kernel/crypto/skcipher.c, branch linux-5.2.y

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman

crypto: skcipher - don't WARN on unprocessed data after slow walk step

2019-04-08T06:42:55Z

skcipher_walk_done() assumes it's a bug if, after the "slow" path is executed where the next chunk of data is processed via a bounce buffer, the algorithm says it didn't process all bytes. Thus it WARNs on this. However, this can happen legitimately when the message needs to be evenly divisible into "blocks" but isn't, and the algorithm has a 'walksize' greater than the block size. For example, ecb-aes-neonbs sets 'walksize' to 128 bytes and only supports messages evenly divisible into 16-byte blocks. If, say, 17 message bytes remain but they straddle scatterlist elements, the skcipher_walk code will take the "slow" path and pass the algorithm all 17 bytes in the bounce buffer. But the algorithm will only be able to process 16 bytes, triggering the WARN. Fix this by just removing the WARN_ON(). Returning -EINVAL, as the code already does, is the right behavior. This bug was detected by my patches that improve testmgr to fuzz algorithms against their generic implementation. Fixes: b286d8b1a690 ("crypto: skcipher - Add skcipher walk interface") Cc: # v4.10+ Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: skcipher - set CRYPTO_TFM_NEED_KEY if ->setkey() fails

2019-01-18T10:40:24Z

Some algorithms have a ->setkey() method that is not atomic, in the sense that setting a key can fail after changes were already made to the tfm context. In this case, if a key was already set the tfm can end up in a state that corresponds to neither the old key nor the new key. For example, in lrw.c, if gf128mul_init_64k_bbe() fails due to lack of memory, then priv::table will be left NULL. After that, encryption with that tfm will cause a NULL pointer dereference. It's not feasible to make all ->setkey() methods atomic, especially ones that have to key multiple sub-tfms. Therefore, make the crypto API set CRYPTO_TFM_NEED_KEY if ->setkey() fails and the algorithm requires a key, to prevent the tfm from being used until a new key is set. [Cc stable mainly because when introducing the NEED_KEY flag I changed AF_ALG to rely on it; and unlike in-kernel crypto API users, AF_ALG previously didn't have this problem. So these "incompletely keyed" states became theoretically accessible via AF_ALG -- though, the opportunities for causing real mischief seem pretty limited.] Fixes: f8d33fac8480 ("crypto: skcipher - prevent using skciphers without setting key") Cc: # v4.16+ Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: skcipher - add helper for simple block cipher modes

2019-01-11T06:16:57Z

The majority of skcipher templates (including both the existing ones and the ones remaining to be converted from the "blkcipher" API) just wrap a single block cipher algorithm. This includes cbc, cfb, ctr, ecb, kw, ofb, and pcbc. Add a helper function skcipher_alloc_instance_simple() that handles allocating an skcipher instance for this common case. Signed-off-by: Eric Biggers Reviewed-by: Stephan Mueller Signed-off-by: Herbert Xu

crypto: skcipher - remove remnants of internal IV generators

2018-12-23T03:52:45Z

Remove dead code related to internal IV generators, which are no longer used since they've been replaced with the "seqiv" and "echainiv" templates. The removed code includes: - The "givcipher" (GIVCIPHER) algorithm type. No algorithms are registered with this type anymore, so it's unneeded. - The "const char *geniv" member of aead_alg, ablkcipher_alg, and blkcipher_alg. A few algorithms still set this, but it isn't used anymore except to show via /proc/crypto and CRYPTO_MSG_GETALG. Just hardcode "" or "" in those cases. - The 'skcipher_givcrypt_request' structure, which is never used. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: skcipher - add might_sleep() to skcipher_walk_virt()

2018-12-23T03:52:44Z

skcipher_walk_virt() can still sleep even with atomic=true, since that only affects the later calls to skcipher_walk_done(). But, skcipher_walk_virt() only has to allocate memory for some input data layouts, so incorrectly calling it with preemption disabled can go undetected. Use might_sleep() so that it's detected reliably. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: user - clean up report structure copying

2018-11-09T09:41:39Z

There have been a pretty ridiculous number of issues with initializing the report structures that are copied to userspace by NETLINK_CRYPTO. Commit 4473710df1f8 ("crypto: user - Prepare for CRYPTO_MAX_ALG_NAME expansion") replaced some strncpy()s with strlcpy()s, thereby introducing information leaks. Later two other people tried to replace other strncpy()s with strlcpy() too, which would have introduced even more information leaks: - https://lore.kernel.org/patchwork/patch/954991/ - https://patchwork.kernel.org/patch/10434351/ Commit cac5818c25d0 ("crypto: user - Implement a generic crypto statistics") also uses the buggy strlcpy() approach and therefore leaks uninitialized memory to userspace. A fix was proposed, but it was originally incomplete. Seeing as how apparently no one can get this right with the current approach, change all the reporting functions to: - Start by memsetting the report structure to 0. This guarantees it's always initialized, regardless of what happens later. - Initialize all strings using strscpy(). This is safe after the memset, ensures null termination of long strings, avoids unnecessary work, and avoids the -Wstringop-truncation warnings from gcc. - Use sizeof(var) instead of sizeof(type). This is more robust against copy+paste errors. For simplicity, also reuse the -EMSGSIZE return value from nla_put(). Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: skcipher - Introduce crypto_sync_skcipher

2018-09-28T04:46:06Z

In preparation for removal of VLAs due to skcipher requests on the stack via SKCIPHER_REQUEST_ON_STACK() usage, this introduces the infrastructure for the "sync skcipher" tfm, which is for handling the on-stack cases of skcipher, which are always non-ASYNC and have a known limited request size. The crypto API additions: struct crypto_sync_skcipher (wrapper for struct crypto_skcipher) crypto_alloc_sync_skcipher() crypto_free_sync_skcipher() crypto_sync_skcipher_setkey() crypto_sync_skcipher_get_flags() crypto_sync_skcipher_set_flags() crypto_sync_skcipher_clear_flags() crypto_sync_skcipher_blocksize() crypto_sync_skcipher_ivsize() crypto_sync_skcipher_reqtfm() skcipher_request_set_sync_tfm() SYNC_SKCIPHER_REQUEST_ON_STACK() (with tfm type check) Signed-off-by: Kees Cook Reviewed-by: Ard Biesheuvel Signed-off-by: Herbert Xu

crypto: skcipher - fix crash flushing dcache in error path

2018-08-03T10:06:04Z

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 #include #include 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 Fixes: b286d8b1a690 ("crypto: skcipher - Add skcipher walk interface") Cc: # v4.10+ Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: skcipher - remove unnecessary setting of walk->nbytes

2018-08-03T10:06:04Z

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 Signed-off-by: Herbert Xu