Re: GPF in lrw_crypt
On Thu, Dec 17, 2015 at 01:59:11PM +0100, Dmitry Vyukov wrote:
>
> The following program causes GPF in lrw_crypt:
OK, this is a result of certain implementations (such as lrw)
not coping with there being no key gracefully.
I think the easiest way is probably to check this in algif_skcipher.
---8<---
Subject: crypto: algif_skcipher - Require setkey before accept(2)
Some cipher implementations will crash if you try to use them
without calling setkey first. This patch adds a check so that
the accept(2) call will fail with -ENOKEY if setkey hasn't been
done on the socket yet.
Cc: sta...@vger.kernel.org
Reported-by: Dmitry Vyukov <dvyu...@google.com>
Signed-off-by: Herbert Xu <herb...@gondor.apana.org.au>
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index 5c756b3..b62c973 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -31,6 +31,11 @@ struct skcipher_sg_list {
struct scatterlist sg[0];
};
+struct skcipher_tfm {
+ struct crypto_skcipher *skcipher;
+ bool has_key;
+};
+
struct skcipher_ctx {
struct list_head tsgl;
struct af_alg_sgl rsgl;
@@ -750,17 +755,38 @@ static struct proto_ops algif_skcipher_ops = {
static void *skcipher_bind(const char *name, u32 type, u32 mask)
{
- return crypto_alloc_skcipher(name, type, mask);
+ struct skcipher_tfm *tfm;
+
+ tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
+ if (!tfm)
+ return ERR_PTR(-ENOMEM);
+
+ tfm->skcipher = crypto_alloc_skcipher(name, type, mask);
+ if (IS_ERR(tfm->skcipher)) {
+ kfree(tfm);
+ return ERR_CAST(tfm->skcipher);
+ }
+
+ return tfm;
}
static void skcipher_release(void *private)
{
- crypto_free_skcipher(private);
+ struct skcipher_tfm *tfm = private;
+
+ crypto_free_skcipher(tfm->skcipher);
+ kfree(tfm);
}
static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen)
{
- return crypto_skcipher_setkey(private, key, keylen);
+ struct skcipher_tfm *tfm = private;
+ int err;
+
+ err = crypto_skcipher_setkey(tfm->skcipher, key, keylen);
+ tfm->has_key = !err;
+
+ return err;
}
static void skcipher_wait(struct sock *sk)
@@ -792,20 +818,25 @@ static int skcipher_accept_parent(void *private, struct
sock *sk)
{
struct skcipher_ctx *ctx;
struct alg_sock *ask = alg_sk(sk);
- unsigned int len = sizeof(*ctx) + crypto_skcipher_reqsize(private);
+ struct skcipher_tfm *tfm = private;
+ struct crypto_skcipher *skcipher = tfm->skcipher;
+ unsigned int len = sizeof(*ctx) + crypto_skcipher_reqsize(skcipher);
+
+ if (!tfm->has_key)
+ return -ENOKEY;
ctx = sock_kmalloc(sk, len, GFP_KERNEL);
if (!ctx)
return -ENOMEM;
- ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(private),
+ ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(skcipher),
GFP_KERNEL);
if (!ctx->iv) {
sock_kfree_s(sk, ctx, len);
return -ENOMEM;
}
- memset(ctx->iv, 0, crypto_skcipher_ivsize(private));
+ memset(ctx->iv, 0, crypto_skcipher_ivsize(skcipher));
INIT_LIST_HEAD(>tsgl);
ctx->len = len;
@@ -818,7 +849,7 @@ static int skcipher_accept_parent(void *private, struct
sock *sk)
ask->private = ctx;
- skcipher_request_set_tfm(>req, private);
+ skcipher_request_set_tfm(>req, skcipher);
skcipher_request_set_callback(>req, CRYPTO_TFM_REQ_MAY_BACKLOG,
af_alg_complete, >completion);
--
Email: Herbert Xu <herb...@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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Re: GPF in lrw_crypt
On Thu, Dec 24, 2015 at 10:39 AM, Herbert Xu
<herb...@gondor.apana.org.au> wrote:
> On Thu, Dec 17, 2015 at 01:59:11PM +0100, Dmitry Vyukov wrote:
>>
>> The following program causes GPF in lrw_crypt:
>
> OK, this is a result of certain implementations (such as lrw)
> not coping with there being no key gracefully.
>
> I think the easiest way is probably to check this in algif_skcipher.
