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x86: Add types to indirectly called assembly functions

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With CONFIG_CFI_CLANG, assembly functions indirectly called
from C code must be annotated with type identifiers to pass CFI
checking. Define the __CFI_TYPE helper macro to match the compiler
generated function preamble, and ensure SYM_TYPED_FUNC_START also
emits ENDBR with IBT.

Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220908215504.3686827-21-samitolvanen@google.com
This commit is contained in:
Sami Tolvanen 2022-09-08 14:55:02 -07:00 committed by Kees Cook
parent ca7e10bff1
commit ccace936ee
3 changed files with 17 additions and 3 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

5
arch/x86/crypto/blowfish-x86_64-asm_64.S
View file

@ -6,6 +6,7 @@
*/
#include <linux/linkage.h>
#include <linux/cfi_types.h>
.file "blowfish-x86_64-asm.S"
.text
@ -141,7 +142,7 @@ SYM_FUNC_START(__blowfish_enc_blk)
RET;
SYM_FUNC_END(__blowfish_enc_blk)
SYM_FUNC_START(blowfish_dec_blk)
SYM_TYPED_FUNC_START(blowfish_dec_blk)
/* input:
* %rdi: ctx
* %rsi: dst
@ -332,7 +333,7 @@ SYM_FUNC_START(__blowfish_enc_blk_4way)
RET;
SYM_FUNC_END(__blowfish_enc_blk_4way)
SYM_FUNC_START(blowfish_dec_blk_4way)
SYM_TYPED_FUNC_START(blowfish_dec_blk_4way)
/* input:
* %rdi: ctx
* %rsi: dst

12
arch/x86/include/asm/linkage.h
View file

@ -43,6 +43,18 @@
#endif /* __ASSEMBLY__ */
#define __CFI_TYPE(name) \
SYM_START(__cfi_##name, SYM_L_LOCAL, SYM_A_NONE) \
.fill 11, 1, 0x90 ASM_NL \
.byte 0xb8 ASM_NL \
.long __kcfi_typeid_##name ASM_NL \
SYM_FUNC_END(__cfi_##name)
/* SYM_TYPED_FUNC_START -- use for indirectly called globals, w/ CFI type */
#define SYM_TYPED_FUNC_START(name) \
SYM_TYPED_START(name, SYM_L_GLOBAL, SYM_A_ALIGN) \
ENDBR
/* SYM_FUNC_START -- use for global functions */
#define SYM_FUNC_START(name) \
SYM_START(name, SYM_L_GLOBAL, SYM_A_ALIGN) \

3
arch/x86/lib/memcpy_64.S
View file

@ -2,6 +2,7 @@
/* Copyright 2002 Andi Kleen */
#include <linux/linkage.h>
#include <linux/cfi_types.h>
#include <asm/errno.h>
#include <asm/cpufeatures.h>
#include <asm/alternative.h>
@ -27,7 +28,7 @@
* Output:
* rax original destination
*/
SYM_FUNC_START(__memcpy)
SYM_TYPED_FUNC_START(__memcpy)
ALTERNATIVE_2 "jmp memcpy_orig", "", X86_FEATURE_REP_GOOD, \
"jmp memcpy_erms", X86_FEATURE_ERMS