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linux-next/net/ceph/crypto.c
Ilya Dryomov aaef31703a libceph: do not crash on large auth tickets
Large (greater than 32k, the value of PAGE_ALLOC_COSTLY_ORDER) auth
tickets will have their buffers vmalloc'ed, which leads to the
following crash in crypto:

[   28.685082] BUG: unable to handle kernel paging request at ffffeb04000032c0
[   28.686032] IP: [<ffffffff81392b42>] scatterwalk_pagedone+0x22/0x80
[   28.686032] PGD 0
[   28.688088] Oops: 0000 [#1] PREEMPT SMP
[   28.688088] Modules linked in:
[   28.688088] CPU: 0 PID: 878 Comm: kworker/0:2 Not tainted 3.17.0-vm+ #305
[   28.688088] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[   28.688088] Workqueue: ceph-msgr con_work
[   28.688088] task: ffff88011a7f9030 ti: ffff8800d903c000 task.ti: ffff8800d903c000
[   28.688088] RIP: 0010:[<ffffffff81392b42>]  [<ffffffff81392b42>] scatterwalk_pagedone+0x22/0x80
[   28.688088] RSP: 0018:ffff8800d903f688  EFLAGS: 00010286
[   28.688088] RAX: ffffeb04000032c0 RBX: ffff8800d903f718 RCX: ffffeb04000032c0
[   28.688088] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8800d903f750
[   28.688088] RBP: ffff8800d903f688 R08: 00000000000007de R09: ffff8800d903f880
[   28.688088] R10: 18df467c72d6257b R11: 0000000000000000 R12: 0000000000000010
[   28.688088] R13: ffff8800d903f750 R14: ffff8800d903f8a0 R15: 0000000000000000
[   28.688088] FS:  00007f50a41c7700(0000) GS:ffff88011fc00000(0000) knlGS:0000000000000000
[   28.688088] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[   28.688088] CR2: ffffeb04000032c0 CR3: 00000000da3f3000 CR4: 00000000000006b0
[   28.688088] Stack:
[   28.688088]  ffff8800d903f698 ffffffff81392ca8 ffff8800d903f6e8 ffffffff81395d32
[   28.688088]  ffff8800dac96000 ffff880000000000 ffff8800d903f980 ffff880119b7e020
[   28.688088]  ffff880119b7e010 0000000000000000 0000000000000010 0000000000000010
[   28.688088] Call Trace:
[   28.688088]  [<ffffffff81392ca8>] scatterwalk_done+0x38/0x40
[   28.688088]  [<ffffffff81392ca8>] scatterwalk_done+0x38/0x40
[   28.688088]  [<ffffffff81395d32>] blkcipher_walk_done+0x182/0x220
[   28.688088]  [<ffffffff813990bf>] crypto_cbc_encrypt+0x15f/0x180
[   28.688088]  [<ffffffff81399780>] ? crypto_aes_set_key+0x30/0x30
[   28.688088]  [<ffffffff8156c40c>] ceph_aes_encrypt2+0x29c/0x2e0
[   28.688088]  [<ffffffff8156d2a3>] ceph_encrypt2+0x93/0xb0
[   28.688088]  [<ffffffff8156d7da>] ceph_x_encrypt+0x4a/0x60
[   28.688088]  [<ffffffff8155b39d>] ? ceph_buffer_new+0x5d/0xf0
[   28.688088]  [<ffffffff8156e837>] ceph_x_build_authorizer.isra.6+0x297/0x360
[   28.688088]  [<ffffffff8112089b>] ? kmem_cache_alloc_trace+0x11b/0x1c0
[   28.688088]  [<ffffffff8156b496>] ? ceph_auth_create_authorizer+0x36/0x80
[   28.688088]  [<ffffffff8156ed83>] ceph_x_create_authorizer+0x63/0xd0
[   28.688088]  [<ffffffff8156b4b4>] ceph_auth_create_authorizer+0x54/0x80
[   28.688088]  [<ffffffff8155f7c0>] get_authorizer+0x80/0xd0
[   28.688088]  [<ffffffff81555a8b>] prepare_write_connect+0x18b/0x2b0
[   28.688088]  [<ffffffff81559289>] try_read+0x1e59/0x1f10

This is because we set up crypto scatterlists as if all buffers were
kmalloc'ed.  Fix it.

