From: liushuoran <liushuoran@huawei.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Xiakaixu <xiakaixu@huawei.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
"David S. Miller" <davem@davemloft.net>,
"Theodore Ts'o" <tytso@mit.edu>, Jaegeuk Kim <jaegeuk@kernel.org>,
"nhorman@tuxdriver.com" <nhorman@tuxdriver.com>,
"mh1@iki.fi" <mh1@iki.fi>,
"linux-crypto@vger.kernel.org" <linux-crypto@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Wangbintian <bintian.wang@huawei.com>,
Huxinwei <huxinwei@huawei.com>,
"zhangzhibin (C)" <zhangzhibin.zhang@huawei.com>
Subject: RE: Kernel panic - encryption/decryption failed when open file on Arm64
Date: Mon, 12 Sep 2016 02:16:30 +0000 [thread overview]
Message-ID: <00B10D30F2BAA743B48953A4D86C96D54C8A8A@SZXEMI506-MBS.china.huawei.com> (raw)
In-Reply-To: <CAKv+Gu8w+BuwxQjOtpnFPHnJNUzq7m0K+KJ8=FG2wHigaB54ng@mail.gmail.com>
Hi Ard,
Thanks for the prompt reply. With the patch, there is no panic anymore. But it seems that the encryption/decryption is not successful anyway.
As Herbert points out, "If the page allocation fails in blkcipher_walk_next it'll simply switch over to processing it block by block". So does that mean the encryption/decryption should be successful even if the page allocation fails? Please correct me if I misunderstand anything. Thanks in advance.
Regards,
Shuoran
> -----Original Message-----
> From: Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org]
> Sent: Friday, September 09, 2016 6:57 PM
> To: Xiakaixu
> Cc: Herbert Xu; David S. Miller; Theodore Ts'o; Jaegeuk Kim;
> nhorman@tuxdriver.com; mh1@iki.fi; linux-crypto@vger.kernel.org;
> linux-kernel@vger.kernel.org; Wangbintian; liushuoran; Huxinwei; zhangzhibin
> (C)
> Subject: Re: Kernel panic - encryption/decryption failed when open file on
> Arm64
>
> On 9 September 2016 at 11:31, Ard Biesheuvel <ard.biesheuvel@linaro.org>
> wrote:
> > On 9 September 2016 at 11:19, xiakaixu <xiakaixu@huawei.com> wrote:
> >> Hi,
> >>
> >> After a deeply research about this crash, seems it is a specific
> >> bug that only exists in armv8 board. And it occurs in this function
> >> in arch/arm64/crypto/aes-glue.c.
> >>
> >> static int ctr_encrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
> >> struct scatterlist *src, unsigned int nbytes)
> >> {
> >> ...
> >>
> >> desc->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP;
> >> blkcipher_walk_init(&walk, dst, src, nbytes);
> >> err = blkcipher_walk_virt_block(desc, &walk, AES_BLOCK_SIZE);
> --->
> >> page allocation failed
> >>
> >> ...
> >>
> >> while ((blocks = (walk.nbytes / AES_BLOCK_SIZE)))
> { ---->
> >> walk.nbytes = 0, and skip this loop
> >> aes_ctr_encrypt(walk.dst.virt.addr, walk.src.virt.addr,
> >> (u8 *)ctx->key_enc, rounds, blocks,
> walk.iv,
> >> first);
> >> ...
> >> err = blkcipher_walk_done(desc, &walk,
> >> walk.nbytes %
> AES_BLOCK_SIZE);
> >> }
> >> if (nbytes)
> { ---->
> >> enter this if() statement
> >> u8 *tdst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
> >> u8 *tsrc = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
> >> ...
> >>
> >> aes_ctr_encrypt(tail, tsrc, (u8 *)ctx->key_enc, rounds,
> >> ----> the the sencond input parameter is NULL, so crash...
> >> blocks, walk.iv, first);
> >> ...
> >> }
> >> ...
> >> }
> >>
> >>
> >> If the page allocation failed in the function blkcipher_walk_virt_block(),
> >> the variable walk.nbytes = 0, so it will skip the while() loop and enter
> >> the if(nbytes) statment. But here the varibale tsrc is NULL and it is also
> >> the sencond input parameter of the function aes_ctr_encrypt()... Kernel
> >> Panic...
> >>
> >> I have also researched the similar function in other architectures, and
> >> there if(walk.nbytes) is used, not this if(nbytes) statement in the armv8.
> >> so I think this armv8 function ctr_encrypt() should deal with the page
> >> allocation failed situation.
> >>
>
> Does this solve your problem?
>
> diff --git a/arch/arm64/crypto/aes-glue.c b/arch/arm64/crypto/aes-glue.c
> index 5c888049d061..6b2aa0fd6cd0 100644
> --- a/arch/arm64/crypto/aes-glue.c
> +++ b/arch/arm64/crypto/aes-glue.c
> @@ -216,7 +216,7 @@ static int ctr_encrypt(struct blkcipher_desc
> *desc, struct scatterlist *dst,
> err = blkcipher_walk_done(desc, &walk,
> walk.nbytes % AES_BLOCK_SIZE);
> }
> - if (nbytes) {
> + if (walk.nbytes % AES_BLOCK_SIZE) {
> u8 *tdst = walk.dst.virt.addr + blocks * AES_BLOCK_SIZE;
> u8 *tsrc = walk.src.virt.addr + blocks * AES_BLOCK_SIZE;
> u8 __aligned(8) tail[AES_BLOCK_SIZE];
next prev parent reply other threads:[~2016-09-12 2:17 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <57D15BD3.40903@huawei.com>
2016-09-08 12:47 ` Kernel panic - encryption/decryption failed when open file on Arm64 Herbert Xu
2016-09-09 4:08 ` xiakaixu
2016-09-09 10:19 ` xiakaixu
2016-09-09 10:31 ` Ard Biesheuvel
2016-09-09 10:56 ` Ard Biesheuvel
2016-09-12 2:16 ` liushuoran [this message]
2016-09-12 17:40 ` Ard Biesheuvel
2016-09-13 2:05 ` xiakaixu
2016-09-13 6:43 ` Herbert Xu
2016-09-13 7:56 ` Ard Biesheuvel
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