linux/crypto/ccm.c

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/*
* CCM: Counter with CBC-MAC
*
* (C) Copyright IBM Corp. 2007 - Joy Latten <latten@us.ibm.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
*/
#include <crypto/internal/aead.h>
#include <crypto/internal/skcipher.h>
#include <crypto/scatterwalk.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include "internal.h"
struct ccm_instance_ctx {
struct crypto_skcipher_spawn ctr;
struct crypto_spawn cipher;
};
struct crypto_ccm_ctx {
struct crypto_cipher *cipher;
struct crypto_skcipher *ctr;
};
struct crypto_rfc4309_ctx {
struct crypto_aead *child;
u8 nonce[3];
};
struct crypto_rfc4309_req_ctx {
struct scatterlist src[3];
struct scatterlist dst[3];
struct aead_request subreq;
};
struct crypto_ccm_req_priv_ctx {
u8 odata[16];
u8 idata[16];
u8 auth_tag[16];
u32 ilen;
u32 flags;
struct scatterlist src[3];
struct scatterlist dst[3];
struct skcipher_request skreq;
};
static inline struct crypto_ccm_req_priv_ctx *crypto_ccm_reqctx(
struct aead_request *req)
{
unsigned long align = crypto_aead_alignmask(crypto_aead_reqtfm(req));
return (void *)PTR_ALIGN((u8 *)aead_request_ctx(req), align + 1);
}
static int set_msg_len(u8 *block, unsigned int msglen, int csize)
{
__be32 data;
memset(block, 0, csize);
block += csize;
if (csize >= 4)
csize = 4;
else if (msglen > (1 << (8 * csize)))
return -EOVERFLOW;
data = cpu_to_be32(msglen);
memcpy(block - csize, (u8 *)&data + 4 - csize, csize);
return 0;
}
static int crypto_ccm_setkey(struct crypto_aead *aead, const u8 *key,
unsigned int keylen)
{
struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
struct crypto_skcipher *ctr = ctx->ctr;
struct crypto_cipher *tfm = ctx->cipher;
int err = 0;
crypto_skcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK);
crypto_skcipher_set_flags(ctr, crypto_aead_get_flags(aead) &
CRYPTO_TFM_REQ_MASK);
err = crypto_skcipher_setkey(ctr, key, keylen);
crypto_aead_set_flags(aead, crypto_skcipher_get_flags(ctr) &
CRYPTO_TFM_RES_MASK);
if (err)
goto out;
crypto_cipher_clear_flags(tfm, CRYPTO_TFM_REQ_MASK);
crypto_cipher_set_flags(tfm, crypto_aead_get_flags(aead) &
CRYPTO_TFM_REQ_MASK);
err = crypto_cipher_setkey(tfm, key, keylen);
crypto_aead_set_flags(aead, crypto_cipher_get_flags(tfm) &
CRYPTO_TFM_RES_MASK);
out:
return err;
}
static int crypto_ccm_setauthsize(struct crypto_aead *tfm,
unsigned int authsize)
{
switch (authsize) {
case 4:
case 6:
case 8:
case 10:
case 12:
case 14:
case 16:
break;
default:
return -EINVAL;
}
return 0;
}
static int format_input(u8 *info, struct aead_request *req,
unsigned int cryptlen)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
unsigned int lp = req->iv[0];
unsigned int l = lp + 1;
unsigned int m;
m = crypto_aead_authsize(aead);
memcpy(info, req->iv, 16);
/* format control info per RFC 3610 and
* NIST Special Publication 800-38C
*/
*info |= (8 * ((m - 2) / 2));
if (req->assoclen)
*info |= 64;
return set_msg_len(info + 16 - l, cryptlen, l);
}
static int format_adata(u8 *adata, unsigned int a)
{
int len = 0;
/* add control info for associated data
* RFC 3610 and NIST Special Publication 800-38C
*/
if (a < 65280) {
*(__be16 *)adata = cpu_to_be16(a);
len = 2;
} else {
*(__be16 *)adata = cpu_to_be16(0xfffe);
*(__be32 *)&adata[2] = cpu_to_be32(a);
len = 6;
}
return len;
}
static void compute_mac(struct crypto_cipher *tfm, u8 *data, int n,
struct crypto_ccm_req_priv_ctx *pctx)
{
unsigned int bs = 16;
u8 *odata = pctx->odata;
u8 *idata = pctx->idata;
int datalen, getlen;
datalen = n;
/* first time in here, block may be partially filled. */
getlen = bs - pctx->ilen;
if (datalen >= getlen) {
memcpy(idata + pctx->ilen, data, getlen);
crypto_xor(odata, idata, bs);
crypto_cipher_encrypt_one(tfm, odata, odata);
datalen -= getlen;
data += getlen;
pctx->ilen = 0;
}
/* now encrypt rest of data */
while (datalen >= bs) {
crypto_xor(odata, data, bs);
crypto_cipher_encrypt_one(tfm, odata, odata);
datalen -= bs;
data += bs;
}
/* check and see if there's leftover data that wasn't
* enough to fill a block.