Cc: stable@vger.kernel.org
Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
Reviewed-by: Sage Weil <sage@redhat.com>
2014-11-13 22:21:12 +03:00

584 lines
14 KiB
C

#include <linux/ceph/ceph_debug.h>
#include <linux/err.h>
#include <linux/scatterlist.h>
#include <linux/slab.h>
#include <crypto/hash.h>
#include <linux/key-type.h>
#include <keys/ceph-type.h>
#include <keys/user-type.h>
#include <linux/ceph/decode.h>
#include "crypto.h"
int ceph_crypto_key_clone(struct ceph_crypto_key *dst,
const struct ceph_crypto_key *src)
{
memcpy(dst, src, sizeof(struct ceph_crypto_key));
dst->key = kmemdup(src->key, src->len, GFP_NOFS);
if (!dst->key)
return -ENOMEM;
return 0;
}
int ceph_crypto_key_encode(struct ceph_crypto_key *key, void **p, void *end)
{
if (*p + sizeof(u16) + sizeof(key->created) +
sizeof(u16) + key->len > end)
return -ERANGE;
ceph_encode_16(p, key->type);
ceph_encode_copy(p, &key->created, sizeof(key->created));
ceph_encode_16(p, key->len);
ceph_encode_copy(p, key->key, key->len);
return 0;
}
int ceph_crypto_key_decode(struct ceph_crypto_key *key, void **p, void *end)
{
ceph_decode_need(p, end, 2*sizeof(u16) + sizeof(key->created), bad);
key->type = ceph_decode_16(p);
ceph_decode_copy(p, &key->created, sizeof(key->created));
key->len = ceph_decode_16(p);
ceph_decode_need(p, end, key->len, bad);
key->key = kmalloc(key->len, GFP_NOFS);
if (!key->key)
return -ENOMEM;
ceph_decode_copy(p, key->key, key->len);
return 0;
bad:
dout("failed to decode crypto key\n");
return -EINVAL;
}
int ceph_crypto_key_unarmor(struct ceph_crypto_key *key, const char *inkey)
{
int inlen = strlen(inkey);
int blen = inlen * 3 / 4;
void *buf, *p;
int ret;
dout("crypto_key_unarmor %s\n", inkey);
buf = kmalloc(blen, GFP_NOFS);
if (!buf)
return -ENOMEM;
blen = ceph_unarmor(buf, inkey, inkey+inlen);
if (blen < 0) {
kfree(buf);
return blen;
}
p = buf;
ret = ceph_crypto_key_decode(key, &p, p + blen);
kfree(buf);
if (ret)
return ret;
dout("crypto_key_unarmor key %p type %d len %d\n", key,
key->type, key->len);
return 0;
}
#define AES_KEY_SIZE 16
static struct crypto_blkcipher *ceph_crypto_alloc_cipher(void)
{
return crypto_alloc_blkcipher("cbc(aes)", 0, CRYPTO_ALG_ASYNC);
}
static const u8 *aes_iv = (u8 *)CEPH_AES_IV;
/*
* Should be used for buffers allocated with ceph_kvmalloc().
* Currently these are encrypt out-buffer (ceph_buffer) and decrypt
* in-buffer (msg front).
*
* Dispose of @sgt with teardown_sgtable().
*
* @prealloc_sg is to avoid memory allocation inside sg_alloc_table()
* in cases where a single sg is sufficient. No attempt to reduce the
* number of sgs by squeezing physically contiguous pages together is
* made though, for simplicity.
