dm crypt: fix free of bad values after tfm allocation failure

commit 5d0be84ec0cacfc7a6d6ea548afdd07d481324cd upstream.

If crypt_alloc_tfms() had to allocate multiple tfms and it failed before
the last allocation, then it would call crypt_free_tfms() and could free
pointers from uninitialized memory -- due to the crypt_free_tfms() check
for non-zero cc->tfms[i].  Fix by allocating zeroed memory.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c
index f87223056696be3c13cd5a14587ca3368d79de3c..34e7db1e73041c3d2172cd70bcfe25034575ae34 100644 (file)
--- a/drivers/md/dm-crypt.c
+++ b/drivers/md/dm-crypt.c
@@ -1400,7 +1400,7 @@ static int crypt_alloc_tfms(struct crypt_config *cc, char *ciphermode)
        unsigned i;
        int err;
 
-       cc->tfms = kmalloc(cc->tfms_count * sizeof(struct crypto_ablkcipher *),
+       cc->tfms = kzalloc(cc->tfms_count * sizeof(struct crypto_ablkcipher *),
                           GFP_KERNEL);
        if (!cc->tfms)
                return -ENOMEM;