*/
if (datalen) {
memcpy(idata + pctx->ilen, data, datalen);
pctx->ilen += datalen;
}
}
static void get_data_to_compute(struct crypto_cipher *tfm,
struct crypto_ccm_req_priv_ctx *pctx,
struct scatterlist *sg, unsigned int len)
{
struct scatter_walk walk;
u8 *data_src;
int n;
scatterwalk_start(&walk, sg);
while (len) {
n = scatterwalk_clamp(&walk, len);
if (!n) {
scatterwalk_start(&walk, sg_next(walk.sg));
n = scatterwalk_clamp(&walk, len);
}
data_src = scatterwalk_map(&walk);
compute_mac(tfm, data_src, n, pctx);
len -= n;
scatterwalk_unmap(data_src);
scatterwalk_advance(&walk, n);
scatterwalk_done(&walk, 0, len);
if (len)
crypto_yield(pctx->flags);
}
/* any leftover needs padding and then encrypted */
if (pctx->ilen) {
int padlen;
u8 *odata = pctx->odata;
u8 *idata = pctx->idata;
padlen = 16 - pctx->ilen;
memset(idata + pctx->ilen, 0, padlen);
crypto_xor(odata, idata, 16);
crypto_cipher_encrypt_one(tfm, odata, odata);
pctx->ilen = 0;
}
}
static int crypto_ccm_auth(struct aead_request *req, struct scatterlist *plain,
unsigned int cryptlen)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
struct crypto_cipher *cipher = ctx->cipher;
unsigned int assoclen = req->assoclen;
u8 *odata = pctx->odata;
u8 *idata = pctx->idata;
int err;
/* format control data for input */
err = format_input(odata, req, cryptlen);
if (err)
goto out;
/* encrypt first block to use as start in computing mac */
crypto_cipher_encrypt_one(cipher, odata, odata);
/* format associated data and compute into mac */
if (assoclen) {
pctx->ilen = format_adata(idata, assoclen);
get_data_to_compute(cipher, pctx, req->src, req->assoclen);
crypto: ccm - Fix handling of null assoc data Its a valid use case to have null associated data in a ccm vector, but this case isn't being handled properly right now. The following ccm decryption/verification test vector, using the rfc4309 implementation regularly triggers a panic, as will any other vector with null assoc data: * key: ab2f8a74b71cd2b1ff802e487d82f8b9 * iv: c6fb7d800d13abd8a6b2d8 * Associated Data: [NULL] * Tag Length: 8 * input: d5e8939fc7892e2b The resulting panic looks like so: Unable to handle kernel paging request at ffff810064ddaec0 RIP: [<ffffffff8864c4d7>] :ccm:get_data_to_compute+0x1a6/0x1d6 PGD 8063 PUD 0 Oops: 0002 [1] SMP last sysfs file: /module/libata/version CPU 0 Modules linked in: crypto_tester_kmod(U) seqiv krng ansi_cprng chainiv rng ctr aes_generic aes_x86_64 ccm cryptomgr testmgr_cipher testmgr aead crypto_blkcipher crypto_a lgapi des ipv6 xfrm_nalgo crypto_api autofs4 hidp l2cap bluetooth nfs lockd fscache nfs_acl sunrpc ip_conntrack_netbios_ns ipt_REJECT xt_state ip_conntrack nfnetlink xt_ tcpudp iptable_filter ip_tables x_tables dm_mirror dm_log dm_multipath scsi_dh dm_mod video hwmon backlight sbs i2c_ec button battery asus_acpi acpi_memhotplug ac lp sg snd_intel8x0 snd_ac97_codec ac97_bus snd_seq_dummy snd_seq_oss joydev snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss ide_cd snd_pcm floppy parport_p c shpchp e752x_edac snd_timer e1000 i2c_i801 edac_mc snd soundcore snd_page_alloc i2c_core cdrom parport serio_raw pcspkr ata_piix libata sd_mod scsi_mod ext3 jbd uhci_h cd ohci_hcd ehci_hcd Pid: 12844, comm: crypto-tester Tainted: G 2.6.18-128.el5.fips1 #1 RIP: 0010:[<ffffffff8864c4d7>] [<ffffffff8864c4d7>] :ccm:get_data_to_compute+0x1a6/0x1d6 RSP: 0018:ffff8100134434e8 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8100104898b0 RCX: ffffffffab6aea10 RDX: 0000000000000010 RSI: ffff8100104898c0 RDI: ffff810064ddaec0 RBP: 0000000000000000 R08: ffff8100104898b0 R09: 0000000000000000 R10: ffff8100103bac84 R11: ffff8100104898b0 R12: ffff810010489858 R13: ffff8100104898b0 R14: ffff8100103bac00 R15: 0000000000000000 FS: 00002ab881adfd30(0000) GS:ffffffff803ac000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: ffff810064ddaec0 CR3: 0000000012a88000 CR4: 00000000000006e0 Process crypto-tester (pid: 12844, threadinfo ffff810013442000, task ffff81003d165860) Stack: ffff8100103bac00 ffff8100104898e8 ffff8100134436f8 ffffffff00000000 0000000000000000 ffff8100104898b0 0000000000000000 