current->personality & READ_IMPLIES_EXEC is currently being set for AArch64 binaries, resulting in an executable stack, when no explicit PT_GNU_STACK header is present.
[kmcmarti@sedition ~]$ uname -p aarch64 [kmcmarti@sedition ~]$ cat /proc/$$/personality 00400000 The reason for this is, without an explicit PT_GNU_STACK entry in the binary, stk is still set to EXSTACK_DEFAULT (which should be non-executable on AArch64.) As a result, elf_read_implies_exec is true, and we set READ_IMPLIES_EXEC in binfmt_elf.c:load_elf_binary. Fix this to return 0 in the native case, and parrot the logic from arch/arm/kernel/elf.c otherwise. With this patch, binaries correctly don't have READ_IMPLIES_EXEC set, and we can let PT_GNU_STACK change things if it's explicitly requested. Signed-off-by: Kyle McMartin <[email protected]> --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -114,7 +114,8 @@ typedef struct user_fpsimd_state elf_fpregset_t; */ #define elf_check_arch(x) ((x)->e_machine == EM_AARCH64) -#define elf_read_implies_exec(ex,stk) (stk != EXSTACK_DISABLE_X) +#define elf_read_implies_exec(ex,stk) (test_thread_flag(TIF_32BIT) \ + ? (stk == EXSTACK_ENABLE_X) : 0) #define CORE_DUMP_USE_REGSET #define ELF_EXEC_PAGESIZE PAGE_SIZE -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