*/
static int setup_sgtable(struct sg_table *sgt, struct scatterlist *prealloc_sg,
const void *buf, unsigned int buf_len)
{
struct scatterlist *sg;
const bool is_vmalloc = is_vmalloc_addr(buf);
unsigned int off = offset_in_page(buf);
unsigned int chunk_cnt = 1;
unsigned int chunk_len = PAGE_ALIGN(off + buf_len);
int i;
int ret;
if (buf_len == 0) {
memset(sgt, 0, sizeof(*sgt));
return -EINVAL;
}
if (is_vmalloc) {
chunk_cnt = chunk_len >> PAGE_SHIFT;
chunk_len = PAGE_SIZE;
}
if (chunk_cnt > 1) {
ret = sg_alloc_table(sgt, chunk_cnt, GFP_NOFS);
if (ret)
return ret;
} else {
WARN_ON(chunk_cnt != 1);
sg_init_table(prealloc_sg, 1);
sgt->sgl = prealloc_sg;
sgt->nents = sgt->orig_nents = 1;
}
for_each_sg(sgt->sgl, sg, sgt->orig_nents, i) {
struct page *page;
unsigned int len = min(chunk_len - off, buf_len);
if (is_vmalloc)
page = vmalloc_to_page(buf);
else
page = virt_to_page(buf);
sg_set_page(sg, page, len, off);
off = 0;
buf += len;
buf_len -= len;
}
WARN_ON(buf_len != 0);
return 0;
}
static void teardown_sgtable(struct sg_table *sgt)
{
if (sgt->orig_nents > 1)
sg_free_table(sgt);
}
static int ceph_aes_encrypt(const void *key, int key_len,
void *dst, size_t *dst_len,
const void *src, size_t src_len)
{
struct scatterlist sg_in[2], prealloc_sg;
struct sg_table sg_out;
struct crypto_blkcipher *tfm = ceph_crypto_alloc_cipher();
struct blkcipher_desc desc = { .tfm = tfm, .flags = 0 };
int ret;
void *iv;
int ivsize;
size_t zero_padding = (0x10 - (src_len & 0x0f));
char pad[16];
if (IS_ERR(tfm))
return PTR_ERR(tfm);
memset(pad, zero_padding, zero_padding);
*dst_len = src_len + zero_padding;
sg_init_table(sg_in, 2);
sg_set_buf(&sg_in[0], src, src_len);
sg_set_buf(&sg_in[1], pad, zero_padding);
ret = setup_sgtable(&sg_out, &prealloc_sg, dst, *dst_len);
if (ret)
goto out_tfm;
crypto_blkcipher_setkey((void *)tfm, key, key_len);
iv = crypto_blkcipher_crt(tfm)->iv;
ivsize = crypto_blkcipher_ivsize(tfm);
memcpy(iv, aes_iv, ivsize);
/*
print_hex_dump(KERN_ERR, "enc key: ", DUMP_PREFIX_NONE, 16, 1,
key, key_len, 1);
print_hex_dump(KERN_ERR, "enc src: ", DUMP_PREFIX_NONE, 16, 1,
src, src_len, 1);
print_hex_dump(KERN_ERR, "enc pad: ", DUMP_PREFIX_NONE, 16, 1,
pad, zero_padding, 1);
*/
ret = crypto_blkcipher_encrypt(&desc, sg_out.sgl, sg_in,
src_len + zero_padding);
if (ret < 0) {
pr_err("ceph_aes_crypt failed %d\n", ret);
goto out_sg;
}
/*
print_hex_dump(KERN_ERR, "enc out: ", DUMP_PREFIX_NONE, 16, 1,
dst, *dst_len, 1);
*/
out_sg:
teardown_sgtable(&sg_out);
out_tfm:
crypto_free_blkcipher(tfm);
return ret;
}
static int ceph_aes_encrypt2(const void *key, int key_len, void *dst,
size_t *dst_len,
const void *src1, size_t src1_len,
const void *src2, size_t src2_len)