ffff810010489858 0000000000000000 ffff8100103bac00 ffff8100134436f8 ffffffff8864c634 Call Trace: [<ffffffff8864c634>] :ccm:crypto_ccm_auth+0x12d/0x140 [<ffffffff8864cf73>] :ccm:crypto_ccm_decrypt+0x161/0x23a [<ffffffff88633643>] :crypto_tester_kmod:cavs_test_rfc4309_ccm+0x4a5/0x559 [...] The above is from a RHEL5-based kernel, but upstream is susceptible too. The fix is trivial: in crypto/ccm.c:crypto_ccm_auth(), pctx->ilen contains whatever was in memory when pctx was allocated if assoclen is 0. The tested fix is to simply add an else clause setting pctx->ilen to 0 for the assoclen == 0 case, so that get_data_to_compute() doesn't try doing things its not supposed to. Signed-off-by: Jarod Wilson <jarod@redhat.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2009-01-22 08:58:15 +00:00
} else {
pctx->ilen = 0;
}
/* compute plaintext into mac */
crypto: ccm - Fix handling of zero plaintext when computing mac There are cases when cryptlen can be zero in crypto_ccm_auth(): -encryptiom: input scatterlist length is zero (no plaintext) -decryption: input scatterlist contains only the mac plus the condition of having different source and destination buffers (or else scatterlist length = max(plaintext_len, ciphertext_len)). These are not handled correctly, leading to crashes like: root@p4080ds:~/crypto# insmod tcrypt.ko mode=45 ------------[ cut here ]------------ kernel BUG at crypto/scatterwalk.c:37! Oops: Exception in kernel mode, sig: 5 [#1] SMP NR_CPUS=8 P4080 DS Modules linked in: tcrypt(+) crc32c xts xcbc vmac pcbc ecb gcm ghash_generic gf128mul ccm ctr seqiv CPU: 3 PID: 1082 Comm: cryptomgr_test Not tainted 3.11.0 #14 task: ee12c5b0 ti: eecd0000 task.ti: eecd0000 NIP: c0204d98 LR: f9225848 CTR: c0204d80 REGS: eecd1b70 TRAP: 0700 Not tainted (3.11.0) MSR: 00029002 <CE,EE,ME> CR: 22044022 XER: 20000000 GPR00: f9225c94 eecd1c20 ee12c5b0 eecd1c28 ee879400 ee879400 00000000 ee607464 GPR08: 00000001 00000001 00000000 006b0000 c0204d80 00000000 00000002 c0698e20 GPR16: ee987000 ee895000 fffffff4 ee879500 00000100 eecd1d58 00000001 00000000 GPR24: ee879400 00000020 00000000 00000000 ee5b2800 ee607430 00000004 ee607460 NIP [c0204d98] scatterwalk_start+0x18/0x30 LR [f9225848] get_data_to_compute+0x28/0x2f0 [ccm] Call Trace: [eecd1c20] [f9225974] get_data_to_compute+0x154/0x2f0 [ccm] (unreliable) [eecd1c70] [f9225c94] crypto_ccm_auth+0x184/0x1d0 [ccm] [eecd1cb0] [f9225d40] crypto_ccm_encrypt+0x60/0x2d0 [ccm] [eecd1cf0] [c020d77c] __test_aead+0x3ec/0xe20 [eecd1e20] [c020f35c] test_aead+0x6c/0xe0 [eecd1e40] [c020f420] alg_test_aead+0x50/0xd0 [eecd1e60] [c020e5e4] alg_test+0x114/0x2e0 [eecd1ee0] [c020bd1c] cryptomgr_test+0x4c/0x60 [eecd1ef0] [c0047058] kthread+0xa8/0xb0 [eecd1f40] [c000eb0c] ret_from_kernel_thread+0x5c/0x64 Instruction dump: 0f080000 81290024 552807fe 0f080000 5529003a 4bffffb4 90830000 39400000 39000001 8124000c 2f890000 7d28579e <0f090000> 81240008 91230004 4e800020 ---[ end trace 6d652dfcd1be37bd ]--- Cc: <stable@vger.kernel.org> Cc: Jussi Kivilinna <jussi.kivilinna@mbnet.fi> Signed-off-by: Horia Geanta <horia.geanta@freescale.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2013-11-28 13:11:15 +00:00
if (cryptlen)
get_data_to_compute(cipher, pctx, plain, cryptlen);
out:
return err;
}
static void crypto_ccm_encrypt_done(struct crypto_async_request *areq, int err)
{
struct aead_request *req = areq->data;
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
u8 *odata = pctx->odata;
if (!err)
scatterwalk_map_and_copy(odata, req->dst,
req->assoclen + req->cryptlen,
crypto_aead_authsize(aead), 1);
aead_request_complete(req, err);
}
static inline int crypto_ccm_check_iv(const u8 *iv)
{
/* 2 <= L <= 8, so 1 <= L' <= 7. */
if (1 > iv[0] || iv[0] > 7)
return -EINVAL;
return 0;
}
static int crypto_ccm_init_crypt(struct aead_request *req, u8 *tag)
{
struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
struct scatterlist *sg;
u8 *iv = req->iv;
int err;
err = crypto_ccm_check_iv(iv);
if (err)
return err;
pctx->flags = aead_request_flags(req);
/* Note: rfc 3610 and NIST 800-38C require counter of
* zero to encrypt auth tag.
