From 8762606ae22e71ec65249cdbf809e3dc7ea8ea1e Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Thu, 1 Jun 2023 09:00:28 -0700 Subject: riscv/purgatory: Do not use fortified string functions MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit With the addition of -fstrict-flex-arrays=3, struct sha256_state's trailing array is no longer ignored by CONFIG_FORTIFY_SOURCE: struct sha256_state { u32 state[SHA256_DIGEST_SIZE / 4]; u64 count; u8 buf[SHA256_BLOCK_SIZE]; }; This means that the memcpy() calls with "buf" as a destination in sha256.c's code will attempt to perform run-time bounds checking, which could lead to calling missing functions, specifically a potential WARN_ONCE, which isn't callable from purgatory. Reported-by: Thorsten Leemhuis Closes: https://lore.kernel.org/lkml/175578ec-9dec-7a9c-8d3a-43f24ff86b92@leemhuis.info/ Bisected-by: "Joan Bruguera Micó" Fixes: df8fc4e934c1 ("kbuild: Enable -fstrict-flex-arrays=3") Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Cc: Masahiro Yamada Cc: Conor Dooley Cc: Nick Desaulniers Cc: Alyssa Ross Cc: Heiko Stuebner Cc: "Gustavo A. R. Silva" Cc: linux-riscv@lists.infradead.org Signed-off-by: Kees Cook Reviewed-by: Conor Dooley Reviewed-by: Palmer Dabbelt Acked-by: Palmer Dabbelt Link: https://lore.kernel.org/r/20230601160025.gonna.868-kees@kernel.org --- arch/riscv/purgatory/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/riscv/purgatory') diff --git a/arch/riscv/purgatory/Makefile b/arch/riscv/purgatory/Makefile index 5730797a6b40..8c73360c42bb 100644 --- a/arch/riscv/purgatory/Makefile +++ b/arch/riscv/purgatory/Makefile @@ -31,7 +31,7 @@ $(obj)/strncmp.o: $(srctree)/arch/riscv/lib/strncmp.S FORCE $(obj)/sha256.o: $(srctree)/lib/crypto/sha256.c FORCE $(call if_changed_rule,cc_o_c) -CFLAGS_sha256.o := -D__DISABLE_EXPORTS +CFLAGS_sha256.o := -D__DISABLE_EXPORTS -D__NO_FORTIFY CFLAGS_string.o := -D__DISABLE_EXPORTS CFLAGS_ctype.o := -D__DISABLE_EXPORTS -- cgit v1.2.3