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2018-08-03crypto: skcipher - fix crash flushing dcache in error pathEric Biggers1-26/+27
scatterwalk_done() is only meant to be called after a nonzero number of bytes have been processed, since scatterwalk_pagedone() will flush the dcache of the *previous* page. But in the error case of skcipher_walk_done(), e.g. if the input wasn't an integer number of blocks, scatterwalk_done() was actually called after advancing 0 bytes. This caused a crash ("BUG: unable to handle kernel paging request") during '!PageSlab(page)' on architectures like arm and arm64 that define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE, provided that the input was page-aligned as in that case walk->offset == 0. Fix it by reorganizing skcipher_walk_done() to skip the scatterwalk_advance() and scatterwalk_done() if an error has occurred. This bug was found by syzkaller fuzzing. Reproducer, assuming ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE: #include <linux/if_alg.h> #include <sys/socket.h> #include <unistd.h> int main() { struct sockaddr_alg addr = { .salg_type = "skcipher", .salg_name = "cbc(aes-generic)", }; char buffer[4096] __attribute__((aligned(4096))) = { 0 }; int fd; fd = socket(AF_ALG, SOCK_SEQPACKET, 0); bind(fd, (void *)&addr, sizeof(addr)); setsockopt(fd, SOL_ALG, ALG_SET_KEY, buffer, 16); fd = accept(fd, NULL, NULL); write(fd, buffer, 15); read(fd, buffer, 15); } Reported-by: Liu Chao <liuchao741@huawei.com> Fixes: b286d8b1a690 ("crypto: skcipher - Add skcipher walk interface") Cc: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-08-03crypto: skcipher - remove unnecessary setting of walk->nbytesEric Biggers1-1/+0
Setting 'walk->nbytes = walk->total' in skcipher_walk_first() doesn't make sense because actually walk->nbytes needs to be set to the length of the first step in the walk, which may be less than walk->total. This is done by skcipher_walk_next() which is called immediately afterwards. Also walk->nbytes was already set to 0 in skcipher_walk_skcipher(), which is a better default value in case it's forgotten to be set later. Therefore, remove the unnecessary assignment to walk->nbytes. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-08-03crypto: skcipher - fix aligning block size in skcipher_copy_iv()Eric Biggers1-1/+1
The ALIGN() macro needs to be passed the alignment, not the alignmask (which is the alignment minus 1). Fixes: b286d8b1a690 ("crypto: skcipher - Add skcipher walk interface") Cc: <stable@vger.kernel.org> # v4.10+ Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-07-01crypto: skcipher - remove the exporting of skcipher_walk_nextDenis Efremov1-1/+0
The function skcipher_walk_next declared as static and marked as EXPORT_SYMBOL_GPL. It's a bit confusing for internal function to be exported. The area of visibility for such function is its .c file and all other modules. Other *.c files of the same module can't use it, despite all other modules can. Relying on the fact that this is the internal function and it's not a crucial part of the API, the patch just removes the EXPORT_SYMBOL_GPL marking of skcipher_walk_next. Found by Linux Driver Verification project (linuxtesting.org). Signed-off-by: Denis Efremov <efremov@linux.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-01-12crypto: skcipher - prevent using skciphers without setting keyEric Biggers1-4/+26
Similar to what was done for the hash API, update the skcipher API to track whether each transform has been keyed, and reject encryption/decryption if a key is needed but one hasn't been set. This isn't as important as the equivalent fix for the hash API because symmetric ciphers almost always require a key (the "null cipher" is the only exception), so are unlikely to be used without one. Still, tracking the key will prevent accidental unkeyed use. algif_skcipher also had to track the key anyway, so the new flag replaces that and simplifies the algif_skcipher implementation. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-12-11crypto: skcipher - set walk.iv for zero-length inputsEric Biggers1-6/+4
All the ChaCha20 algorithms as well as the ARM bit-sliced AES-XTS algorithms call skcipher_walk_virt(), then access the IV (walk.iv) before checking whether any bytes need to be processed (walk.nbytes). But if the input is empty, then skcipher_walk_virt() doesn't set the IV, and the algorithms crash trying to use the uninitialized IV pointer. Fix it by setting the IV earlier in skcipher_walk_virt(). Also fix it for the AEAD walk functions. This isn't a perfect solution because we can't actually align the IV to ->cra_alignmask unless there are bytes to process, for one because the temporary buffer for the aligned IV is freed by skcipher_walk_done(), which is only called when there are bytes to process. Thus, algorithms that require aligned IVs will still need to avoid accessing the IV when walk.nbytes == 0. Still, many algorithms/architectures are fine with IVs having any alignment, and even for those that aren't, a misaligned pointer bug is much less severe than an uninitialized pointer bug. This change also matches the behavior of the older blkcipher_walk API. Fixes: 0cabf2af6f5a ("crypto: skcipher - Fix crash on zero-length input") Reported-by: syzbot <syzkaller@googlegroups.com> Cc: <stable@vger.kernel.org> # v4.14+ Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-11-28Merge branch 'linus' of ↵Linus Torvalds1-0/+3
