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![Eric Biggers](/assets/img/avatar_default.png)
The CRYPTO_TFM_RES_BAD_KEY_LEN flag was apparently meant as a way to make the ->setkey() functions provide more information about errors. However, no one actually checks for this flag, which makes it pointless. Also, many algorithms fail to set this flag when given a bad length key. Reviewing just the generic implementations, this is the case for aes-fixed-time, cbcmac, echainiv, nhpoly1305, pcrypt, rfc3686, rfc4309, rfc7539, rfc7539esp, salsa20, seqiv, and xcbc. But there are probably many more in arch/*/crypto/ and drivers/crypto/. Some algorithms can even set this flag when the key is the correct length. For example, authenc and authencesn set it when the key payload is malformed in any way (not just a bad length), the atmel-sha and ccree drivers can set it if a memory allocation fails, and the chelsio driver sets it for bad auth tag lengths, not just bad key lengths. So even if someone actually wanted to start checking this flag (which seems unlikely, since it's been unused for a long time), there would be a lot of work needed to get it working correctly. But it would probably be much better to go back to the drawing board and just define different return values, like -EINVAL if the key is invalid for the algorithm vs. -EKEYREJECTED if the key was rejected by a policy like "no weak keys". That would be much simpler, less error-prone, and easier to test. So just remove this flag. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Horia Geantă <horia.geanta@nxp.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
106 lines
2.4 KiB
C
106 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <crypto/internal/hash.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/xxhash.h>
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#include <asm/unaligned.h>
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#define XXHASH64_BLOCK_SIZE 32
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#define XXHASH64_DIGEST_SIZE 8
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struct xxhash64_tfm_ctx {
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u64 seed;
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};
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struct xxhash64_desc_ctx {
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struct xxh64_state xxhstate;
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};
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static int xxhash64_setkey(struct crypto_shash *tfm, const u8 *key,
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unsigned int keylen)
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{
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struct xxhash64_tfm_ctx *tctx = crypto_shash_ctx(tfm);
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if (keylen != sizeof(tctx->seed))
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return -EINVAL;
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tctx->seed = get_unaligned_le64(key);
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return 0;
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}
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static int xxhash64_init(struct shash_desc *desc)
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{
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struct xxhash64_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
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struct xxhash64_desc_ctx *dctx = shash_desc_ctx(desc);
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xxh64_reset(&dctx->xxhstate, tctx->seed);
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return 0;
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}
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static int xxhash64_update(struct shash_desc *desc, const u8 *data,
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unsigned int length)
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{
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struct xxhash64_desc_ctx *dctx = shash_desc_ctx(desc);
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xxh64_update(&dctx->xxhstate, data, length);
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return 0;
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}
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static int xxhash64_final(struct shash_desc *desc, u8 *out)
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{
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struct xxhash64_desc_ctx *dctx = shash_desc_ctx(desc);
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put_unaligned_le64(xxh64_digest(&dctx->xxhstate), out);
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return 0;
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}
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static int xxhash64_digest(struct shash_desc *desc, const u8 *data,
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unsigned int length, u8 *out)
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{
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struct xxhash64_tfm_ctx *tctx = crypto_shash_ctx(desc->tfm);
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put_unaligned_le64(xxh64(data, length, tctx->seed), out);
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return 0;
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}
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static struct shash_alg alg = {
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.digestsize = XXHASH64_DIGEST_SIZE,
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.setkey = xxhash64_setkey,
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.init = xxhash64_init,
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.update = xxhash64_update,
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.final = xxhash64_final,
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.digest = xxhash64_digest,
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.descsize = sizeof(struct xxhash64_desc_ctx),
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.base = {
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.cra_name = "xxhash64",
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.cra_driver_name = "xxhash64-generic",
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.cra_priority = 100,
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.cra_flags = CRYPTO_ALG_OPTIONAL_KEY,
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.cra_blocksize = XXHASH64_BLOCK_SIZE,
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.cra_ctxsize = sizeof(struct xxhash64_tfm_ctx),
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.cra_module = THIS_MODULE,
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}
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};
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static int __init xxhash_mod_init(void)
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{
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return crypto_register_shash(&alg);
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}
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static void __exit xxhash_mod_fini(void)
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{
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crypto_unregister_shash(&alg);
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}
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subsys_initcall(xxhash_mod_init);
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module_exit(xxhash_mod_fini);
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MODULE_AUTHOR("Nikolay Borisov <nborisov@suse.com>");
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MODULE_DESCRIPTION("xxhash calculations wrapper for lib/xxhash.c");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_CRYPTO("xxhash64");
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MODULE_ALIAS_CRYPTO("xxhash64-generic");
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