[PATCH 3.10 19/70] libceph: do not crash on large auth tickets

Greg Kroah-Hartman
2014-11-19T21:36:28Z

From: Ilya Dryomov <idryomov@redhat.com>

commit aaef31703a0cf6a733e651885bfb49edc3ac6774 upstream.

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.

Signed-off-by: Ilya Dryomov <idryomov@redhat.com>
Reviewed-by: Sage Weil <sage@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
net/ceph/crypto.c | 169 ++++++++++++++++++++++++++++++++++++++++++------------
1 file changed, 132 insertions(+), 37 deletions(-)

--- a/net/ceph/crypto.c
+++ b/net/ceph/crypto.c
@@ -89,11 +89,82 @@ static struct crypto_blkcipher *ceph_cry

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], sg_out[1];
+ 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;
@@ -109,16 +180,18 @@ static int ceph_aes_encrypt(const void *

*dst_len = src_len + zero_padding;

- crypto_blkcipher_setkey((void *)tfm, key, key_len);
sg_init_table(sg_in, 2);
sg_set_buf(&sg_in[0], src, src_len);
sg_set_buf(&sg_in[1], pad, zero_padding);
- sg_init_table(sg_out, 1);
- sg_set_buf(sg_out, dst, *dst_len);
+ 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);
@@ -127,16 +200,22 @@ static int ceph_aes_encrypt(const void *
print_hex_dump(KERN_ERR, "enc pad: ", DUMP_PREFIX_NONE, 16, 1,
pad, zero_padding, 1);
*/
- ret = crypto_blkcipher_encrypt(&desc, sg_out, sg_in,
+ ret = crypto_blkcipher_encrypt(&desc, sg_out.sgl, sg_in,
src_len + zero_padding);
- crypto_free_blkcipher(tfm);
- if (ret < 0)
+ 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);
*/
- return 0;
+
+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,
@@ -144,7 +223,8 @@ static int ceph_aes_encrypt2(const void
const void *src1, size_t src1_len,
const void *src2, size_t src2_len)
{
- struct scatterlist sg_in[3], sg_out[1];
+ 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;
@@ -160,17 +240,19 @@ static int ceph_aes_encrypt2(const void

*dst_len = src1_len + src2_len + zero_padding;

- crypto_blkcipher_setkey((void *)tfm, key, key_len);
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);
- sg_init_table(sg_out, 1);
- sg_set_buf(sg_out, dst, *dst_len);
+ 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);
@@ -181,23 +263,30 @@ static int ceph_aes_encrypt2(const void
print_hex_dump(KERN_ERR, "enc pad: ", DUMP_PREFIX_NONE, 16, 1,
pad, zero_padding, 1);
*/
- ret = crypto_blkcipher_encrypt(&desc, sg_out, sg_in,
+ ret = crypto_blkcipher_encrypt(&desc, sg_out.sgl, sg_in,
src1_len + src2_len + zero_padding);
- crypto_free_blkcipher(tfm);
- if (ret < 0)
+ 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);
*/
- return 0;
+
+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 scatterlist sg_in[1], sg_out[2];
+ 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];
@@ -209,16 +298,16 @@ static int ceph_aes_decrypt(const void *
if (IS_ERR(tfm))
return PTR_ERR(tfm);

- crypto_blkcipher_setkey((void *)tfm, key, key_len);
- sg_init_table(sg_in, 1);
sg_init_table(sg_out, 2);
- sg_set_buf(sg_in, src, src_len);
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);

/*
@@ -227,12 +316,10 @@ static int ceph_aes_decrypt(const void *
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, src_len);
- crypto_free_blkcipher(tfm);
+ ret = crypto_blkcipher_decrypt(&desc, sg_out, sg_in.sgl, src_len);
if (ret < 0) {
pr_err("ceph_aes_decrypt failed %d\n", ret);
- return ret;
+ goto out_sg;
}

if (src_len <= *dst_len)
@@ -250,7 +337,12 @@ static int ceph_aes_decrypt(const void *
print_hex_dump(KERN_ERR, "dec out: ", DUMP_PREFIX_NONE, 16, 1,
dst, *dst_len, 1);
*/
- return 0;
+
+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,
@@ -258,7 +350,8 @@ static int ceph_aes_decrypt2(const void
void *dst2, size_t *dst2_len,
const void *src, size_t src_len)
{
- struct scatterlist sg_in[1], sg_out[3];
+ 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];
@@ -270,17 +363,17 @@ static int ceph_aes_decrypt2(const void
if (IS_ERR(tfm))
return PTR_ERR(tfm);

- sg_init_table(sg_in, 1);
- sg_set_buf(sg_in, src, src_len);
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);

/*
@@ -289,12 +382,10 @@ static int ceph_aes_decrypt2(const void
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, src_len);
- crypto_free_blkcipher(tfm);
+ ret = crypto_blkcipher_decrypt(&desc, sg_out, sg_in.sgl, src_len);
if (ret < 0) {
pr_err("ceph_aes_decrypt failed %d\n", ret);
- return ret;
+ goto out_sg;
}

if (src_len <= *dst1_len)
@@ -324,7 +415,11 @@ static int ceph_aes_decrypt2(const void
dst2, *dst2_len, 1);
*/

- return 0;
+out_sg:
+ teardown_sgtable(&sg_in);
+out_tfm:
+ crypto_free_blkcipher(tfm);
+ return ret;
}