kernel/crypto/ahash.c, branch linux-5.1.y

crypto: ahash - fix another early termination in hash walk

2019-02-08T07:30:08Z

Hash algorithms with an alignmask set, e.g. "xcbc(aes-aesni)" and "michael_mic", fail the improved hash tests because they sometimes produce the wrong digest. The bug is that in the case where a scatterlist element crosses pages, not all the data is actually hashed because the scatterlist walk terminates too early. This happens because the 'nbytes' variable in crypto_hash_walk_done() is assigned the number of bytes remaining in the page, then later interpreted as the number of bytes remaining in the scatterlist element. Fix it. Fixes: 900a081f6912 ("crypto: ahash - Fix early termination in hash walk") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: hash - 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. 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. Note: we can't set CRYPTO_TFM_NEED_KEY for OPTIONAL_KEY algorithms, so ->setkey() for those must nevertheless be atomic. That's fine for now since only the crc32 and crc32c algorithms set OPTIONAL_KEY, and it's not intended that OPTIONAL_KEY be used much. [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: 9fa68f620041 ("crypto: hash - prevent using keyed hashes without setting key") Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: user - fix use_after_free of struct xxx_request

2018-12-07T06:15:00Z

All crypto_stats functions use the struct xxx_request for feeding stats, but in some case this structure could already be freed. For fixing this, the needed parameters (len and alg) will be stored before the request being executed. Fixes: cac5818c25d0 ("crypto: user - Implement a generic crypto statistics") Reported-by: syzbot Signed-off-by: Corentin Labbe 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: user - Implement a generic crypto statistics

2018-09-28T04:46:25Z

This patch implement a generic way to get statistics about all crypto usages. Signed-off-by: Corentin Labbe Signed-off-by: Herbert Xu

crypto: hash - Remove VLA usage

2018-09-04T03:35:03Z

In the quest to remove all stack VLA usage from the kernel[1], this removes the VLAs in SHASH_DESC_ON_STACK (via crypto_shash_descsize()) by using the maximum allowable size (which is now more clearly captured in a macro), along with a few other cases. Similar limits are turned into macros as well. A review of existing sizes shows that SHA512_DIGEST_SIZE (64) is the largest digest size and that sizeof(struct sha3_state) (360) is the largest descriptor size. The corresponding maximums are reduced. [1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com Signed-off-by: Kees Cook Signed-off-by: Herbert Xu

crypto: ahash - Fix early termination in hash walk

2018-03-30T17:34:19Z

When we have an unaligned SG list entry where there is no leftover aligned data, the hash walk code will incorrectly return zero as if the entire SG list has been processed. This patch fixes it by moving onto the next page instead. Reported-by: Eli Cooper Cc: Signed-off-by: Herbert Xu

crypto: hash - Require export/import in ahash

2018-02-15T15:24:59Z

Export and import are mandatory in async hash. As drivers were rewritten, drop empty wrappers and correct init of ahash transformation. Signed-off-by: Kamil Konieczny Signed-off-by: Herbert Xu

crypto: hash - prevent using keyed hashes without setting key

2018-01-12T12:03:37Z

Currently, almost none of the keyed hash algorithms check whether a key has been set before proceeding. Some algorithms are okay with this and will effectively just use a key of all 0's or some other bogus default. However, others will severely break, as demonstrated using "hmac(sha3-512-generic)", the unkeyed use of which causes a kernel crash via a (potentially exploitable) stack buffer overflow. A while ago, this problem was solved for AF_ALG by pairing each hash transform with a 'has_key' bool. However, there are still other places in the kernel where userspace can specify an arbitrary hash algorithm by name, and the kernel uses it as unkeyed hash without checking whether it is really unkeyed. Examples of this include: - KEYCTL_DH_COMPUTE, via the KDF extension - dm-verity - dm-crypt, via the ESSIV support - dm-integrity, via the "internal hash" mode with no key given - drbd (Distributed Replicated Block Device) This bug is especially bad for KEYCTL_DH_COMPUTE as that requires no privileges to call. Fix the bug for all users by adding a flag CRYPTO_TFM_NEED_KEY to the ->crt_flags of each hash transform that indicates whether the transform still needs to be keyed or not. Then, make the hash init, import, and digest functions return -ENOKEY if the key is still needed. The new flag also replaces the 'has_key' bool which algif_hash was previously using, thereby simplifying the algif_hash implementation. Reported-by: syzbot Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu

crypto: hash - introduce crypto_hash_alg_has_setkey()

2018-01-12T12:03:09Z

Templates that use an shash spawn can use crypto_shash_alg_has_setkey() to determine whether the underlying algorithm requires a key or not. But there was no corresponding function for ahash spawns. Add it. Note that the new function actually has to support both shash and ahash algorithms, since the ahash API can be used with either. Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu