Merge tag 'dm-3.17-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mappe...

Pull device mapper fix from Mike Snitzer:
 "Fix a 3.17-rc1 regression introduced by switching the DM crypt target
  to using per-bio data"

* tag 'dm-3.17-fix' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm crypt: fix access beyond the end of allocated space

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index 2785007..cd15e08 100644 (file)
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1688,6 +1688,7 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
        unsigned int key_size, opt_params;
        unsigned long long tmpll;
        int ret;
+       size_t iv_size_padding;
        struct dm_arg_set as;
        const char *opt_string;
        char dummy;
@@ -1724,20 +1725,32 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv)
 
        cc->dmreq_start = sizeof(struct ablkcipher_request);
        cc->dmreq_start += crypto_ablkcipher_reqsize(any_tfm(cc));
-       cc->dmreq_start = ALIGN(cc->dmreq_start, crypto_tfm_ctx_alignment());
-       cc->dmreq_start += crypto_ablkcipher_alignmask(any_tfm(cc)) &
-                          ~(crypto_tfm_ctx_alignment() - 1);
+       cc->dmreq_start = ALIGN(cc->dmreq_start, __alignof__(struct dm_crypt_request));
+
+       if (crypto_ablkcipher_alignmask(any_tfm(cc)) < CRYPTO_MINALIGN) {
+               /* Allocate the padding exactly */
+               iv_size_padding = -(cc->dmreq_start + sizeof(struct dm_crypt_request))
+                               & crypto_ablkcipher_alignmask(any_tfm(cc));
+       } else {
+               /*
+                * If the cipher requires greater alignment than kmalloc
+                * alignment, we don't know the exact position of the
+                * initialization vector. We must assume worst case.
+                */
+               iv_size_padding = crypto_ablkcipher_alignmask(any_tfm(cc));
+       }
 
        cc->req_pool = mempool_create_kmalloc_pool(MIN_IOS, cc->dmreq_start +
-                       sizeof(struct dm_crypt_request) + cc->iv_size);
+                       sizeof(struct dm_crypt_request) + iv_size_padding + cc->iv_size);
        if (!cc->req_pool) {
                ti->error = "Cannot allocate crypt request mempool";
                goto bad;
        }
 
        cc->per_bio_data_size = ti->per_bio_data_size =
-                               sizeof(struct dm_crypt_io) + cc->dmreq_start +
-                               sizeof(struct dm_crypt_request) + cc->iv_size;
+               ALIGN(sizeof(struct dm_crypt_io) + cc->dmreq_start +
+                     sizeof(struct dm_crypt_request) + iv_size_padding + cc->iv_size,
+                     ARCH_KMALLOC_MINALIGN);
 
        cc->page_pool = mempool_create_page_pool(MIN_POOL_PAGES, 0);
        if (!cc->page_pool) {