*/
memset(iv + 15 - iv[0], 0, iv[0] + 1);
sg_init_table(pctx->src, 3);
sg_set_buf(pctx->src, tag, 16);
sg = scatterwalk_ffwd(pctx->src + 1, req->src, req->assoclen);
if (sg != pctx->src + 1)
sg_chain(pctx->src, 2, sg);
if (req->src != req->dst) {
sg_init_table(pctx->dst, 3);
sg_set_buf(pctx->dst, tag, 16);
sg = scatterwalk_ffwd(pctx->dst + 1, req->dst, req->assoclen);
if (sg != pctx->dst + 1)
sg_chain(pctx->dst, 2, sg);
}
return 0;
}
static int crypto_ccm_encrypt(struct aead_request *req)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
struct skcipher_request *skreq = &pctx->skreq;
struct scatterlist *dst;
unsigned int cryptlen = req->cryptlen;
u8 *odata = pctx->odata;
u8 *iv = req->iv;
int err;
err = crypto_ccm_init_crypt(req, odata);
if (err)
return err;
err = crypto_ccm_auth(req, sg_next(pctx->src), cryptlen);
if (err)
return err;
dst = pctx->src;
if (req->src != req->dst)
dst = pctx->dst;
skcipher_request_set_tfm(skreq, ctx->ctr);
skcipher_request_set_callback(skreq, pctx->flags,
crypto_ccm_encrypt_done, req);
skcipher_request_set_crypt(skreq, pctx->src, dst, cryptlen + 16, iv);
err = crypto_skcipher_encrypt(skreq);
if (err)
return err;
/* copy authtag to end of dst */
scatterwalk_map_and_copy(odata, sg_next(dst), cryptlen,
crypto_aead_authsize(aead), 1);
return err;
}
static void crypto_ccm_decrypt_done(struct crypto_async_request *areq,
int err)
{
struct aead_request *req = areq->data;
struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
struct crypto_aead *aead = crypto_aead_reqtfm(req);
unsigned int authsize = crypto_aead_authsize(aead);
unsigned int cryptlen = req->cryptlen - authsize;
struct scatterlist *dst;
pctx->flags = 0;
dst = sg_next(req->src == req->dst ? pctx->src : pctx->dst);
if (!err) {
err = crypto_ccm_auth(req, dst, cryptlen);
crypto: crypto_memneq - add equality testing of memory regions w/o timing leaks When comparing MAC hashes, AEAD authentication tags, or other hash values in the context of authentication or integrity checking, it is important not to leak timing information to a potential attacker, i.e. when communication happens over a network. Bytewise memory comparisons (such as memcmp) are usually optimized so that they return a nonzero value as soon as a mismatch is found. E.g, on x86_64/i5 for 512 bytes this can be ~50 cyc for a full mismatch and up to ~850 cyc for a full match (cold). This early-return behavior can leak timing information as a side channel, allowing an attacker to iteratively guess the correct result. This patch adds a new method crypto_memneq ("memory not equal to each other") to the crypto API that compares memory areas of the same length in roughly "constant time" (cache misses could change the timing, but since they don't reveal information about the content of the strings being compared, they are effectively benign). Iow, best and worst case behaviour take the same amount of time to complete (in contrast to memcmp). Note that crypto_memneq (unlike memcmp) can only be used to test for equality or inequality, NOT for lexicographical order. This, however, is not an issue for its use-cases within the crypto API. We tried to locate all of the places in the crypto API where memcmp was being used for authentication or integrity checking, and convert them over to crypto_memneq. crypto_memneq is declared noinline, placed in its own source file, and compiled with optimizations that might increase code size disabled ("Os") because a smart compiler (or LTO) might notice that the return value is always compared against zero/nonzero, and might then reintroduce the same early-return optimization that we are trying to avoid. Using #pragma or __attribute__ optimization annotations of the code for disabling optimization was avoided as it seems to be considered broken or unmaintained for long time in GCC [1]. Therefore, we work around that by specifying the compile flag for memneq.o directly in the Makefile. We found that this seems to be most appropriate. As we use ("Os"), this patch also provides a loop-free "fast-path" for frequently used 16 byte digests. Similarly to kernel library string functions, leave an option for future even further optimized architecture specific assembler implementations. This was a joint work of James Yonan and Daniel Borkmann. Also thanks for feedback from Florian Weimer on this and earlier proposals [2]. [1] http://gcc.gnu.org/ml/gcc/2012-07/msg00211.html [2] https://lkml.org/lkml/2013/2/10/131 Signed-off-by: James Yonan <james@openvpn.net> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Florian Weimer <fw@deneb.enyo.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2013-09-26 08:20:39 +00:00
