2016-04-03 04:37:15

by Herbert Xu

[permalink] [raw]
Subject: [PATCH v2] sunrpc: Fix skcipher/shash conversion

On Sat, Apr 02, 2016 at 11:59:00PM -0400, J. Bruce Fields wrote:
>
> Thanks. It's getting further now, but appears to be freezing later.
> Possibly unrelated. I'm travelling, and it'll be Monday or Wednesday
> till I can take another look.

Thanks for the update. I've found another bug in the hash conversion
that causes memory corruption which may lead to your hang.

Here's a patch with the previous fix plus the new hash fixes.

---8<---
The skcpiher/shash conversion introduced a number of bugs in the
sunrpc code:

1) Missing calls to skcipher_request_set_tfm lead to crashes.
2) The allocation size of shash_desc is too small which leads to
memory corruption.

Fixes: 3b5cf20cf439 ("sunrpc: Use skcipher and ahash/shash")
Reported-by: J. Bruce Fields <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>

diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c
index d94a8e1..da26455 100644
--- a/net/sunrpc/auth_gss/gss_krb5_crypto.c
+++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c
@@ -78,6 +78,7 @@ krb5_encrypt(
memcpy(out, in, length);
sg_init_one(sg, out, length);

+ skcipher_request_set_tfm(req, tfm);
skcipher_request_set_callback(req, 0, NULL, NULL);
skcipher_request_set_crypt(req, sg, sg, length, local_iv);

@@ -115,6 +116,7 @@ krb5_decrypt(
memcpy(out, in, length);
sg_init_one(sg, out, length);

+ skcipher_request_set_tfm(req, tfm);
skcipher_request_set_callback(req, 0, NULL, NULL);
skcipher_request_set_crypt(req, sg, sg, length, local_iv);

@@ -946,7 +948,8 @@ krb5_rc4_setup_seq_key(struct krb5_ctx *kctx, struct crypto_skcipher *cipher,
return PTR_ERR(hmac);
}

- desc = kmalloc(sizeof(*desc), GFP_KERNEL);
+ desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
+ GFP_KERNEL);
if (!desc) {
dprintk("%s: failed to allocate shash descriptor for '%s'\n",
__func__, kctx->gk5e->cksum_name);
@@ -1012,7 +1015,8 @@ krb5_rc4_setup_enc_key(struct krb5_ctx *kctx, struct crypto_skcipher *cipher,
return PTR_ERR(hmac);
}

- desc = kmalloc(sizeof(*desc), GFP_KERNEL);
+ desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
+ GFP_KERNEL);
if (!desc) {
dprintk("%s: failed to allocate shash descriptor for '%s'\n",
__func__, kctx->gk5e->cksum_name);
diff --git a/net/sunrpc/auth_gss/gss_krb5_mech.c b/net/sunrpc/auth_gss/gss_krb5_mech.c
index 71341cc..6542749 100644
--- a/net/sunrpc/auth_gss/gss_krb5_mech.c
+++ b/net/sunrpc/auth_gss/gss_krb5_mech.c
@@ -451,7 +451,8 @@ context_derive_keys_rc4(struct krb5_ctx *ctx)
goto out_err_free_hmac;


- desc = kmalloc(sizeof(*desc), GFP_KERNEL);
+ desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
+ GFP_KERNEL);
if (!desc) {
dprintk("%s: failed to allocate hash descriptor for '%s'\n",
__func__, ctx->gk5e->cksum_name);
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt


2016-04-03 22:15:45

by J. Bruce Fields

[permalink] [raw]
Subject: Re: [PATCH v2] sunrpc: Fix skcipher/shash conversion

On Sun, Apr 03, 2016 at 12:37:15PM +0800, Herbert Xu wrote:
> On Sat, Apr 02, 2016 at 11:59:00PM -0400, J. Bruce Fields wrote:
> >
> > Thanks. It's getting further now, but appears to be freezing later.
> > Possibly unrelated. I'm travelling, and it'll be Monday or Wednesday
> > till I can take another look.
>
> Thanks for the update. I've found another bug in the hash conversion
> that causes memory corruption which may lead to your hang.
>
> Here's a patch with the previous fix plus the new hash fixes.

OK, I did get a chance to run this, and so far it looks good--it got
faszter than the last time, anyway. Thanks!

For some reason, the original didn't appear to get cc'd to the linux-nfs
list. Or did it, and I missed it? I do get lazy sometimes, but in
general something like this I'd at least grab and run some tests on.
Especially if there's a git tree I can grab, then it just takes me a
minute to kick off.

--b.

