From: Paulo Flabiano Smorigo Subject: Re: [PATCH v2] crypto: vmx - Fix sleep-in-atomic bugs Date: Thu, 23 Aug 2018 17:34:27 -0300 Message-ID: <11128af3ef7474136485261b5d53b679@linux.vnet.ibm.com> References: <20180822062631.5664-1-omosnace@redhat.com> <20180823000446.GA26297@gallifrey> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Cc: Ondrej Mosnacek , Herbert Xu , linux-crypto@vger.kernel.org, Stephan Mueller , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , "Leonidas S . Barbosa" , linuxppc-dev@lists.ozlabs.org, stable@vger.kernel.org To: Marcelo Henrique Cerri Return-path: In-Reply-To: <20180823000446.GA26297@gallifrey> Sender: stable-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org On 2018-08-22 21:04, Marcelo Henrique Cerri wrote: > That looks good to me. Maybe Paulo can help testing it. > > -- > Regards, > Marcelo > > 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 >> --- >> Still untested, please test and review if possible. >> >> Changes in v2: >> - fix leaving preemtption, etc. disabled when leaving the function >> (I switched to the more obvious and less efficient variant for the >> sake of clarity.) >> >> drivers/crypto/vmx/aes_cbc.c | 30 ++++++++++++++---------------- >> drivers/crypto/vmx/aes_xts.c | 21 ++++++++++++++------- >> 2 files changed, 28 insertions(+), 23 deletions(-) >> >> diff --git a/drivers/crypto/vmx/aes_cbc.c >> b/drivers/crypto/vmx/aes_cbc.c >> index 5285ece4f33a..b71895871be3 100644 >> --- a/drivers/crypto/vmx/aes_cbc.c >> +++ b/drivers/crypto/vmx/aes_cbc.c >> @@ -107,24 +107,23 @@ static int p8_aes_cbc_encrypt(struct >> blkcipher_desc *desc, >> ret = crypto_skcipher_encrypt(req); >> skcipher_request_zero(req); >> } else { >> - preempt_disable(); >> - pagefault_disable(); >> - enable_kernel_vsx(); >> - >> blkcipher_walk_init(&walk, dst, src, nbytes); >> ret = blkcipher_walk_virt(desc, &walk); >> while ((nbytes = walk.nbytes)) { >> + preempt_disable(); >> + pagefault_disable(); >> + enable_kernel_vsx(); >> aes_p8_cbc_encrypt(walk.src.virt.addr, >> walk.dst.virt.addr, >> nbytes & AES_BLOCK_MASK, >> &ctx->enc_key, walk.iv, 1); >> + disable_kernel_vsx(); >> + pagefault_enable(); >> + preempt_enable(); >> + >> nbytes &= AES_BLOCK_SIZE - 1; >> ret = blkcipher_walk_done(desc, &walk, nbytes); >> } >> - >> - disable_kernel_vsx(); >> - pagefault_enable(); >> - preempt_enable(); >> } >> >> return ret; >> @@ -147,24 +146,23 @@ static int p8_aes_cbc_decrypt(struct >> blkcipher_desc *desc, >> ret = crypto_skcipher_decrypt(req); >> skcipher_request_zero(req); >> } else { >> - preempt_disable(); >> - pagefault_disable(); >> - enable_kernel_vsx(); >> - >> blkcipher_walk_init(&walk, dst, src, nbytes); >> ret = blkcipher_walk_virt(desc, &walk); >> while ((nbytes = walk.nbytes)) { >> + preempt_disable(); >> + pagefault_disable(); >> + enable_kernel_vsx(); >> aes_p8_cbc_encrypt(walk.src.virt.addr, >> walk.dst.virt.addr, >> nbytes & AES_BLOCK_MASK, >> &ctx->dec_key, walk.iv, 0); >> + disable_kernel_vsx(); >> + pagefault_enable(); >> + preempt_enable(); >> + >> nbytes &= AES_BLOCK_SIZE - 1; >> ret = blkcipher_walk_done(desc, &walk, nbytes); >> } >> - >> - disable_kernel_vsx(); >> - pagefault_enable(); >> - preempt_enable(); >> } >> >> return ret; >> diff --git a/drivers/crypto/vmx/aes_xts.c >> b/drivers/crypto/vmx/aes_xts.c >> index 8bd9aff0f55f..e9954a7d4694 100644 >> --- a/drivers/crypto/vmx/aes_xts.c >> +++ b/drivers/crypto/vmx/aes_xts.c >> @@ -116,32 +116,39 @@ static int p8_aes_xts_crypt(struct >> blkcipher_desc *desc, >> ret = enc? crypto_skcipher_encrypt(req) : >> crypto_skcipher_decrypt(req); >> skcipher_request_zero(req); >> } else { >> + blkcipher_walk_init(&walk, dst, src, nbytes); >> + >> + ret = blkcipher_walk_virt(desc, &walk); >> + >> preempt_disable(); >> pagefault_disable(); >> enable_kernel_vsx(); >> >> - blkcipher_walk_init(&walk, dst, src, nbytes); >> - >> - ret = blkcipher_walk_virt(desc, &walk); >> iv = walk.iv; >> memset(tweak, 0, AES_BLOCK_SIZE); >> aes_p8_encrypt(iv, tweak, &ctx->tweak_key); >> >> + disable_kernel_vsx(); >> + pagefault_enable(); >> + preempt_enable(); >> + >> while ((nbytes = walk.nbytes)) { >> + preempt_disable(); >> + pagefault_disable(); >> + enable_kernel_vsx(); >> if (enc) >> aes_p8_xts_encrypt(walk.src.virt.addr, walk.dst.virt.addr, >> nbytes & AES_BLOCK_MASK, &ctx->enc_key, NULL, tweak); >> else >> aes_p8_xts_decrypt(walk.src.virt.addr, walk.dst.virt.addr, >> nbytes & AES_BLOCK_MASK, &ctx->dec_key, NULL, tweak); >> + disable_kernel_vsx(); >> + pagefault_enable(); >> + preempt_enable(); >> >> nbytes &= AES_BLOCK_SIZE - 1; >> ret = blkcipher_walk_done(desc, &walk, nbytes); >> } >> - >> - disable_kernel_vsx(); >> - pagefault_enable(); >> - preempt_enable(); >> } >> return ret; >> } >> -- >> 2.17.1 >> Sure thing. I'll test it later today. Thanks Ondrej for the fix. -- Paulo Flabiano Smorigo IBM Linux Technology Center