if (!err && crypto_memneq(pctx->auth_tag, pctx->odata, authsize))
err = -EBADMSG;
}
aead_request_complete(req, err);
}
static int crypto_ccm_decrypt(struct aead_request *req)
{
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_ccm_ctx *ctx = crypto_aead_ctx(aead);
struct crypto_ccm_req_priv_ctx *pctx = crypto_ccm_reqctx(req);
struct skcipher_request *skreq = &pctx->skreq;
struct scatterlist *dst;
unsigned int authsize = crypto_aead_authsize(aead);
unsigned int cryptlen = req->cryptlen;
u8 *authtag = pctx->auth_tag;
u8 *odata = pctx->odata;
u8 *iv = req->iv;
int err;
cryptlen -= authsize;
err = crypto_ccm_init_crypt(req, authtag);
if (err)
return err;
scatterwalk_map_and_copy(authtag, sg_next(pctx->src), cryptlen,
authsize, 0);
dst = pctx->src;
if (req->src != req->dst)
dst = pctx->dst;
skcipher_request_set_tfm(skreq, ctx->ctr);
skcipher_request_set_callback(skreq, pctx->flags,
crypto_ccm_decrypt_done, req);
skcipher_request_set_crypt(skreq, pctx->src, dst, cryptlen + 16, iv);
err = crypto_skcipher_decrypt(skreq);
if (err)
return err;
err = crypto_ccm_auth(req, sg_next(dst), cryptlen);
if (err)
return err;
/* verify */
crypto: crypto_memneq - add equality testing of memory regions w/o timing leaks When comparing MAC hashes, AEAD authentication tags, or other hash values in the context of authentication or integrity checking, it is important not to leak timing information to a potential attacker, i.e. when communication happens over a network. Bytewise memory comparisons (such as memcmp) are usually optimized so that they return a nonzero value as soon as a mismatch is found. E.g, on x86_64/i5 for 512 bytes this can be ~50 cyc for a full mismatch and up to ~850 cyc for a full match (cold). This early-return behavior can leak timing information as a side channel, allowing an attacker to iteratively guess the correct result. This patch adds a new method crypto_memneq ("memory not equal to each other") to the crypto API that compares memory areas of the same length in roughly "constant time" (cache misses could change the timing, but since they don't reveal information about the content of the strings being compared, they are effectively benign). Iow, best and worst case behaviour take the same amount of time to complete (in contrast to memcmp). Note that crypto_memneq (unlike memcmp) can only be used to test for equality or inequality, NOT for lexicographical order. This, however, is not an issue for its use-cases within the crypto API. We tried to locate all of the places in the crypto API where memcmp was being used for authentication or integrity checking, and convert them over to crypto_memneq. crypto_memneq is declared noinline, placed in its own source file, and compiled with optimizations that might increase code size disabled ("Os") because a smart compiler (or LTO) might notice that the return value is always compared against zero/nonzero, and might then reintroduce the same early-return optimization that we are trying to avoid. Using #pragma or __attribute__ optimization annotations of the code for disabling optimization was avoided as it seems to be considered broken or unmaintained for long time in GCC [1]. Therefore, we work around that by specifying the compile flag for memneq.o directly in the Makefile. We found that this seems to be most appropriate. As we use ("Os"), this patch also provides a loop-free "fast-path" for frequently used 16 byte digests. Similarly to kernel library string functions, leave an option for future even further optimized architecture specific assembler implementations. This was a joint work of James Yonan and Daniel Borkmann. Also thanks for feedback from Florian Weimer on this and earlier proposals [2]. [1] http://gcc.gnu.org/ml/gcc/2012-07/msg00211.html [2] https://lkml.org/lkml/2013/2/10/131 Signed-off-by: James Yonan <james@openvpn.net> Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Cc: Florian Weimer <fw@deneb.enyo.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2013-09-26 08:20:39 +00:00
