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crypto: pcrypt - fix freeing pcrypt instances

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pcrypt is using the old way of freeing instances, where the ->free()
method specified in the 'struct crypto_template' is passed a pointer to
the 'struct crypto_instance'.  But the crypto_instance is being
kfree()'d directly, which is incorrect because the memory was actually
allocated as an aead_instance, which contains the crypto_instance at a
nonzero offset.  Thus, the wrong pointer was being kfree()'d.

Fix it by switching to the new way to free aead_instance's where the
->free() method is specified in the aead_instance itself.

Reported-by: syzbot <syzkaller@googlegroups.com>
Fixes: 0496f56065 ("crypto: pcrypt - Add support for new AEAD interface")
Cc: <stable@vger.kernel.org> # v4.2+
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Eric Biggers 2017-12-20 14:28:25 -08:00 committed by Herbert Xu
parent 203f45003a
commit d76c68109f
1 changed files with 10 additions and 9 deletions
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19
crypto/pcrypt.c
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@ -254,6 +254,14 @@ static void pcrypt_aead_exit_tfm(struct crypto_aead *tfm)
crypto_free_aead(ctx->child);
}
static void pcrypt_free(struct aead_instance *inst)
{
struct pcrypt_instance_ctx *ctx = aead_instance_ctx(inst);
crypto_drop_aead(&ctx->spawn);
kfree(inst);
}
static int pcrypt_init_instance(struct crypto_instance *inst,
struct crypto_alg *alg)
{
@ -319,6 +327,8 @@ static int pcrypt_create_aead(struct crypto_template *tmpl, struct rtattr **tb,
inst->alg.encrypt = pcrypt_aead_encrypt;
inst->alg.decrypt = pcrypt_aead_decrypt;
inst->free = pcrypt_free;
err = aead_register_instance(tmpl, inst);
if (err)
goto out_drop_aead;
@ -349,14 +359,6 @@ static int pcrypt_create(struct crypto_template *tmpl, struct rtattr **tb)
return -EINVAL;
}
static void pcrypt_free(struct crypto_instance *inst)
{
struct pcrypt_instance_ctx *ctx = crypto_instance_ctx(inst);
crypto_drop_aead(&ctx->spawn);
kfree(inst);
}
static int pcrypt_cpumask_change_notify(struct notifier_block *self,
unsigned long val, void *data)
{
@ -469,7 +471,6 @@ static void pcrypt_fini_padata(struct padata_pcrypt *pcrypt)
static struct crypto_template pcrypt_tmpl = {
.name = "pcrypt",
.create = pcrypt_create,
.free = pcrypt_free,
.module = THIS_MODULE,
};