From d2a02e3c8bb6b347818518edff5a4b40ff52d6d8 Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Wed, 19 Jan 2022 14:35:06 +0100 Subject: lib/crypto: blake2s: avoid indirect calls to compression function for Clang CFI 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 Tested-by: Miles Chen Tested-by: Nathan Chancellor Tested-by: John Stultz Acked-by: Nick Desaulniers Reviewed-by: Eric Biggers Signed-off-by: Jason A. Donenfeld --- lib/crypto/blake2s.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'lib/crypto/blake2s.c') diff --git a/lib/crypto/blake2s.c b/lib/crypto/blake2s.c index 9364f79937b8..c71c09621c09 100644 --- a/lib/crypto/blake2s.c +++ b/lib/crypto/blake2s.c @@ -18,14 +18,14 @@ void blake2s_update(struct blake2s_state *state, const u8 *in, size_t inlen) { - __blake2s_update(state, in, inlen, blake2s_compress); + __blake2s_update(state, in, inlen, false); } EXPORT_SYMBOL(blake2s_update); void blake2s_final(struct blake2s_state *state, u8 *out) { WARN_ON(IS_ENABLED(DEBUG) && !out); - __blake2s_final(state, out, blake2s_compress); + __blake2s_final(state, out, false); memzero_explicit(state, sizeof(*state)); } EXPORT_SYMBOL(blake2s_final); -- cgit From 2d16803c562ecc644803d42ba98a8e0aef9c014e Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Sat, 28 May 2022 21:44:07 +0200 Subject: crypto: blake2s - remove shash module BLAKE2s has no currently known use as an shash. Just remove all of this unnecessary plumbing. Removing this shash was something we talked about back when we were making BLAKE2s a built-in, but I simply never got around to doing it. So this completes that project. Importantly, this fixs a bug in which the lib code depends on crypto_simd_disabled_for_test, causing linker errors. Also add more alignment tests to the selftests and compare SIMD and non-SIMD compression functions, to make up for what we lose from testmgr.c. Reported-by: gaochao Cc: Eric Biggers Cc: Ard Biesheuvel Cc: stable@vger.kernel.org Fixes: 6048fdcc5f26 ("lib/crypto: blake2s: include as built-in") Signed-off-by: Jason A. Donenfeld Signed-off-by: Herbert Xu --- lib/crypto/blake2s.c | 37 ++++++++++++++++++++++++++++++------- 1 file changed, 30 insertions(+), 7 deletions(-) (limited to 'lib/crypto/blake2s.c') diff --git a/lib/crypto/blake2s.c b/lib/crypto/blake2s.c index c71c09621c09..98e688c6d891 100644 --- a/lib/crypto/blake2s.c +++ b/lib/crypto/blake2s.c @@ -16,16 +16,44 @@ #include #include +static inline void blake2s_set_lastblock(struct blake2s_state *state) +{ + state->f[0] = -1; +} + void blake2s_update(struct blake2s_state *state, const u8 *in, size_t inlen) { - __blake2s_update(state, in, inlen, false); + const size_t fill = BLAKE2S_BLOCK_SIZE - state->buflen; + + if (unlikely(!inlen)) + return; + if (inlen > fill) { + memcpy(state->buf + state->buflen, in, fill); + blake2s_compress(state, state->buf, 1, BLAKE2S_BLOCK_SIZE); + state->buflen = 0; + in += fill; + inlen -= fill; + } + if (inlen > BLAKE2S_BLOCK_SIZE) { + const size_t nblocks = DIV_ROUND_UP(inlen, BLAKE2S_BLOCK_SIZE); + blake2s_compress(state, in, nblocks - 1, BLAKE2S_BLOCK_SIZE); + in += BLAKE2S_BLOCK_SIZE * (nblocks - 1); + inlen -= BLAKE2S_BLOCK_SIZE * (nblocks - 1); + } + memcpy(state->buf + state->buflen, in, inlen); + state->buflen += inlen; } EXPORT_SYMBOL(blake2s_update); void blake2s_final(struct blake2s_state *state, u8 *out) { WARN_ON(IS_ENABLED(DEBUG) && !out); - __blake2s_final(state, out, false); + blake2s_set_lastblock(state); + memset(state->buf + state->buflen, 0, + BLAKE2S_BLOCK_SIZE - state->buflen); /* Padding */ + blake2s_compress(state, state->buf, 1, state->buflen); + cpu_to_le32_array(state->h, ARRAY_SIZE(state->h)); + memcpy(out, state->h, state->outlen); memzero_explicit(state, sizeof(*state)); } EXPORT_SYMBOL(blake2s_final); @@ -38,12 +66,7 @@ static int __init blake2s_mod_init(void) return 0; } -static void __exit blake2s_mod_exit(void) -{ -} - module_init(blake2s_mod_init); -module_exit(blake2s_mod_exit); MODULE_LICENSE("GPL v2"); MODULE_DESCRIPTION("BLAKE2s hash function"); MODULE_AUTHOR("Jason A. Donenfeld "); -- cgit