Split the old READ_IMPLIES_EXEC workaround from executable PT_GNU_STACK
now that toolchains long support PT_GNU_STACK marking and there's no
need anymore to force modern programs into having all its user mappings
executable instead of only the stack and the PROT_EXEC ones. Disable
that automatic READ_IMPLIES_EXEC forcing on x86-64 and arm64. Add tables
documenting how READ_IMPLIES_EXEC is handled on x86-64, arm and arm64.
By Kees Cook.
arm64/elf: Disable automatic READ_IMPLIES_EXEC for 64-bit address spaces
With arm64 64-bit environments, there should never be a need for automatic
READ_IMPLIES_EXEC, as the architecture has always been execute-bit aware
(as in, the default memory protection should be NX unless a region
explicitly requests to be executable).
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>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lkml.kernel.org/r/20200327064820.12602-7-keescook@chromium.org
2 files changed
