From: Herbert Xu <herbert@gondor.apana.org.au>
Subject: Re: [PATCH v2] crypto: vmx - Fix sleep-in-atomic bugs
Date: Sat, 25 Aug 2018 21:28:57 +0800
Message-ID: <20180825132857.josnvyeztipef4pv@gondor.apana.org.au>
References: <CAAUqJDt_y04ts7Aq0U0fhXYRus2ckkEohBTkga0pjqfoQaBOCA@mail.gmail.com>
 <20180822062631.5664-1-omosnace@redhat.com>
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Cc: linux-crypto@vger.kernel.org,
        Stephan Mueller <smueller@chronox.de>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Marcelo Henrique Cerri <marcelo.cerri@canonical.com>,
        "Leonidas S . Barbosa" <leo.barbosa@canonical.com>,
        Paulo Flabiano Smorigo <pfsmorigo@linux.vnet.ibm.com>,
        linuxppc-dev@lists.ozlabs.org, stable@vger.kernel.org
To: Ondrej Mosnacek <omosnace@redhat.com>
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In-Reply-To: <20180822062631.5664-1-omosnace@redhat.com>
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On Wed, Aug 22, 2018 at 08:26:31AM +0200, Ondrej Mosnacek wrote:
> This patch fixes sleep-in-atomic bugs in AES-CBC and AES-XTS VMX
> implementations. The problem is that the blkcipher_* functions should
> not be called in atomic context.
> 
> The bugs can be reproduced via the AF_ALG interface by trying to
> encrypt/decrypt sufficiently large buffers (at least 64 KiB) using the
> VMX implementations of 'cbc(aes)' or 'xts(aes)'. Such operations then
> trigger BUG in crypto_yield():
> 
> [  891.863680] BUG: sleeping function called from invalid context at include/crypto/algapi.h:424
> [  891.864622] in_atomic(): 1, irqs_disabled(): 0, pid: 12347, name: kcapi-enc
> [  891.864739] 1 lock held by kcapi-enc/12347:
> [  891.864811]  #0: 00000000f5d42c46 (sk_lock-AF_ALG){+.+.}, at: skcipher_recvmsg+0x50/0x530
> [  891.865076] CPU: 5 PID: 12347 Comm: kcapi-enc Not tainted 4.19.0-0.rc0.git3.1.fc30.ppc64le #1
> [  891.865251] Call Trace:
> [  891.865340] [c0000003387578c0] [c000000000d67ea4] dump_stack+0xe8/0x164 (unreliable)
> [  891.865511] [c000000338757910] [c000000000172a58] ___might_sleep+0x2f8/0x310
> [  891.865679] [c000000338757990] [c0000000006bff74] blkcipher_walk_done+0x374/0x4a0
> [  891.865825] [c0000003387579e0] [d000000007e73e70] p8_aes_cbc_encrypt+0x1c8/0x260 [vmx_crypto]
> [  891.865993] [c000000338757ad0] [c0000000006c0ee0] skcipher_encrypt_blkcipher+0x60/0x80
> [  891.866128] [c000000338757b10] [c0000000006ec504] skcipher_recvmsg+0x424/0x530
> [  891.866283] [c000000338757bd0] [c000000000b00654] sock_recvmsg+0x74/0xa0
> [  891.866403] [c000000338757c10] [c000000000b00f64] ___sys_recvmsg+0xf4/0x2f0
> [  891.866515] [c000000338757d90] [c000000000b02bb8] __sys_recvmsg+0x68/0xe0
> [  891.866631] [c000000338757e30] [c00000000000bbe4] system_call+0x5c/0x70
> 
> Fixes: 8c755ace357c ("crypto: vmx - Adding CBC routines for VMX module")
> Fixes: c07f5d3da643 ("crypto: vmx - Adding support for XTS")
> Cc: stable@vger.kernel.org
> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>

Patch applied.  Thanks.
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
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