git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6 Pull crypto fixes from Herbert Xu: - avoid potential bogus alignment for some AEAD operations - fix crash in algif_aead - avoid sleeping in softirq context with async af_alg * 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: crypto: skcipher - Fix skcipher_walk_aead_common crypto: af_alg - remove locking in async callback crypto: algif_aead - skip SGL entries with NULL page
2017-11-25crypto: skcipher - Fix skcipher_walk_aead_commonOndrej Mosnáček1-0/+3
The skcipher_walk_aead_common function calls scatterwalk_copychunks on the input and output walks to skip the associated data. If the AD end at an SG list entry boundary, then after these calls the walks will still be pointing to the end of the skipped region. These offsets are later checked for alignment in skcipher_walk_next, so the skcipher_walk may detect the alignment incorrectly. This patch fixes it by calling scatterwalk_done after the copychunks calls to ensure that the offsets refer to the right SG list entry. Fixes: b286d8b1a690 ("crypto: skcipher - Add skcipher walk interface") Cc: <stable@vger.kernel.org> Signed-off-by: Ondrej Mosnacek <omosnacek@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-10-07crypto: skcipher - Fix crash on zero-length inputHerbert Xu1-6/+11
The skcipher walk interface doesn't handle zero-length input properly as the old blkcipher walk interface did. This is due to the fact that the length check is done too late. This patch moves the length check forward so that it does the right thing. Fixes: b286d8b1a690 ("crypto: skcipher - Add skcipher walk...") Cc: <stable@vger.kernel.org> Reported-by: Stephan Müller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-05-18crypto: skcipher - Add missing API setkey checksHerbert Xu1-1/+39
The API setkey checks for key sizes and alignment went AWOL during the skcipher conversion. This patch restores them. Cc: <stable@vger.kernel.org> Fixes: 4e6c3df4d729 ("crypto: skcipher - Add low-level skcipher...") Reported-by: Baozeng <sploving1@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-01-13crypto: Replaced gcc specific attributes with macros from compiler.hGideon Israel Dsouza1-1/+2
Continuing from this commit: 52f5684c8e1e ("kernel: use macros from compiler.h instead of __attribute__((...))") I submitted 4 total patches. They are part of task I've taken up to increase compiler portability in the kernel. I've cleaned up the subsystems under /kernel /mm /block and /security, this patch targets /crypto. There is <linux/compiler.h> which provides macros for various gcc specific constructs. Eg: __weak for __attribute__((weak)). I've cleaned all instances of gcc specific attributes with the right macros for the crypto subsystem. I had to make one additional change into compiler-gcc.h for the case when one wants to use this: __attribute__((aligned) and not specify an alignment factor. From the gcc docs, this will result in the largest alignment for that data type on the target machine so I've named the macro __aligned_largest. Please advise if another name is more appropriate. Signed-off-by: Gideon Israel Dsouza <gidisrael@gmail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-12-30crypto: skcipher - introduce walksize attribute for SIMD algosArd Biesheuvel1-8/+12
In some cases, SIMD algorithms can only perform optimally when allowed to operate on multiple input blocks in parallel. This is especially true for bit slicing algorithms, which typically take the same amount of time processing a single block or 8 blocks in parallel. However, other SIMD algorithms may benefit as well from bigger strides. So add a walksize attribute to the skcipher algorithm definition, and wire it up to the skcipher walk API. To avoid confusion between the skcipher and AEAD attributes, rename the skcipher_walk chunksize attribute to 'stride', and set it from the walksize (in the skcipher case) or from the chunksize (in the AEAD case). Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-12-14crypto: skcipher - fix crash in virtual walkArd Biesheuvel1-1/+3
