crypto/algif_skcipher.c | 10 +++++++--- crypto/skcipher.c | 1 - include/crypto/internal/skcipher.h | 1 + 3 files changed, 8 insertions(+), 4 deletions(-)
The space allocated to areq is not sufficient to access the member __ctx of
struct skcipher_request, as the space occupied by struct arc4_ctx for reading
is 1032 bytes, while the requested memory size in skcipher_recvmsg() is:
sizeof(struct af_alg_async_req) + crypto_skcipher_reqsize(tfm) = 736 bytes,
which does not include the memory required for __ctx of struct skcipher_request.
Reported-by: syzbot+8ffb0839a24e9c6bfa76@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
---
crypto/algif_skcipher.c | 10 +++++++---
crypto/skcipher.c | 1 -
include/crypto/internal/skcipher.h | 1 +
3 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 02cea2149504..b69d361b5515 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -33,6 +33,7 @@
#include <linux/module.h>
#include <linux/net.h>
#include <net/sock.h>
+#include <crypto/internal/skcipher.h>
static int skcipher_sendmsg(struct socket *sock, struct msghdr *msg,
size_t size)
@@ -102,11 +103,12 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
struct alg_sock *pask = alg_sk(psk);
struct af_alg_ctx *ctx = ask->private;
struct crypto_skcipher *tfm = pask->private;
+ struct skcipher_alg *alg = crypto_skcipher_alg(tfm);
unsigned int bs = crypto_skcipher_chunksize(tfm);
struct af_alg_async_req *areq;
unsigned cflags = 0;
int err = 0;
- size_t len = 0;
+ size_t len = 0, aqlen;
if (!ctx->init || (ctx->more && ctx->used < bs)) {
err = af_alg_wait_for_data(sk, flags, bs);
@@ -115,8 +117,10 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg,
}
/* Allocate cipher request for current operation. */
- areq = af_alg_alloc_areq(sk, sizeof(struct af_alg_async_req) +
- crypto_skcipher_reqsize(tfm));
+ aqlen = sizeof(struct af_alg_async_req) + crypto_skcipher_reqsize(tfm);
+ if (alg->co.base.cra_type != &crypto_skcipher_type)
+ aqlen += 1032;
+ areq = af_alg_alloc_areq(sk, aqlen);
if (IS_ERR(areq))
return PTR_ERR(areq);
diff --git a/crypto/skcipher.c b/crypto/skcipher.c
index bc70e159d27d..0ae4a05a5aa7 100644
--- a/crypto/skcipher.c
+++ b/crypto/skcipher.c
@@ -44,7 +44,6 @@ struct skcipher_walk_buffer {
u8 buffer[];
};
-static const struct crypto_type crypto_skcipher_type;
static int skcipher_walk_next(struct skcipher_walk *walk);
diff --git a/include/crypto/internal/skcipher.h b/include/crypto/internal/skcipher.h
index 7ae42afdcf3e..3c05872652f2 100644
--- a/include/crypto/internal/skcipher.h
+++ b/include/crypto/internal/skcipher.h
@@ -24,6 +24,7 @@
struct aead_request;
struct rtattr;
+static const struct crypto_type crypto_skcipher_type;
struct skcipher_instance {
void (*free)(struct skcipher_instance *inst);
--
2.43.0Hi Edward,
kernel test robot noticed the following build warnings:
[auto build test WARNING on next-20231222]
url: https://github.com/intel-lab-lkp/linux/commits/Edward-Adam-Davis/crypto-fix-oob-Read-in-arc4_crypt/20231222-172845
base: next-20231222
patch link: https://lore.kernel.org/r/tencent_656D589558EA3EED8ACF3C79166F202E010A%40qq.com
patch subject: [PATCH next] crypto: fix oob Read in arc4_crypt
config: i386-buildonly-randconfig-003-20231224 (https://download.01.org/0day-ci/archive/20231225/202312250259.yyBgM27K-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231225/202312250259.yyBgM27K-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202312250259.yyBgM27K-lkp@intel.com/
All warnings (new ones prefixed by >>):
In file included from drivers/crypto/padlock-aes.c:13:
>> include/crypto/internal/skcipher.h:27:33: warning: 'crypto_skcipher_type' defined but not used [-Wunused-const-variable=]
27 | static const struct crypto_type crypto_skcipher_type;
| ^~~~~~~~~~~~~~~~~~~~
vim +/crypto_skcipher_type +27 include/crypto/internal/skcipher.h
24
25 struct aead_request;
26 struct rtattr;
> 27 static const struct crypto_type crypto_skcipher_type;
28
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
On Wed, Dec 20, 2023 at 11:53:55PM +0800, Edward Adam Davis wrote: > The space allocated to areq is not sufficient to access the member __ctx of > struct skcipher_request, as the space occupied by struct arc4_ctx for reading > is 1032 bytes, while the requested memory size in skcipher_recvmsg() is: > sizeof(struct af_alg_async_req) + crypto_skcipher_reqsize(tfm) = 736 bytes, > which does not include the memory required for __ctx of struct skcipher_request. > > Reported-by: syzbot+8ffb0839a24e9c6bfa76@syzkaller.appspotmail.com > Signed-off-by: Edward Adam Davis <eadavis@qq.com> > --- > crypto/algif_skcipher.c | 10 +++++++--- > crypto/skcipher.c | 1 - > include/crypto/internal/skcipher.h | 1 + > 3 files changed, 8 insertions(+), 4 deletions(-) I see where the real bug is. The statesize is not being passed along by ecb so that's why we end up with no memory. Cheers, -- Email: Herbert Xu <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
On Wed, Dec 20, 2023 at 11:53:55PM +0800, Edward Adam Davis wrote: > The space allocated to areq is not sufficient to access the member __ctx of > struct skcipher_request, as the space occupied by struct arc4_ctx for reading > is 1032 bytes, while the requested memory size in skcipher_recvmsg() is: > sizeof(struct af_alg_async_req) + crypto_skcipher_reqsize(tfm) = 736 bytes, > which does not include the memory required for __ctx of struct skcipher_request. I cannot reproduce this. The total allocated size I get is 1768. How can crypto_skcipher_reqsize(tfm) return zero? Thanks, -- Email: Herbert Xu <herbert@gondor.apana.org.au> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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