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authorKees Cook <keescook@chromium.org>2023-05-31 03:33:48 +0300
committerKees Cook <keescook@chromium.org>2023-06-01 21:24:51 +0300
commit91218d7d708ed2f4b77323ca70a948b8334dd767 (patch)
tree8d7a53c8c740fcb2b9d41183a472f7cf3cedec9e /arch/x86/purgatory
parent41e7a72e1d3ca62560ec1ef1f4529e7a4c4ad8a3 (diff)
downloadlinux-91218d7d708ed2f4b77323ca70a948b8334dd767.tar.xz
x86/purgatory: Do not use fortified string functions
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 <linux@leemhuis.info> Closes: https://lore.kernel.org/lkml/175578ec-9dec-7a9c-8d3a-43f24ff86b92@leemhuis.info/ Bisected-by: "Joan Bruguera Micó" <joanbrugueram@gmail.com> Fixes: df8fc4e934c1 ("kbuild: Enable -fstrict-flex-arrays=3") Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: x86@kernel.org Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org> Cc: Alyssa Ross <hi@alyssa.is> Cc: Sami Tolvanen <samitolvanen@google.com> Cc: Alexander Potapenko <glider@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Tested-by: Thorsten Leemhuis <linux@leemhuis.info> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Link: https://lore.kernel.org/r/20230531003345.never.325-kees@kernel.org
Diffstat (limited to 'arch/x86/purgatory')
-rw-r--r--arch/x86/purgatory/Makefile2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/purgatory/Makefile b/arch/x86/purgatory/Makefile
index 82fec66d46d2..005324d6c76b 100644
--- a/arch/x86/purgatory/Makefile
+++ b/arch/x86/purgatory/Makefile
@@ -12,7 +12,7 @@ $(obj)/string.o: $(srctree)/arch/x86/boot/compressed/string.c 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
# When linking purgatory.ro with -r unresolved symbols are not checked,
# also link a purgatory.chk binary without -r to check for unresolved symbols.