{
struct scatterlist sg_in[3], prealloc_sg;
struct sg_table sg_out;
struct crypto_blkcipher *tfm = ceph_crypto_alloc_cipher();
struct blkcipher_desc desc = { .tfm = tfm, .flags = 0 };
int ret;
void *iv;
int ivsize;
size_t zero_padding = (0x10 - ((src1_len + src2_len) & 0x0f));
char pad[16];
if (IS_ERR(tfm))
return PTR_ERR(tfm);
memset(pad, zero_padding, zero_padding);
*dst_len = src1_len + src2_len + zero_padding;
sg_init_table(sg_in, 3);
sg_set_buf(&sg_in[0], src1, src1_len);
sg_set_buf(&sg_in[1], src2, src2_len);
sg_set_buf(&sg_in[2], pad, zero_padding);
ret = setup_sgtable(&sg_out, &prealloc_sg, dst, *dst_len);
if (ret)
goto out_tfm;
crypto_blkcipher_setkey((void *)tfm, key, key_len);
iv = crypto_blkcipher_crt(tfm)->iv;
ivsize = crypto_blkcipher_ivsize(tfm);
memcpy(iv, aes_iv, ivsize);
/*
print_hex_dump(KERN_ERR, "enc key: ", DUMP_PREFIX_NONE, 16, 1,
key, key_len, 1);
print_hex_dump(KERN_ERR, "enc src1: ", DUMP_PREFIX_NONE, 16, 1,
src1, src1_len, 1);
print_hex_dump(KERN_ERR, "enc src2: ", DUMP_PREFIX_NONE, 16, 1,
src2, src2_len, 1);
print_hex_dump(KERN_ERR, "enc pad: ", DUMP_PREFIX_NONE, 16, 1,
pad, zero_padding, 1);
*/
ret = crypto_blkcipher_encrypt(&desc, sg_out.sgl, sg_in,
src1_len + src2_len + zero_padding);
if (ret < 0) {
pr_err("ceph_aes_crypt2 failed %d\n", ret);
goto out_sg;
}
/*
print_hex_dump(KERN_ERR, "enc out: ", DUMP_PREFIX_NONE, 16, 1,
dst, *dst_len, 1);
*/
out_sg:
teardown_sgtable(&sg_out);
out_tfm:
crypto_free_blkcipher(tfm);
return ret;
}
static int ceph_aes_decrypt(const void *key, int key_len,
void *dst, size_t *dst_len,
const void *src, size_t src_len)
{
struct sg_table sg_in;
struct scatterlist sg_out[2], prealloc_sg;
struct crypto_blkcipher *tfm = ceph_crypto_alloc_cipher();
struct blkcipher_desc desc = { .tfm = tfm };
char pad[16];
void *iv;
int ivsize;
int ret;
int last_byte;
if (IS_ERR(tfm))
return PTR_ERR(tfm);
sg_init_table(sg_out, 2);
sg_set_buf(&sg_out[0], dst, *dst_len);
sg_set_buf(&sg_out[1], pad, sizeof(pad));
ret = setup_sgtable(&sg_in, &prealloc_sg, src, src_len);
if (ret)
goto out_tfm;
crypto_blkcipher_setkey((void *)tfm, key, key_len);
iv = crypto_blkcipher_crt(tfm)->iv;
ivsize = crypto_blkcipher_ivsize(tfm);
memcpy(iv, aes_iv, ivsize);
/*
print_hex_dump(KERN_ERR, "dec key: ", DUMP_PREFIX_NONE, 16, 1,
key, key_len, 1);
print_hex_dump(KERN_ERR, "dec in: ", DUMP_PREFIX_NONE, 16, 1,
src, src_len, 1);
*/
ret = crypto_blkcipher_decrypt(&desc, sg_out, sg_in.sgl, src_len);
if (ret < 0) {
pr_err("ceph_aes_decrypt failed %d\n", ret);
goto out_sg;
}
if (src_len <= *dst_len)
last_byte = ((char *)dst)[src_len - 1];
else
last_byte = pad[src_len - *dst_len - 1];
if (last_byte <= 16 && src_len >= last_byte) {
