From patchwork Sat Dec 2 03:50:31 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Herbert Xu X-Patchwork-Id: 749895 Received: from abb.hmeau.com (abb.hmeau.com [144.6.53.87]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5483B1B3 for ; Fri, 1 Dec 2023 19:50:26 -0800 (PST) Received: from loth.rohan.me.apana.org.au ([192.168.167.2]) by formenos.hmeau.com with smtp (Exim 4.94.2 #2 (Debian)) id 1r9H1J-006120-UA; Sat, 02 Dec 2023 11:50:22 +0800 Received: by loth.rohan.me.apana.org.au (sSMTP sendmail emulation); Sat, 02 Dec 2023 11:50:31 +0800 From: "Herbert Xu" Date: Sat, 02 Dec 2023 11:50:31 +0800 Subject: [v3 PATCH 3/4] crypto: arc4 - Add internal state References: To: Eric Biggers , Linux Crypto Mailing List , Ard Biesheuvel , Vadim Fedorenko Message-Id: Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/crypto/arc4.c b/crypto/arc4.c index 2150f94e7d03..e285bfcef667 100644 --- a/crypto/arc4.c +++ b/crypto/arc4.c @@ -23,10 +23,15 @@ 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; } @@ -48,6 +53,7 @@ static struct lskcipher_alg arc4_alg = { .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,