The new skcipher walk API may crash in the following way. (Interestingly, the tcrypt boot time tests seem unaffected, while an explicit test using the module triggers it) Unable to handle kernel NULL pointer dereference at virtual address 00000000 ... [<ffff000008431d84>] __memcpy+0x84/0x180 [<ffff0000083ec0d0>] skcipher_walk_done+0x328/0x340 [<ffff0000080c5c04>] ctr_encrypt+0x84/0x100 [<ffff000008406d60>] simd_skcipher_encrypt+0x88/0x98 [<ffff0000083fa05c>] crypto_rfc3686_crypt+0x8c/0x98 [<ffff0000009b0900>] test_skcipher_speed+0x518/0x820 [tcrypt] [<ffff0000009b31c0>] do_test+0x1408/0x3b70 [tcrypt] [<ffff0000009bd050>] tcrypt_mod_init+0x50/0x1000 [tcrypt] [<ffff0000080838f4>] do_one_initcall+0x44/0x138 [<ffff0000081aee60>] do_init_module+0x68/0x1e0 [<ffff0000081524d0>] load_module+0x1fd0/0x2458 [<ffff000008152c38>] SyS_finit_module+0xe0/0xf0 [<ffff0000080836f0>] el0_svc_naked+0x24/0x28 This is due to the fact that skcipher_done_slow() may be entered with walk->buffer unset. Since skcipher_walk_done() already deals with the case where walk->buffer == walk->page, it appears to be the intention that walk->buffer point to walk->page after skcipher_next_slow(), so ensure that is the case. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-12-01crypto: skcipher - Add separate walker for AEAD decryptionHerbert Xu1-3/+30
The AEAD decrypt interface includes the authentication tag in req->cryptlen. Therefore we need to exlucde that when doing a walk over it. This patch adds separate walker functions for AEAD encryption and decryption. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
2016-11-30crypto: skcipher - fix crash in skcipher_walk_aead()Ard Biesheuvel1-0/+2
The new skcipher_walk_aead() may crash in the following way due to the walk flag SKCIPHER_WALK_PHYS not being cleared at the start of the walk: Unable to handle kernel NULL pointer dereference at virtual address 00000001 [..] Internal error: Oops: 96000044 [#1] PREEMPT SMP [..] PC is at skcipher_walk_next+0x208/0x450 LR is at skcipher_walk_next+0x1e4/0x450 pc : [<ffff2b93b7104e20>] lr : [<ffff2b93b7104dfc>] pstate: 40000045 sp : ffffb925fa517940 [...] [<ffff2b93b7104e20>] skcipher_walk_next+0x208/0x450 [<ffff2b93b710535c>] skcipher_walk_first+0x54/0x148 [<ffff2b93b7105664>] skcipher_walk_aead+0xd4/0x108 [<ffff2b93b6e77928>] ccm_encrypt+0x68/0x158 So clear the flag at the appropriate time. Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-11-28crypto: skcipher - Add skcipher walk interfaceHerbert Xu1-0/+511
This patch adds the skcipher walk interface which replaces both blkcipher walk and ablkcipher walk. Just like blkcipher walk it can also be used for AEAD algorithms. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-07-18crypto: skcipher - Remove top-level givcipher interfaceHerbert Xu1-2/+2
This patch removes the old crypto_grab_skcipher helper and replaces it with crypto_grab_skcipher2. As this is the final entry point into givcipher this patch also removes all traces of the top-level givcipher interface, including all implicit IV generators such as chainiv. The bottom-level givcipher interface remains until the drivers using it are converted. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-07-18crypto: skcipher - Add low-level skcipher interfaceHerbert Xu1-7/+189
This patch allows skcipher algorithms and instances to be created and registered with the crypto API. They are accessible through the top-level skcipher interface, along with ablkcipher/blkcipher algorithms and instances. This patch also introduces a new parameter called chunk size which is meant for ciphers such as CTR and CTS which ostensibly can handle arbitrary lengths, but still behave like block ciphers in that you can only process a partial block at the very end. For these ciphers the block size will continue to be set to 1 as it is now while the chunk size will be set to the underlying block size. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-01-25crypto: skcipher - Add default key size helperHerbert Xu1-2/+2
While converting ecryptfs over to skcipher I found that it needs to pick a default key size if one isn't given. Rather than having it poke into the guts of the algorithm to get max_keysize, let's provide a helper that is meant to give a sane default (just in case we ever get an algorithm that has no maximum key size). Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-01-18crypto: skcipher - Add crypto_skcipher_has_setkeyHerbert Xu1-0/+2
This patch adds a way for skcipher users to determine whether a key is required by a transform. Cc: stable@vger.kernel.org Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-10-01crypto: skcipher - blkcipher and ablkcipher should it be staticGeliang Tang1-2/+2
Fixes the following sparse warnings: crypto/skcipher.c:94:5: warning: symbol 'crypto_init_skcipher_ops_blkcipher' was not declared. Should it be static? crypto/skcipher.c:185:5: warning: symbol 'crypto_init_skcipher_ops_ablkcipher' was not declared. Should it be static? Signed-off-by: Geliang Tang <geliangtang@163.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-08-21crypto: skcipher - Add top-level skcipher interfaceHerbert Xu1-0/+245
This patch introduces the crypto skcipher interface which aims to replace both blkcipher and ablkcipher. It's very similar to the existing ablkcipher interface. The main difference is the removal of the givcrypt interface. In order to make the transition easier for blkcipher users, there is a helper SKCIPHER_REQUEST_ON_STACK which can be used to place a request on the stack for synchronous transforms. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>