if (crypto_memneq(authtag, odata, authsize))
return -EBADMSG;
return err;
}
static int crypto_ccm_init_tfm(struct crypto_aead *tfm)
{
struct aead_instance *inst = aead_alg_instance(tfm);
struct ccm_instance_ctx *ictx = aead_instance_ctx(inst);
struct crypto_ccm_ctx *ctx = crypto_aead_ctx(tfm);
struct crypto_cipher *cipher;
struct crypto_skcipher *ctr;
unsigned long align;
int err;
cipher = crypto_spawn_cipher(&ictx->cipher);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
ctr = crypto_spawn_skcipher2(&ictx->ctr);
err = PTR_ERR(ctr);
if (IS_ERR(ctr))
goto err_free_cipher;
ctx->cipher = cipher;
ctx->ctr = ctr;
align = crypto_aead_alignmask(tfm);
align &= ~(crypto_tfm_ctx_alignment() - 1);
crypto_aead_set_reqsize(
tfm,
align + sizeof(struct crypto_ccm_req_priv_ctx) +
crypto_skcipher_reqsize(ctr));
return 0;
err_free_cipher:
crypto_free_cipher(cipher);
return err;
}
static void crypto_ccm_exit_tfm(struct crypto_aead *tfm)
{
struct crypto_ccm_ctx *ctx = crypto_aead_ctx(tfm);
crypto_free_cipher(ctx->cipher);
crypto_free_skcipher(ctx->ctr);
}
static void crypto_ccm_free(struct aead_instance *inst)
{
struct ccm_instance_ctx *ctx = aead_instance_ctx(inst);
crypto_drop_spawn(&ctx->cipher);
crypto_drop_skcipher(&ctx->ctr);
kfree(inst);
}
static int crypto_ccm_create_common(struct crypto_template *tmpl,
struct rtattr **tb,
const char *full_name,
const char *ctr_name,
const char *cipher_name)
{
struct crypto_attr_type *algt;
struct aead_instance *inst;
struct skcipher_alg *ctr;
struct crypto_alg *cipher;
struct ccm_instance_ctx *ictx;
int err;
algt = crypto_get_attr_type(tb);
if (IS_ERR(algt))
return PTR_ERR(algt);
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
return -EINVAL;
cipher = crypto_alg_mod_lookup(cipher_name, CRYPTO_ALG_TYPE_CIPHER,
CRYPTO_ALG_TYPE_MASK);
if (IS_ERR(cipher))
return PTR_ERR(cipher);
err = -EINVAL;
if (cipher->cra_blocksize != 16)
goto out_put_cipher;
inst = kzalloc(sizeof(*inst) + sizeof(*ictx), GFP_KERNEL);
err = -ENOMEM;
if (!inst)
goto out_put_cipher;
ictx = aead_instance_ctx(inst);
err = crypto_init_spawn(&ictx->cipher, cipher,
aead_crypto_instance(inst),
CRYPTO_ALG_TYPE_MASK);
if (err)
goto err_free_inst;
crypto_set_skcipher_spawn(&ictx->ctr, aead_crypto_instance(inst));
err = crypto_grab_skcipher2(&ictx->ctr, ctr_name, 0,
crypto_requires_sync(algt->type,
algt->mask));
if (err)
goto err_drop_cipher;
ctr = crypto_spawn_skcipher_alg(&ictx->ctr);
/* Not a stream cipher? */
err = -EINVAL;
if (ctr->base.cra_blocksize != 1)
goto err_drop_ctr;
/* We want the real thing! */
if (crypto_skcipher_alg_ivsize(ctr) != 16)
goto err_drop_ctr;
err = -ENAMETOOLONG;
if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
"ccm_base(%s,%s)", ctr->base.cra_driver_name,
cipher->cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
goto err_drop_ctr;
memcpy(inst->alg.base.cra_name, full_name, CRYPTO_MAX_ALG_NAME);
inst->alg.base.cra_flags = ctr->base.cra_flags & CRYPTO_ALG_ASYNC;
inst->alg.base.cra_priority = (cipher->cra_priority +
ctr->base.cra_priority) / 2;
inst->alg.base.cra_blocksize = 1;
inst->alg.base.cra_alignmask = cipher->cra_alignmask |
ctr->base.cra_alignmask |
(__alignof__(u32) - 1);
inst->alg.ivsize = 16;
inst->alg.chunksize = crypto_skcipher_alg_chunksize(ctr);
inst->alg.maxauthsize = 16;
inst->alg.base.cra_ctxsize = sizeof(struct crypto_ccm_ctx);
inst->alg.init = crypto_ccm_init_tfm;
inst->alg.exit = crypto_ccm_exit_tfm;
inst->alg.setkey = crypto_ccm_setkey;
inst->alg.setauthsize = crypto_ccm_setauthsize;
inst->alg.encrypt = crypto_ccm_encrypt;
inst->alg.decrypt = crypto_ccm_decrypt;
inst->free = crypto_ccm_free;
err = aead_register_instance(tmpl, inst);
if (err)