>
> ---8<---
> Subject: crypto: algif_skcipher - Require setkey before accept(2)
>
> Some cipher implementations will crash if you try to use them
> without calling setkey first. This patch adds a check so that
> the accept(2) call will fail with -ENOKEY if setkey hasn't been
> done on the socket yet.
>
> Cc: sta...@vger.kernel.org
> Reported-by: Dmitry Vyukov <dvyu...@google.com>
> Signed-off-by: Herbert Xu <herb...@gondor.apana.org.au>
>
> diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
> index 5c756b3..b62c973 100644
> --- a/crypto/algif_skcipher.c
> +++ b/crypto/algif_skcipher.c
> @@ -31,6 +31,11 @@ struct skcipher_sg_list {
> struct scatterlist sg[0];
> };
>
> +struct skcipher_tfm {
> + struct crypto_skcipher *skcipher;
> + bool has_key;
> +};
> +
> struct skcipher_ctx {
> struct list_head tsgl;
> struct af_alg_sgl rsgl;
> @@ -750,17 +755,38 @@ static struct proto_ops algif_skcipher_ops = {
>
> static void *skcipher_bind(const char *name, u32 type, u32 mask)
> {
> - return crypto_alloc_skcipher(name, type, mask);
> + struct skcipher_tfm *tfm;
> +
> + tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
> + if (!tfm)
> + return ERR_PTR(-ENOMEM);
> +
> + tfm->skcipher = crypto_alloc_skcipher(name, type, mask);
> + if (IS_ERR(tfm->skcipher)) {
> + kfree(tfm);
> + return ERR_CAST(tfm->skcipher);
> + }
> +
> + return tfm;
> }
>
> static void skcipher_release(void *private)
> {
> - crypto_free_skcipher(private);
> + struct skcipher_tfm *tfm = private;
> +
> + crypto_free_skcipher(tfm->skcipher);
> + kfree(tfm);
> }
>
> static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen)
> {
> - return crypto_skcipher_setkey(private, key, keylen);
> + struct skcipher_tfm *tfm = private;
> + int err;
> +
> + err = crypto_skcipher_setkey(tfm->skcipher, key, keylen);
> + tfm->has_key = !err;
> +
> + return err;
> }
>
> static void skcipher_wait(struct sock *sk)
> @@ -792,20 +818,25 @@ static int skcipher_accept_parent(void *private, struct
> sock *sk)
> {
> struct skcipher_ctx *ctx;
> struct alg_sock *ask = alg_sk(sk);
> - unsigned int len = sizeof(*ctx) + crypto_skcipher_reqsize(private);
> + struct skcipher_tfm *tfm = private;
> + struct crypto_skcipher *skcipher = tfm->skcipher;
> + unsigned int len = sizeof(*ctx) + crypto_skcipher_reqsize(skcipher);
> +
> + if (!tfm->has_key)
> + return -ENOKEY;
>
> ctx = sock_kmalloc(sk, len, GFP_KERNEL);
> if (!ctx)
> return -ENOMEM;
>
> - ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(private),
> + ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(skcipher),
>GFP_KERNEL);
> if (!ctx->iv) {
> sock_kfree_s(sk, ctx, len);
> return -ENOMEM;
> }
>
> - memset(ctx->iv, 0, crypto_skcipher_ivsize(private));
> + memset(ctx->iv, 0, crypto_skcipher_ivsize(skcipher));
>
> INIT_LIST_HEAD(>tsgl);
> ctx->len = len;
> @@ -818,7 +849,7 @@ static int skcipher_accept_parent(void *private, struct
> sock *sk)
>
> ask->private = ctx;
>
> - skcipher_request_set_tfm(>req, private);
> + skcipher_request_set_tfm(>req, skcipher);
> skcipher_request_set_callback(>req, CRYPTO_TFM_REQ_MAY_BACKLOG,
> af_alg_complete, >completion);
>
Hi Herbert,
I am testing with your two patches:
crypto: algif_skcipher - Use new skcipher interface
crypto: algif_skcipher - Require setkey before accept(2)
on top of a88164345b81292b55a8d4829fdd35c8d611cd7d (Dec 23).
Now the following program causes a bunch of use-after-frees and them
kills kernel:
// autogenerated by syzkaller (http://github.com/google/syzkaller)
#include
#include
#include
#include
#include
long r[10];
int main()
{
memset(r, -1, sizeof(r));
r[0] = syscall(SYS_mmap, 0x2000ul, 0xca7000ul, 0x3ul,
0x32ul, 0xu
Re: GPF in lrw_crypt
Am Donnerstag, 17. Dezember 2015, 13:59:11 schrieb Dmitry Vyukov:
Hi Dmitry,
> Hello,
>
> The following program causes GPF in lrw_crypt:
Here we are: this problem looks very much like the error reprt about a GFP in
gf128mul_64_bbe.