*dst_len = src_len - last_byte;
} else {
pr_err("ceph_aes_decrypt got bad padding %d on src len %d\n",
last_byte, (int)src_len);
return -EPERM; /* bad padding */
}
/*
print_hex_dump(KERN_ERR, "dec out: ", DUMP_PREFIX_NONE, 16, 1,
dst, *dst_len, 1);
*/
out_sg:
teardown_sgtable(&sg_in);
out_tfm:
crypto_free_blkcipher(tfm);
return ret;
}
static int ceph_aes_decrypt2(const void *key, int key_len,
void *dst1, size_t *dst1_len,
void *dst2, size_t *dst2_len,
const void *src, size_t src_len)
{
struct sg_table sg_in;
struct scatterlist sg_out[3], prealloc_sg;
struct crypto_blkcipher *tfm = ceph_crypto_alloc_cipher();
struct blkcipher_desc desc = { .tfm = tfm };
char pad[16];
void *iv;
int ivsize;
int ret;
int last_byte;
if (IS_ERR(tfm))
return PTR_ERR(tfm);
sg_init_table(sg_out, 3);
sg_set_buf(&sg_out[0], dst1, *dst1_len);
sg_set_buf(&sg_out[1], dst2, *dst2_len);
sg_set_buf(&sg_out[2], pad, sizeof(pad));
ret = setup_sgtable(&sg_in, &prealloc_sg, src, src_len);
if (ret)
goto out_tfm;
crypto_blkcipher_setkey((void *)tfm, key, key_len);
iv = crypto_blkcipher_crt(tfm)->iv;
ivsize = crypto_blkcipher_ivsize(tfm);
memcpy(iv, aes_iv, ivsize);
/*
print_hex_dump(KERN_ERR, "dec key: ", DUMP_PREFIX_NONE, 16, 1,
key, key_len, 1);
print_hex_dump(KERN_ERR, "dec in: ", DUMP_PREFIX_NONE, 16, 1,
src, src_len, 1);
*/
ret = crypto_blkcipher_decrypt(&desc, sg_out, sg_in.sgl, src_len);
if (ret < 0) {
pr_err("ceph_aes_decrypt failed %d\n", ret);
goto out_sg;
}
if (src_len <= *dst1_len)
last_byte = ((char *)dst1)[src_len - 1];
else if (src_len <= *dst1_len + *dst2_len)
last_byte = ((char *)dst2)[src_len - *dst1_len - 1];
else
last_byte = pad[src_len - *dst1_len - *dst2_len - 1];
if (last_byte <= 16 && src_len >= last_byte) {
src_len -= last_byte;
} else {
pr_err("ceph_aes_decrypt got bad padding %d on src len %d\n",
last_byte, (int)src_len);
return -EPERM; /* bad padding */
}
if (src_len < *dst1_len) {
*dst1_len = src_len;
*dst2_len = 0;
} else {
*dst2_len = src_len - *dst1_len;
}
/*
print_hex_dump(KERN_ERR, "dec out1: ", DUMP_PREFIX_NONE, 16, 1,
dst1, *dst1_len, 1);
print_hex_dump(KERN_ERR, "dec out2: ", DUMP_PREFIX_NONE, 16, 1,
dst2, *dst2_len, 1);
*/
out_sg:
teardown_sgtable(&sg_in);
out_tfm:
crypto_free_blkcipher(tfm);
return ret;
}
int ceph_decrypt(struct ceph_crypto_key *secret, void *dst, size_t *dst_len,
const void *src, size_t src_len)
{
switch (secret->type) {
case CEPH_CRYPTO_NONE:
if (*dst_len < src_len)
return -ERANGE;
memcpy(dst, src, src_len);
*dst_len = src_len;
return 0;
case CEPH_CRYPTO_AES:
return ceph_aes_decrypt(secret->key, secret->len, dst,
dst_len, src, src_len);
default:
return -EINVAL;
}
}
int ceph_decrypt2(struct ceph_crypto_key *secret,
