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From 7156c794b8ab462705e6ac80c5fa69565eb44c62 Mon Sep 17 00:00:00 2001
From: Eric Biggers <ebiggers@google.com>
Date: Wed, 20 Dec 2017 14:28:25 -0800
Subject: [PATCH] crypto: pcrypt - fix freeing pcrypt instances
commit d76c68109f37cb85b243a1cf0f40313afd2bae68 upstream.
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.
CVE: CVE-2017-18075
Upstream-Status: Backport [https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?h=linux-4.14.y&id=7156c794b8ab462705e6ac80c5fa69565eb44c62]
Reported-by: syzbot <syzkaller@googlegroups.com>
Fixes: 0496f56065e0 ("crypto: pcrypt - Add support for new AEAD interface")
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andreas Wellving <andreas.wellving@enea.com>
---
crypto/pcrypt.c | 19 ++++++++++---------
1 file changed, 10 insertions(+), 9 deletions(-)
diff --git a/crypto/pcrypt.c b/crypto/pcrypt.c
index ee9cfb99fe25..f8ec3d4ba4a8 100644
--- a/crypto/pcrypt.c
+++ b/crypto/pcrypt.c
@@ -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,
};
--
2.20.1
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