>
> // autogenerated by syzkaller (http://github.com/google/syzkaller)
> #include
> #include
> #include
>
> int main()
> {
> long r0 = syscall(SYS_socket, 0x26ul, 0x5ul, 0x0ul, 0, 0, 0);
> long r1 = syscall(SYS_mmap, 0x2000ul, 0x1ul, 0x2ul,
> 0x32ul, 0xul, 0x0ul);
> *(uint16_t*)0x20001000 = 0x26;
> memcpy((void*)0x20001002,
> "\x73\x6b\x63\x69\x70\x68\x65\x72\x00\x00\x00\x00\x00\x00", 14);
> *(uint32_t*)0x20001010 = 0xf;
> *(uint32_t*)0x20001014 = 0x100;
> memcpy((void*)0x20001018,
> "\x6c\x72\x77\x28\x74\x77\x6f\x66\x69\x73\x68\x29\x00\x00\x00\x00\x00\x00\x0
> 0\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x0
> 0\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x0
> 0\x00\x00\x00\x00\x00\x00\x00", 64);
> long r7 = syscall(SYS_bind, r0, 0x20001000ul, 0x58ul, 0, 0, 0);
> long r8 = syscall(SYS_accept4, r0, 0x0ul, 0x200023fdul, 0x800ul, 0,
> 0); memcpy((void*)0x20002fd8,
> "\x09\xf1\x98\x36\x3f\x7d\x29\x96\x55\xe6\xa2\x42\x45\x67\x8f\x7c\x27\x44\x5
> 1\x6f\xbe\x4d\x52\x6f\x40\xaf\xe0\xd6\x04\x8d\x86\x36\x08\xc8\x55\xb8\xfe\x6
> e\x89\xef\x15\x2d\x07\x9a\x74\xab\xc7\x47\x26\xb5\x00\x93\x3b\x59\xe2\x1f\x6
> a\x29\x76\x7f\x9d\x3a\x86\x38\xda\x3e\xfb\xbe\x63\x2e\x38\x2f\x5c\x1c\x4d\xb
> 8\x53\xf9\x97\xdb\x4a\xcc\xad\x55\xb3\xb5\xa0\xb4\xad\xfb\x39\xe5\x44\x12\x0
> b\x5f\x03\xbf\xc7\x28\x36\x1a\x7b\x4a\xff\x3e\x71\x17\x44\xf3\x09\xfb\x44\x4
> 1\x55\x1b\x6e\x6c\xcd\x03\x39\x66\xe2\x87\x65\xdd\x66\x7c\x00\x9f\x46\x54\x6
> 6\xf1\xa8\x4b\xd9\x10\xdc\x45\xd0\x57\x5c\x5e\x97\x42\x3a\xc9\x26\x5a\x55\x5
> 7\x65\x5f\x38\x54\xdd\x1e\xd8\x89\xe0\x34\xf0\x9e\x65\xf8\x89\x8e\xe4\x02\xd
> c\xa2\xa8\x45\x9c\xe9\xca\xef\xad\xdc\x74\xb5", 182);
> long r10 = syscall(SYS_write, r8, 0x20002fd8ul, 0xb6ul, 0, 0, 0);
> *(uint64_t*)0x2fb8 = 0x20004fff;
> *(uint64_t*)0x2fc0 = 0x94;
> *(uint64_t*)0x2fc8 = 0x2000;
> *(uint64_t*)0x2fd0 = 0x5d;
> *(uint64_t*)0x2fd8 = 0x2f1b;
> *(uint64_t*)0x2fe0 = 0xe5;
> *(uint64_t*)0x2fe8 = 0x20004b08;
> *(uint64_t*)0x2ff0 = 0xe9;
> *(uint64_t*)0x2ff8 = 0x20002000;
> *(uint64_t*)0x20001000 = 0x1000;
> long r21 = syscall(SYS_readv, r8, 0x2fb8ul, 0x5ul, 0, 0, 0);
> return 0;
> }
>
>
>
> kasan: CONFIG_KASAN_INLINE enabled
> kasan: GPF could be caused by NULL-ptr deref or user memory
> accessgeneral protection fault: [#1] SMP KASAN
> Modules linked in:
> CPU: 2 PID: 6912 Comm: a.out Not tainted 4.4.0-rc3+ #151
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
> task: 88005ee61680 ti: 88005fef task.ti: 88005fef RIP:
> 0010:[] [] gf128mul_64k_bbe+0x89/0x3f0
