diff options
Diffstat (limited to 'arch/x86/include/asm/elf.h')
| -rw-r--r-- | arch/x86/include/asm/elf.h | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h index 69c0f892e310..452beed7892b 100644 --- a/arch/x86/include/asm/elf.h +++ b/arch/x86/include/asm/elf.h @@ -281,9 +281,29 @@ extern u32 elf_hwcap2; /* * An executable for which elf_read_implies_exec() returns TRUE will * have the READ_IMPLIES_EXEC personality flag set automatically. + * + * The decision process for determining the results are: + * + * CPU: | lacks NX* | has NX, ia32 | has NX, x86_64 | + * ELF: | | | | + * ---------------------|------------|------------------|----------------| + * 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 | + * + * exec-all : all PROT_READ user mappings are executable, except when + * backed by files on a noexec-filesystem. + * exec-none : only PROT_EXEC user mappings are executable. + * exec-stack: only the stack and PROT_EXEC user mappings are executable. + * + * *this column has no architectural effect: NX markings are ignored by + * hardware, but may have behavioral effects when "wants X" collides with + * "cannot be X" constraints in memory permission flags, as in + * https://lkml.kernel.org/r/20190418055759.GA3155@mellanox.com + * */ #define elf_read_implies_exec(ex, executable_stack) \ - (executable_stack != EXSTACK_DISABLE_X) + (mmap_is_ia32() && executable_stack == EXSTACK_DEFAULT) struct task_struct; |