + le32_to_cpu(digest[0]); - put_unaligned_le32(f, dst); - f = (f >> 32) + le32_to_cpu(digest[1]); - put_unaligned_le32(f, dst + 4); - f = (f >> 32) + le32_to_cpu(digest[2]); - put_unaligned_le32(f, dst + 8); - f = (f >> 32) + le32_to_cpu(digest[3]); - put_unaligned_le32(f, dst + 12); - + poly1305_emit_arm(&dctx->h, dst, dctx->s); *dctx = (struct poly1305_desc_ctx){}; } EXPORT_SYMBOL(poly1305_final_arch); |