> RSP: 0018:88005fef7590 EFLAGS: 00010246
> RAX: dc00 RBX: 0001 RCX:
> RDX: ed000bfdee9f RSI: 88005ee61e40 RDI: ed000bfdeeab
> RBP: 88005fef7650 R08: 0001 R09:
> R10: R11: R12: 88005fef7870
> R13: R14: R15: 11000bfdeeb8
> FS: 026a3880(0063) GS:88006ce0() knlGS:
> CS: 0010 DS: ES: CR0: 8005003b
> CR2: 2fb8 CR3: 5ffa CR4: 06e0
> Stack:
> 88005fef7730 88000fff 11000bfdeeb8 88005fef7870
> 88005fef7710 41b58ab3 87ab3a79
> 82bf9580 82bafa9b 88005ee61680 0001
> Call Trace:
> [] lrw_crypt+0x29d/0xd20 crypto/lrw.c:248
> [] lrw_decrypt+0xf2/0x150
> arch/x86/crypto/serpent_avx2_glue.c:270
> [] async_decrypt+0x1c1/0x2c0 crypto/blkcipher.c:443
> [< inline >] crypto_ablkcipher_decrypt include/linux/crypto.h:921
> [< inline >] skcipher_recvmsg_sync crypto/algif_skcipher.c:676
> [] skcipher_recvmsg+0x1029/0x1f10
> crypto/algif_skcipher.c:706 [< inline >] sock_recvmsg_nosec
> net/socket.c:712
> [] sock_recvmsg+0xaa/0xe0 net/socket.c:720
> [] sock_read_iter+0x273/0x3d0 net/socket.c:797
> [] do_iter_readv_writev+0x14e/0x2c0 fs/read_write.c:664
> [] do_readv_writev+0x2e2/0x880 fs/read_write.c:808
> [] vfs_readv+0x95/0xd0
GPF in lrw_crypt
Hello,
The following program causes GPF in lrw_crypt:
// autogenerated by syzkaller (http://github.com/google/syzkaller)
#include
#include
#include
int main()
{
long r0 = syscall(SYS_socket, 0x26ul, 0x5ul, 0x0ul, 0, 0, 0);
long r1 = syscall(SYS_mmap, 0x2000ul, 0x1ul, 0x2ul,
0x32ul, 0xul, 0x0ul);
*(uint16_t*)0x20001000 = 0x26;
memcpy((void*)0x20001002,
"\x73\x6b\x63\x69\x70\x68\x65\x72\x00\x00\x00\x00\x00\x00", 14);
*(uint32_t*)0x20001010 = 0xf;
*(uint32_t*)0x20001014 = 0x100;
memcpy((void*)0x20001018,
"\x6c\x72\x77\x28\x74\x77\x6f\x66\x69\x73\x68\x29\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
64);
long r7 = syscall(SYS_bind, r0, 0x20001000ul, 0x58ul, 0, 0, 0);
long r8 = syscall(SYS_accept4, r0, 0x0ul, 0x200023fdul, 0x800ul, 0, 0);
memcpy((void*)0x20002fd8,
"\x09\xf1\x98\x36\x3f\x7d\x29\x96\x55\xe6\xa2\x42\x45\x67\x8f\x7c\x27\x44\x51\x6f\xbe\x4d\x52\x6f\x40\xaf\xe0\xd6\x04\x8d\x86\x36\x08\xc8\x55\xb8\xfe\x6e\x89\xef\x15\x2d\x07\x9a\x74\xab\xc7\x47\x26\xb5\x00\x93\x3b\x59\xe2\x1f\x6a\x29\x76\x7f\x9d\x3a\x86\x38\xda\x3e\xfb\xbe\x63\x2e\x38\x2f\x5c\x1c\x4d\xb8\x53\xf9\x97\xdb\x4a\xcc\xad\x55\xb3\xb5\xa0\xb4\xad\xfb\x39\xe5\x44\x12\x0b\x5f\x03\xbf\xc7\x28\x36\x1a\x7b\x4a\xff\x3e\x71\x17\x44\xf3\x09\xfb\x44\x41\x55\x1b\x6e\x6c\xcd\x03\x39\x66\xe2\x87\x65\xdd\x66\x7c\x00\x9f\x46\x54\x66\xf1\xa8\x4b\xd9\x10\xdc\x45\xd0\x57\x5c\x5e\x97\x42\x3a\xc9\x26\x5a\x55\x57\x65\x5f\x38\x54\xdd\x1e\xd8\x89\xe0\x34\xf0\x9e\x65\xf8\x89\x8e\xe4\x02\xdc\xa2\xa8\x45\x9c\xe9\xca\xef\xad\xdc\x74\xb5",