goto err_drop_ctr;
out_put_cipher:
crypto_mod_put(cipher);
return err;
err_drop_ctr:
crypto_drop_skcipher(&ictx->ctr);
err_drop_cipher:
crypto_drop_spawn(&ictx->cipher);
err_free_inst:
kfree(inst);
goto out_put_cipher;
}
static int crypto_ccm_create(struct crypto_template *tmpl, struct rtattr **tb)
{
const char *cipher_name;
char ctr_name[CRYPTO_MAX_ALG_NAME];
char full_name[CRYPTO_MAX_ALG_NAME];
cipher_name = crypto_attr_alg_name(tb[1]);
if (IS_ERR(cipher_name))
return PTR_ERR(cipher_name);
if (snprintf(ctr_name, CRYPTO_MAX_ALG_NAME, "ctr(%s)",
cipher_name) >= CRYPTO_MAX_ALG_NAME)
return -ENAMETOOLONG;
if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm(%s)", cipher_name) >=
CRYPTO_MAX_ALG_NAME)
return -ENAMETOOLONG;
return crypto_ccm_create_common(tmpl, tb, full_name, ctr_name,
cipher_name);
}
static struct crypto_template crypto_ccm_tmpl = {
.name = "ccm",
.create = crypto_ccm_create,
.module = THIS_MODULE,
};
static int crypto_ccm_base_create(struct crypto_template *tmpl,
struct rtattr **tb)
{
const char *ctr_name;
const char *cipher_name;
char full_name[CRYPTO_MAX_ALG_NAME];
ctr_name = crypto_attr_alg_name(tb[1]);
if (IS_ERR(ctr_name))
return PTR_ERR(ctr_name);
cipher_name = crypto_attr_alg_name(tb[2]);
if (IS_ERR(cipher_name))
return PTR_ERR(cipher_name);
if (snprintf(full_name, CRYPTO_MAX_ALG_NAME, "ccm_base(%s,%s)",
ctr_name, cipher_name) >= CRYPTO_MAX_ALG_NAME)
return -ENAMETOOLONG;
return crypto_ccm_create_common(tmpl, tb, full_name, ctr_name,
cipher_name);
}
static struct crypto_template crypto_ccm_base_tmpl = {
.name = "ccm_base",
.create = crypto_ccm_base_create,
.module = THIS_MODULE,
};
static int crypto_rfc4309_setkey(struct crypto_aead *parent, const u8 *key,
unsigned int keylen)
{
struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
struct crypto_aead *child = ctx->child;
int err;
if (keylen < 3)
return -EINVAL;
keylen -= 3;
memcpy(ctx->nonce, key + keylen, 3);
crypto_aead_clear_flags(child, CRYPTO_TFM_REQ_MASK);
crypto_aead_set_flags(child, crypto_aead_get_flags(parent) &
CRYPTO_TFM_REQ_MASK);
err = crypto_aead_setkey(child, key, keylen);
crypto_aead_set_flags(parent, crypto_aead_get_flags(child) &
CRYPTO_TFM_RES_MASK);
return err;
}
static int crypto_rfc4309_setauthsize(struct crypto_aead *parent,
unsigned int authsize)
{
struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(parent);
switch (authsize) {
case 8:
case 12:
case 16:
break;
default:
return -EINVAL;
}
return crypto_aead_setauthsize(ctx->child, authsize);
}
static struct aead_request *crypto_rfc4309_crypt(struct aead_request *req)
{
struct crypto_rfc4309_req_ctx *rctx = aead_request_ctx(req);
struct aead_request *subreq = &rctx->subreq;
struct crypto_aead *aead = crypto_aead_reqtfm(req);
struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(aead);
struct crypto_aead *child = ctx->child;
struct scatterlist *sg;
u8 *iv = PTR_ALIGN((u8 *)(subreq + 1) + crypto_aead_reqsize(child),
crypto_aead_alignmask(child) + 1);
/* L' */
iv[0] = 3;
memcpy(iv + 1, ctx->nonce, 3);
memcpy(iv + 4, req->iv, 8);
scatterwalk_map_and_copy(iv + 16, req->src, 0, req->assoclen - 8, 0);
sg_init_table(rctx->src, 3);
sg_set_buf(rctx->src, iv + 16, req->assoclen - 8);
sg = scatterwalk_ffwd(rctx->src + 1, req->src, req->assoclen);
if (sg != rctx->src + 1)
sg_chain(rctx->src, 2, sg);
if (req->src != req->dst) {
sg_init_table(rctx->dst, 3);
sg_set_buf(rctx->dst, iv + 16, req->assoclen - 8);
sg = scatterwalk_ffwd(rctx->dst + 1, req->dst, req->assoclen);
if (sg != rctx->dst + 1)
sg_chain(rctx->dst, 2, sg);
}
aead_request_set_tfm(subreq, child);
aead_request_set_callback(subreq, req->base.flags, req->base.complete,
req->base.data);
aead_request_set_crypt(subreq, rctx->src,
req->src == req->dst ? rctx->src : rctx->dst,
req->cryptlen, iv);
aead_request_set_ad(subreq, req->assoclen - 8);
return subreq;
}
static int crypto_rfc4309_encrypt(struct aead_request *req)
{
if (req->assoclen != 16 && req->assoclen != 20)
return -EINVAL;
req = crypto_rfc4309_crypt(req);
return crypto_aead_encrypt(req);
}
static int crypto_rfc4309_decrypt(struct aead_request *req)
{
if (req->assoclen != 16 && req->assoclen != 20)
