On Fri, Aug 19, 2016 at 03:21:24PM -0400, Sowmini Varadhan wrote:
>
> Hi Herbert,
>
> In the process of testing ipsec I ran into panics (details below)
> with the algorithm
> "aead rfc4106(gcm(aes)) 0x1234567890123456789012345678901234567890 64"
>
> git-bisect analyzed this down to
>
> 7271b33cb87e80f3a416fb031ad3ca87f0bea80a is the first bad commit
> commit 7271b33cb87e80f3a416fb031ad3ca87f0bea80a
> Author: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
> Date: Tue Jun 21 16:55:16 2016 +0800
>
> crypto: ghash-clmulni - Fix cryptd reordering
This bisection doesn't make much sense as this patch just causes
cryptd to be used a little more more frequently. But it does
point the finger at cryptd.
> [ 124.627594] BUG: unable to handle kernel paging request at 00000001000000c5
> [ 124.627612] ------------[ cut here ]------------
> [ 124.627620] WARNING: CPU: 3 PID: 0 at lib/list_debug.c:62 __list_del_entry+0x
> 86/0xd0
> [ 124.627621] list_del corruption. next->prev should be ffff88085cebd168, but w
> as 00000000ffffff8d
> [ 124.627622] Modules linked in:
So we have list corruption here, possibly caused by use-after-free.
I did spot one bug in the AEAD cryptd path where we end up using
the wrong tfm to track refcnt.
Does this patch help?
---8<---
Subject: crypto: cryptd - Use correct tfm object for AEAD tracking
The AEAD code path incorrectly uses the child tfm to track the
cryptd refcnt, and then potentially frees the child tfm.
Fixes: 81760ea6a95a ("crypto: cryptd - Add helpers to check...")
Reported-by: Sowmini Varadhan <sowmini.varadhan@xxxxxxxxxx>
Signed-off-by: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
diff --git a/crypto/cryptd.c b/crypto/cryptd.c
index cf8037a..77207b4 100644
--- a/crypto/cryptd.c
+++ b/crypto/cryptd.c
@@ -733,13 +733,14 @@ static void cryptd_aead_crypt(struct aead_request *req,
rctx = aead_request_ctx(req);
compl = rctx->complete;
+ tfm = crypto_aead_reqtfm(req);
+
if (unlikely(err == -EINPROGRESS))
goto out;
aead_request_set_tfm(req, child);
err = crypt( req );
out:
- tfm = crypto_aead_reqtfm(req);
ctx = crypto_aead_ctx(tfm);
refcnt = atomic_read(&ctx->refcnt);
--
Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
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