diff options
| author | Kees Cook <keescook@chromium.org> | 2020-03-27 07:48:17 +0100 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-04-20 19:24:33 +0200 |
| commit | 9fccc5c0c99f238aa1b0460fccbdb30a887e7036 (patch) | |
| tree | ce74f5ea115587fe836851a2c33f605360b1c608 /arch/x86/include | |
| parent | x86/elf: Split READ_IMPLIES_EXEC from executable PT_GNU_STACK (diff) | |
| download | linux-9fccc5c0c99f238aa1b0460fccbdb30a887e7036.tar.xz linux-9fccc5c0c99f238aa1b0460fccbdb30a887e7036.zip | |
x86/elf: Disable automatic READ_IMPLIES_EXEC on 64-bit
With modern x86 64-bit environments, there should never be a need for
automatic READ_IMPLIES_EXEC, as the architecture is intended to always
be execute-bit aware (as in, the default memory protection should be NX
unless a region explicitly requests to be executable).
There were very old x86_64 systems that lacked the NX bit, but for those,
the NX bit is, obviously, unenforceable, so these changes should have
no impact on them.
Suggested-by: Hector Marco-Gisbert <hecmargi@upv.es>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Link: https://lkml.kernel.org/r/20200327064820.12602-4-keescook@chromium.org
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/elf.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h index 397a1c74433e..452beed7892b 100644 --- a/arch/x86/include/asm/elf.h +++ b/arch/x86/include/asm/elf.h @@ -287,7 +287,7 @@ extern u32 elf_hwcap2; * CPU: | lacks NX* | has NX, ia32 | has NX, x86_64 | * ELF: | | | | * ---------------------|------------|------------------|----------------| - * missing PT_GNU_STACK | exec-all | exec-all | exec-all | + * missing PT_GNU_STACK | exec-all | exec-all | exec-none | * PT_GNU_STACK == RWX | exec-stack | exec-stack | exec-stack | * PT_GNU_STACK == RW | exec-none | exec-none | exec-none | * @@ -303,7 +303,7 @@ extern u32 elf_hwcap2; * */ #define elf_read_implies_exec(ex, executable_stack) \ - (executable_stack == EXSTACK_DEFAULT) + (mmap_is_ia32() && executable_stack == EXSTACK_DEFAULT) struct task_struct; |