182);
long r10 = syscall(SYS_write, r8, 0x20002fd8ul, 0xb6ul, 0, 0, 0);
*(uint64_t*)0x2fb8 = 0x20004fff;
*(uint64_t*)0x2fc0 = 0x94;
*(uint64_t*)0x2fc8 = 0x2000;
*(uint64_t*)0x2fd0 = 0x5d;
*(uint64_t*)0x2fd8 = 0x2f1b;
*(uint64_t*)0x2fe0 = 0xe5;
*(uint64_t*)0x2fe8 = 0x20004b08;
*(uint64_t*)0x2ff0 = 0xe9;
*(uint64_t*)0x2ff8 = 0x20002000;
*(uint64_t*)0x20001000 = 0x1000;
long r21 = syscall(SYS_readv, r8, 0x2fb8ul, 0x5ul, 0, 0, 0);
return 0;
}
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory
accessgeneral protection fault: [#1] SMP KASAN
Modules linked in:
CPU: 2 PID: 6912 Comm: a.out Not tainted 4.4.0-rc3+ #151
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: 88005ee61680 ti: 88005fef task.ti: 88005fef
RIP: 0010:[] [] gf128mul_64k_bbe+0x89/0x3f0
RSP: 0018:88005fef7590 EFLAGS: 00010246
RAX: dc00 RBX: 0001 RCX:
RDX: ed000bfdee9f RSI: 88005ee61e40 RDI: ed000bfdeeab
RBP: 88005fef7650 R08: 0001 R09:
R10: R11: R12: 88005fef7870
R13: R14: R15: 11000bfdeeb8
FS: 026a3880(0063) GS:88006ce0() knlGS:
CS: 0010 DS: ES: CR0: 8005003b
CR2: 2fb8 CR3: 5ffa CR4: 06e0
Stack:
88005fef7730 88000fff 11000bfdeeb8 88005fef7870
88005fef7710 41b58ab3 87ab3a79
82bf9580 82bafa9b 88005ee61680 0001
Call Trace:
[] lrw_crypt+0x29d/0xd20 crypto/lrw.c:248
[] lrw_decrypt+0xf2/0x150
arch/x86/crypto/serpent_avx2_glue.c:270
[] async_decrypt+0x1c1/0x2c0 crypto/blkcipher.c:443
[< inline >] crypto_ablkcipher_decrypt include/linux/crypto.h:921
[< inline >] skcipher_recvmsg_sync crypto/algif_skcipher.c:676
[] skcipher_recvmsg+0x1029/0x1f10 crypto/algif_skcipher.c:706
[< inline >] sock_recvmsg_nosec net/socket.c:712
[] sock_recvmsg+0xaa/0xe0 net/socket.c:720
[] sock_read_iter+0x273/0x3d0 net/socket.c:797
[] do_iter_readv_writev+0x14e/0x2c0 fs/read_write.c:664
[] do_readv_writev+0x2e2/0x880 fs/read_write.c:808
[] vfs_readv+0x95/0xd0 fs/read_write.c:834
[< inline >] SYSC_readv fs/read_write.c:860
[] SyS_readv+0x111/0x2f0 fs/read_write.c:852
[] entry_SYSCALL_64_fastpath+0x16/0x7a
arch/x86/entry/entry_64.S:185
Code: 04 00 00 f4 f4 c7 40 08 f3 f3 f3 f3 e8 d1 e9 a0 fe 4d 85 f6 0f
84 f6 01 00 00 4c 89 f1 48 b8 00 00 00 00 00 fc ff df 48 c1 e9 03 <80>
3c 01 00 0f 85 48 03 00 00 48 8b 5c 24 18 4d 8b 26 48 83 c3
RIP [] gf128mul_64k_bbe+0x89/0x3f0 crypto/gf128mul.c:379
RSP
---[ end trace 018c54843b88ec1d ]---
On upstream commit 31ade3b83e1821da5fbb2f11b5b3d4ab2ec39db8 (Nov 29).
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