void *dst1, size_t *dst1_len,
void *dst2, size_t *dst2_len,
const void *src, size_t src_len)
{
size_t t;
switch (secret->type) {
case CEPH_CRYPTO_NONE:
if (*dst1_len + *dst2_len < src_len)
return -ERANGE;
t = min(*dst1_len, src_len);
memcpy(dst1, src, t);
*dst1_len = t;
src += t;
src_len -= t;
if (src_len) {
t = min(*dst2_len, src_len);
memcpy(dst2, src, t);
*dst2_len = t;
}
return 0;
case CEPH_CRYPTO_AES:
return ceph_aes_decrypt2(secret->key, secret->len,
dst1, dst1_len, dst2, dst2_len,
src, src_len);
default:
return -EINVAL;
}
}
int ceph_encrypt(struct ceph_crypto_key *secret, void *dst, size_t *dst_len,
const void *src, size_t src_len)
{
switch (secret->type) {
case CEPH_CRYPTO_NONE:
if (*dst_len < src_len)
return -ERANGE;
memcpy(dst, src, src_len);
*dst_len = src_len;
return 0;
case CEPH_CRYPTO_AES:
return ceph_aes_encrypt(secret->key, secret->len, dst,
dst_len, src, src_len);
default:
return -EINVAL;
}
}
int ceph_encrypt2(struct ceph_crypto_key *secret, void *dst, size_t *dst_len,
const void *src1, size_t src1_len,
const void *src2, size_t src2_len)
{
switch (secret->type) {
case CEPH_CRYPTO_NONE:
if (*dst_len < src1_len + src2_len)
return -ERANGE;
memcpy(dst, src1, src1_len);
memcpy(dst + src1_len, src2, src2_len);
*dst_len = src1_len + src2_len;
return 0;
case CEPH_CRYPTO_AES:
return ceph_aes_encrypt2(secret->key, secret->len, dst, dst_len,
src1, src1_len, src2, src2_len);
default:
return -EINVAL;
}
}
static int ceph_key_preparse(struct key_preparsed_payload *prep)
{
struct ceph_crypto_key *ckey;
size_t datalen = prep->datalen;
int ret;
void *p;
ret = -EINVAL;
if (datalen <= 0 || datalen > 32767 || !prep->data)
goto err;
ret = -ENOMEM;
ckey = kmalloc(sizeof(*ckey), GFP_KERNEL);
if (!ckey)
goto err;
/* TODO ceph_crypto_key_decode should really take const input */
p = (void *)prep->data;
ret = ceph_crypto_key_decode(ckey, &p, (char*)prep->data+datalen);
if (ret < 0)
goto err_ckey;
prep->payload[0] = ckey;
prep->quotalen = datalen;
return 0;
err_ckey:
kfree(ckey);
err:
return ret;
}
static void ceph_key_free_preparse(struct key_preparsed_payload *prep)
{
struct ceph_crypto_key *ckey = prep->payload[0];
ceph_crypto_key_destroy(ckey);
kfree(ckey);
}
static void ceph_key_destroy(struct key *key)
{
struct ceph_crypto_key *ckey = key->payload.data;
ceph_crypto_key_destroy(ckey);
kfree(ckey);
}
struct key_type key_type_ceph = {
.name = "ceph",
.preparse = ceph_key_preparse,
.free_preparse = ceph_key_free_preparse,
.instantiate = generic_key_instantiate,
.destroy = ceph_key_destroy,
};
int ceph_crypto_init(void) {
return register_key_type(&key_type_ceph);
}
void ceph_crypto_shutdown(void) {
unregister_key_type(&key_type_ceph);
}