>
> ---8<---
> The skcpiher/shash conversion introduced a number of bugs in the
> sunrpc code:
>
> 1) Missing calls to skcipher_request_set_tfm lead to crashes.
> 2) The allocation size of shash_desc is too small which leads to
> memory corruption.
>
> Fixes: 3b5cf20cf439 ("sunrpc: Use skcipher and ahash/shash")
> Reported-by: J. Bruce Fields <[email protected]>
> Signed-off-by: Herbert Xu <[email protected]>
>
> diff --git a/net/sunrpc/auth_gss/gss_krb5_crypto.c b/net/sunrpc/auth_gss/gss_krb5_crypto.c
> index d94a8e1..da26455 100644
> --- a/net/sunrpc/auth_gss/gss_krb5_crypto.c
> +++ b/net/sunrpc/auth_gss/gss_krb5_crypto.c
> @@ -78,6 +78,7 @@ krb5_encrypt(
> memcpy(out, in, length);
> sg_init_one(sg, out, length);
>
> + skcipher_request_set_tfm(req, tfm);
> skcipher_request_set_callback(req, 0, NULL, NULL);
> skcipher_request_set_crypt(req, sg, sg, length, local_iv);
>
> @@ -115,6 +116,7 @@ krb5_decrypt(
> memcpy(out, in, length);
> sg_init_one(sg, out, length);
>
> + skcipher_request_set_tfm(req, tfm);
> skcipher_request_set_callback(req, 0, NULL, NULL);
> skcipher_request_set_crypt(req, sg, sg, length, local_iv);
>
> @@ -946,7 +948,8 @@ krb5_rc4_setup_seq_key(struct krb5_ctx *kctx, struct crypto_skcipher *cipher,
> return PTR_ERR(hmac);
> }
>
> - desc = kmalloc(sizeof(*desc), GFP_KERNEL);
> + desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
> + GFP_KERNEL);
> if (!desc) {
> dprintk("%s: failed to allocate shash descriptor for '%s'\n",
> __func__, kctx->gk5e->cksum_name);
> @@ -1012,7 +1015,8 @@ krb5_rc4_setup_enc_key(struct krb5_ctx *kctx, struct crypto_skcipher *cipher,
> return PTR_ERR(hmac);
> }
>
> - desc = kmalloc(sizeof(*desc), GFP_KERNEL);
> + desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
> + GFP_KERNEL);
> if (!desc) {
> dprintk("%s: failed to allocate shash descriptor for '%s'\n",
> __func__, kctx->gk5e->cksum_name);
> diff --git a/net/sunrpc/auth_gss/gss_krb5_mech.c b/net/sunrpc/auth_gss/gss_krb5_mech.c
> index 71341cc..6542749 100644
> --- a/net/sunrpc/auth_gss/gss_krb5_mech.c
> +++ b/net/sunrpc/auth_gss/gss_krb5_mech.c
> @@ -451,7 +451,8 @@ context_derive_keys_rc4(struct krb5_ctx *ctx)
> goto out_err_free_hmac;
>
>
> - desc = kmalloc(sizeof(*desc), GFP_KERNEL);
> + desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
> + GFP_KERNEL);
> if (!desc) {
> dprintk("%s: failed to allocate hash descriptor for '%s'\n",
> __func__, ctx->gk5e->cksum_name);
> --
> Email: Herbert Xu <[email protected]>
> Home Page: http://gondor.apana.org.au/~herbert/
> PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

2016-04-04 01:22:02

by Herbert Xu

[permalink] [raw]
Subject: Re: [PATCH v2] sunrpc: Fix skcipher/shash conversion

On Sun, Apr 03, 2016 at 06:15:43PM -0400, J. Bruce Fields wrote:
>
> OK, I did get a chance to run this, and so far it looks good--it got
> faszter than the last time, anyway. Thanks!

Thanks!

> For some reason, the original didn't appear to get cc'd to the linux-nfs
> list. Or did it, and I missed it? I do get lazy sometimes, but in
> general something like this I'd at least grab and run some tests on.
> Especially if there's a git tree I can grab, then it just takes me a
> minute to kick off.

I'm pretty sure it did get to linux-nfs, or at least the archive :)

https://www.spinics.net/lists/linux-nfs/msg56240.html

Cheers,
--
Email: Herbert Xu <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt

2016-04-04 03:38:34

by J. Bruce Fields

[permalink] [raw]
Subject: Re: [PATCH v2] sunrpc: Fix skcipher/shash conversion

On Mon, Apr 04, 2016 at 09:22:02AM +0800, Herbert Xu wrote:
> On Sun, Apr 03, 2016 at 06:15:43PM -0400, J. Bruce Fields wrote:
> > For some reason, the original didn't appear to get cc'd to the linux-nfs
> > list. Or did it, and I missed it? I do get lazy sometimes, but in
> > general something like this I'd at least grab and run some tests on.
> > Especially if there's a git tree I can grab, then it just takes me a
> > minute to kick off.
>
> I'm pretty sure it did get to linux-nfs, or at least the archive :)
>
> https://www.spinics.net/lists/linux-nfs/msg56240.html

D'oh. I was probably just lame, then. Thanks for the fix. Feel free
to add my tested-by: if you want.

Hm, now I'm seeing list corruption in the rpc code on callbacks....
That's almost certainly unrelated to this, though.

--b.