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![Herbert Xu](/assets/img/avatar_default.png)
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 <herbert@gondor.apana.org.au>
83 lines
2 KiB
C
83 lines
2 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Cryptographic API
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*
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* ARC4 Cipher Algorithm
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*
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* Jon Oberheide <jon@oberheide.org>
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*/
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#include <crypto/arc4.h>
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#include <crypto/internal/skcipher.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/sched.h>
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#define ARC4_ALIGN __alignof__(struct arc4_ctx)
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static int crypto_arc4_setkey(struct crypto_lskcipher *tfm, const u8 *in_key,
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unsigned int key_len)
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{
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struct arc4_ctx *ctx = crypto_lskcipher_ctx(tfm);
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return arc4_setkey(ctx, in_key, key_len);
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}
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static int crypto_arc4_crypt(struct crypto_lskcipher *tfm, const u8 *src,
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u8 *dst, unsigned nbytes, u8 *siv, u32 flags)
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{
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struct arc4_ctx *ctx = crypto_lskcipher_ctx(tfm);
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if (!(flags & CRYPTO_LSKCIPHER_FLAG_CONT))
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memcpy(siv, ctx, sizeof(*ctx));
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ctx = (struct arc4_ctx *)siv;
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arc4_crypt(ctx, dst, src, nbytes);
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return 0;
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}
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static int crypto_arc4_init(struct crypto_lskcipher *tfm)
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{
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pr_warn_ratelimited("\"%s\" (%ld) uses obsolete ecb(arc4) skcipher\n",
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current->comm, (unsigned long)current->pid);
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return 0;
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}
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static struct lskcipher_alg arc4_alg = {
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.co.base.cra_name = "arc4",
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.co.base.cra_driver_name = "arc4-generic",
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.co.base.cra_priority = 100,
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.co.base.cra_blocksize = ARC4_BLOCK_SIZE,
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.co.base.cra_ctxsize = sizeof(struct arc4_ctx),
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.co.base.cra_alignmask = ARC4_ALIGN - 1,
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.co.base.cra_module = THIS_MODULE,
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.co.min_keysize = ARC4_MIN_KEY_SIZE,
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.co.max_keysize = ARC4_MAX_KEY_SIZE,
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.co.statesize = sizeof(struct arc4_ctx),
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.setkey = crypto_arc4_setkey,
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.encrypt = crypto_arc4_crypt,
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.decrypt = crypto_arc4_crypt,
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.init = crypto_arc4_init,
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};
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static int __init arc4_init(void)
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{
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return crypto_register_lskcipher(&arc4_alg);
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}
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static void __exit arc4_exit(void)
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{
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crypto_unregister_lskcipher(&arc4_alg);
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}
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subsys_initcall(arc4_init);
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module_exit(arc4_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("ARC4 Cipher Algorithm");
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MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>");
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MODULE_ALIAS_CRYPTO("ecb(arc4)");
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