From: Paulo Flabiano Smorigo Subject: Re: [PATCH v2] crypto: vmx - Fix sleep-in-atomic bugs Date: Fri, 24 Aug 2018 16:47:14 -0300 Message-ID: References: <20180822062631.5664-1-omosnace@redhat.com> <20180823000446.GA26297@gallifrey> <11128af3ef7474136485261b5d53b679@linux.vnet.ibm.com> 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: <11128af3ef7474136485261b5d53b679@linux.vnet.ibm.com> Sender: stable-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org On 2018-08-23 17:34, Paulo Flabiano Smorigo wrote: > 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. Looks good to me. I made some tests here and no problem was found. -- Paulo Flabiano Smorigo IBM Linux Technology Center