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2022-02-04lib/crypto: blake2s: avoid indirect calls to compression function for Clang CFIJason A. Donenfeld1-2/+2
blake2s_compress_generic is weakly aliased by blake2s_compress. The current harness for function selection uses a function pointer, which is ordinarily inlined and resolved at compile time. But when Clang's CFI is enabled, CFI still triggers when making an indirect call via a weak symbol. This seems like a bug in Clang's CFI, as though it's bucketing weak symbols and strong symbols differently. It also only seems to trigger when "full LTO" mode is used, rather than "thin LTO". [ 0.000000][ T0] Kernel panic - not syncing: CFI failure (target: blake2s_compress_generic+0x0/0x1444) [ 0.000000][ T0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.16.0-mainline-06981-g076c855b846e #1 [ 0.000000][ T0] Hardware name: MT6873 (DT) [ 0.000000][ T0] Call trace: [ 0.000000][ T0] dump_backtrace+0xfc/0x1dc [ 0.000000][ T0] dump_stack_lvl+0xa8/0x11c [ 0.000000][ T0] panic+0x194/0x464 [ 0.000000][ T0] __cfi_check_fail+0x54/0x58 [ 0.000000][ T0] __cfi_slowpath_diag+0x354/0x4b0 [ 0.000000][ T0] blake2s_update+0x14c/0x178 [ 0.000000][ T0] _extract_entropy+0xf4/0x29c [ 0.000000][ T0] crng_initialize_primary+0x24/0x94 [ 0.000000][ T0] rand_initialize+0x2c/0x6c [ 0.000000][ T0] start_kernel+0x2f8/0x65c [ 0.000000][ T0] __primary_switched+0xc4/0x7be4 [ 0.000000][ T0] Rebooting in 5 seconds.. Nonetheless, the function pointer method isn't so terrific anyway, so this patch replaces it with a simple boolean, which also gets inlined away. This successfully works around the Clang bug. In general, I'm not too keen on all of the indirection involved here; it clearly does more harm than good. Hopefully the whole thing can get cleaned up down the road when lib/crypto is overhauled more comprehensively. But for now, we go with a simple bandaid. Fixes: 6048fdcc5f26 ("lib/crypto: blake2s: include as built-in") Link: https://github.com/ClangBuiltLinux/linux/issues/1567 Reported-by: Miles Chen <miles.chen@mediatek.com> Tested-by: Miles Chen <miles.chen@mediatek.com> Tested-by: Nathan Chancellor <nathan@kernel.org> Tested-by: John Stultz <john.stultz@linaro.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2021-01-03crypto: blake2s - share the "shash" API boilerplate codeEric Biggers1-67/+9
Add helper functions for shash implementations of BLAKE2s to include/crypto/internal/blake2s.h, taking advantage of __blake2s_update() and __blake2s_final() that were added by the previous patch to share more code between the library and shash implementations. crypto_blake2s_setkey() and crypto_blake2s_init() are usable as shash_alg::setkey and shash_alg::init directly, while crypto_blake2s_update() and crypto_blake2s_final() take an extra 'blake2s_compress_t' function pointer parameter. This allows the implementation of the compression function to be overridden, which is the only part that optimized implementations really care about. The new functions are inline functions (similar to those in sha1_base.h, sha256_base.h, and sm3_base.h) because this avoids needing to add a new module blake2s_helpers.ko, they aren't *too* long, and this avoids indirect calls which are expensive these days. Note that they can't go in blake2s_generic.ko, as that would require selecting CRYPTO_BLAKE2S from CRYPTO_BLAKE2S_X86, which would cause a recursive dependency. Finally, use these new helper functions in the x86 implementation of BLAKE2s. (This part should be a separate patch, but unfortunately the x86 implementation used the exact same function names like "crypto_blake2s_update()", so it had to be updated at the same time.) Signed-off-by: Eric Biggers <ebiggers@google.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2021-01-03crypto: blake2s - remove unneeded includesEric Biggers1-2/+0
It doesn't make sense for the generic implementation of BLAKE2s to include <crypto/internal/simd.h> and <linux/jump_label.h>, as these are things that would only be useful in an architecture-specific implementation. Remove these unnecessary includes. Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2021-01-03crypto: blake2s - define shash_alg structs using macrosEric Biggers1-61/+27
The shash_alg structs for the four variants of BLAKE2s are identical except for the algorithm name, driver name, and digest size. So, avoid code duplication by using a macro to define these structs. Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2020-01-09crypto: remove CRYPTO_TFM_RES_BAD_KEY_LENEric Biggers1-3/+1
The CRYPTO_TFM_RES_BAD_KEY_LEN flag was apparently meant as a way to make the ->setkey() functions provide more information about errors. However, no one actually checks for this flag, which makes it pointless. Also, many algorithms fail to set this flag when given a bad length key. Reviewing just the generic implementations, this is the case for aes-fixed-time, cbcmac, echainiv, nhpoly1305, pcrypt, rfc3686, rfc4309, rfc7539, rfc7539esp, salsa20, seqiv, and xcbc. But there are probably many more in arch/*/crypto/ and drivers/crypto/. Some algorithms can even set this flag when the key is the correct length. For example, authenc and authencesn set it when the key payload is malformed in any way (not just a bad length), the atmel-sha and ccree drivers can set it if a memory allocation fails, and the chelsio driver sets it for bad auth tag lengths, not just bad key lengths. So even if someone actually wanted to start checking this flag (which seems unlikely, since it's been unused for a long time), there would be a lot of work needed to get it working correctly. But it would probably be much better to go back to the drawing board and just define different return values, like -EINVAL if the key is invalid for the algorithm vs. -EKEYREJECTED if the key was rejected by a policy like "no weak keys". That would be much simpler, less error-prone, and easier to test. So just remove this flag. Signed-off-by: Eric Biggers <ebiggers@google.com> Reviewed-by: Horia Geantă <horia.geanta@nxp.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2019-11-17crypto: blake2s - implement generic shash driverArd Biesheuvel1-0/+171
Wire up our newly added Blake2s implementation via the shash API. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>