Jason A. Donenfeld d2a02e3c8b 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: 6048fdcc5f ("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>		2022-02-04 19:22:32 +01:00
..
aes.c
arc4.c
blake2s-generic.c	lib/crypto: blake2s: include as built-in	2022-01-07 00:25:25 +01:00
blake2s-selftest.c	lib/crypto: blake2s: move hmac construction into wireguard	2022-01-18 13:03:55 +01:00
blake2s.c	lib/crypto: blake2s: avoid indirect calls to compression function for Clang CFI	2022-02-04 19:22:32 +01:00
chacha.c
chacha20poly1305-selftest.c
chacha20poly1305.c
curve25519-fiat32.c
curve25519-generic.c
curve25519-hacl64.c
curve25519-selftest.c
curve25519.c
des.c
Kconfig	lib/crypto: add prompts back to crypto libraries	2022-01-18 13:03:55 +01:00
libchacha.c
Makefile	lib/crypto: blake2s: include as built-in	2022-01-07 00:25:25 +01:00
poly1305-donna32.c
poly1305-donna64.c
poly1305.c
sha256.c
sm4.c	crypto: sm4 - Do not change section of ck and sbox	2021-09-17 11:05:10 +08:00