[PATCH] crypto: arm/chacha-neon - add missing counter increment

[Ard Biesheuvel <ardb@kernel.org>]

Commit 86cd97ec4b943af3 ("crypto: arm/chacha-neon - optimize for non-block
size multiples") refactored the chacha block handling in the glue code in
a way that may result in the counter increment to be omitted when calling
chacha_block_xor_neon() to process a full block. This violates the API,
which requires that the output IV is suitable for handling more input as
long as the preceding input has been presented in round multiples of the
block size.

So increment the counter after calling chacha_block_xor_neon().

Fixes: 86cd97ec4b943af3 ("crypto: arm/chacha-neon - optimize for non-block size multiples")
Reported-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm/crypto/chacha-glue.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/crypto/chacha-glue.c b/arch/arm/crypto/chacha-glue.c
index 7b5cf8430c6d..f19e6da8cdd0 100644
--- a/arch/arm/crypto/chacha-glue.c
+++ b/arch/arm/crypto/chacha-glue.c
@@ -60,6 +60,7 @@ static void chacha_doneon(u32 *state, u8 *dst, const u8 *src,
 		chacha_block_xor_neon(state, d, s, nrounds);
 		if (d != dst)
 			memcpy(dst, buf, bytes);
+		state[12] += 1;
 	}
 }
 
-- 
2.17.1