return -EINVAL;
req = crypto_rfc4309_crypt(req);
return crypto_aead_decrypt(req);
}
static int crypto_rfc4309_init_tfm(struct crypto_aead *tfm)
{
struct aead_instance *inst = aead_alg_instance(tfm);
struct crypto_aead_spawn *spawn = aead_instance_ctx(inst);
struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(tfm);
struct crypto_aead *aead;
unsigned long align;
aead = crypto_spawn_aead(spawn);
if (IS_ERR(aead))
return PTR_ERR(aead);
ctx->child = aead;
align = crypto_aead_alignmask(aead);
align &= ~(crypto_tfm_ctx_alignment() - 1);
crypto_aead_set_reqsize(
tfm,
sizeof(struct crypto_rfc4309_req_ctx) +
ALIGN(crypto_aead_reqsize(aead), crypto_tfm_ctx_alignment()) +
align + 32);
return 0;
}
static void crypto_rfc4309_exit_tfm(struct crypto_aead *tfm)
{
struct crypto_rfc4309_ctx *ctx = crypto_aead_ctx(tfm);
crypto_free_aead(ctx->child);
}
static void crypto_rfc4309_free(struct aead_instance *inst)
{
crypto_drop_aead(aead_instance_ctx(inst));
kfree(inst);
}
static int crypto_rfc4309_create(struct crypto_template *tmpl,
struct rtattr **tb)
{
struct crypto_attr_type *algt;
struct aead_instance *inst;
struct crypto_aead_spawn *spawn;
struct aead_alg *alg;
const char *ccm_name;
int err;
algt = crypto_get_attr_type(tb);
if (IS_ERR(algt))
return PTR_ERR(algt);
if ((algt->type ^ CRYPTO_ALG_TYPE_AEAD) & algt->mask)
return -EINVAL;
ccm_name = crypto_attr_alg_name(tb[1]);
if (IS_ERR(ccm_name))
return PTR_ERR(ccm_name);
inst = kzalloc(sizeof(*inst) + sizeof(*spawn), GFP_KERNEL);
if (!inst)
return -ENOMEM;
spawn = aead_instance_ctx(inst);
crypto_set_aead_spawn(spawn, aead_crypto_instance(inst));
err = crypto_grab_aead(spawn, ccm_name, 0,
crypto_requires_sync(algt->type, algt->mask));
if (err)
goto out_free_inst;
alg = crypto_spawn_aead_alg(spawn);
err = -EINVAL;
/* We only support 16-byte blocks. */
if (crypto_aead_alg_ivsize(alg) != 16)
goto out_drop_alg;
/* Not a stream cipher? */
if (alg->base.cra_blocksize != 1)
goto out_drop_alg;
err = -ENAMETOOLONG;
if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
"rfc4309(%s)", alg->base.cra_name) >=
CRYPTO_MAX_ALG_NAME ||
snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
"rfc4309(%s)", alg->base.cra_driver_name) >=
CRYPTO_MAX_ALG_NAME)
goto out_drop_alg;
inst->alg.base.cra_flags = alg->base.cra_flags & CRYPTO_ALG_ASYNC;
inst->alg.base.cra_priority = alg->base.cra_priority;
inst->alg.base.cra_blocksize = 1;
inst->alg.base.cra_alignmask = alg->base.cra_alignmask;
inst->alg.ivsize = 8;
inst->alg.chunksize = crypto_aead_alg_chunksize(alg);
inst->alg.maxauthsize = 16;
inst->alg.base.cra_ctxsize = sizeof(struct crypto_rfc4309_ctx);
inst->alg.init = crypto_rfc4309_init_tfm;
inst->alg.exit = crypto_rfc4309_exit_tfm;
inst->alg.setkey = crypto_rfc4309_setkey;
inst->alg.setauthsize = crypto_rfc4309_setauthsize;
inst->alg.encrypt = crypto_rfc4309_encrypt;
inst->alg.decrypt = crypto_rfc4309_decrypt;
inst->free = crypto_rfc4309_free;
err = aead_register_instance(tmpl, inst);
if (err)
goto out_drop_alg;
out:
return err;
out_drop_alg:
crypto_drop_aead(spawn);
out_free_inst:
kfree(inst);
goto out;
}
static struct crypto_template crypto_rfc4309_tmpl = {
.name = "rfc4309",
.create = crypto_rfc4309_create,
.module = THIS_MODULE,
};
static int __init crypto_ccm_module_init(void)
{
int err;
err = crypto_register_template(&crypto_ccm_base_tmpl);
if (err)
goto out;
err = crypto_register_template(&crypto_ccm_tmpl);
if (err)
goto out_undo_base;
err = crypto_register_template(&crypto_rfc4309_tmpl);
if (err)
goto out_undo_ccm;
out:
return err;
out_undo_ccm:
crypto_unregister_template(&crypto_ccm_tmpl);
out_undo_base:
crypto_unregister_template(&crypto_ccm_base_tmpl);
goto out;
}
static void __exit crypto_ccm_module_exit(void)
{
crypto_unregister_template(&crypto_rfc4309_tmpl);
crypto_unregister_template(&crypto_ccm_tmpl);
crypto_unregister_template(&crypto_ccm_base_tmpl);
}
module_init(crypto_ccm_module_init);
module_exit(crypto_ccm_module_exit);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Counter with CBC MAC");
MODULE_ALIAS_CRYPTO("ccm_base");
MODULE_ALIAS_CRYPTO("rfc4309");
MODULE_ALIAS_CRYPTO("ccm");