From 47309ea1359115125d9cab17a279c8df72b47235 Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Tue, 28 Nov 2023 14:52:57 +0800 Subject: crypto: arc4 - Add internal state The arc4 algorithm has always had internal state. It's been buggy from day one in that the state has been stored in the shared tfm object. That means two users sharing the same tfm will end up affecting each other's output, or worse, they may end up with the same output. Fix this by declaring an internal state and storing the state there instead of within the tfm context. Signed-off-by: Herbert Xu --- crypto/arc4.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'crypto') diff --git a/crypto/arc4.c b/crypto/arc4.c index 2150f94e7d03..1a4825c97c5a 100644 --- a/crypto/arc4.c +++ b/crypto/arc4.c @@ -14,6 +14,8 @@ #include #include +#define ARC4_ALIGN __alignof__(struct arc4_ctx) + static int crypto_arc4_setkey(struct crypto_lskcipher *tfm, const u8 *in_key, unsigned int key_len) { @@ -23,10 +25,15 @@ static int crypto_arc4_setkey(struct crypto_lskcipher *tfm, const u8 *in_key, } static int crypto_arc4_crypt(struct crypto_lskcipher *tfm, const u8 *src, - u8 *dst, unsigned nbytes, u8 *iv, u32 flags) + u8 *dst, unsigned nbytes, u8 *siv, u32 flags) { struct arc4_ctx *ctx = crypto_lskcipher_ctx(tfm); + if (!(flags & CRYPTO_LSKCIPHER_FLAG_CONT)) + memcpy(siv, ctx, sizeof(*ctx)); + + ctx = (struct arc4_ctx *)siv; + arc4_crypt(ctx, dst, src, nbytes); return 0; } @@ -45,9 +52,11 @@ static struct lskcipher_alg arc4_alg = { .co.base.cra_priority = 100, .co.base.cra_blocksize = ARC4_BLOCK_SIZE, .co.base.cra_ctxsize = sizeof(struct arc4_ctx), + .co.base.cra_alignmask = ARC4_ALIGN - 1, .co.base.cra_module = THIS_MODULE, .co.min_keysize = ARC4_MIN_KEY_SIZE, .co.max_keysize = ARC4_MAX_KEY_SIZE, + .co.statesize = sizeof(struct arc4_ctx), .setkey = crypto_arc4_setkey, .encrypt = crypto_arc4_crypt, .decrypt = crypto_arc4_crypt, -- cgit v1.2.3