If a bootstrap ELF contains a PT_GNU_STACK phdr, take stack protection
from there. Otherwise, default to VM_PROT_ALL.
---
include/mach/exec/elf.h | 1 +
include/mach/exec/exec.h | 2 ++
kern/elf-load.c | 7 +++
3 files changed, 10 insertions(+)
diff --git a/include/mach/exec/elf.h b/include/mach/exec/elf.h
index 409947c4..42920e25 100644
--- a/include/mach/exec/elf.h
+++ b/include/mach/exec/elf.h
@@ -300,6 +300,7 @@ typedef struct {
#define PT_NOTE4
#define PT_SHLIB 5
#define PT_PHDR6
+#define PT_GNU_STACK 0x6474e551
#define PT_LOPROC 0x7000
#define PT_HIPROC 0x7fff
diff --git a/include/mach/exec/exec.h b/include/mach/exec/exec.h
index 94b234b0..29fa897d 100644
--- a/include/mach/exec/exec.h
+++ b/include/mach/exec/exec.h
@@ -51,6 +51,8 @@ typedef struct exec_info
/* (ELF) Address of interpreter string for loading shared libraries,
null if none. */
vm_offset_t interp;
+ /* Required stack protection. */
+ vm_prot_t stack_prot;
} exec_info_t;
typedef int exec_sectype_t;
diff --git a/kern/elf-load.c b/kern/elf-load.c
index ce86327c..596233a8 100644
--- a/kern/elf-load.c
+++ b/kern/elf-load.c
@@ -73,6 +73,8 @@ int exec_load(exec_read_func_t *read, exec_read_exec_func_t
*read_exec,
if (actual < phsize)
return EX_CORRUPT;
+ out_info->stack_prot = VM_PROT_ALL;
+
for (i = 0; i < x.e_phnum; i++)
{
ph = (Elf_Phdr *)((vm_offset_t)phdr + i * x.e_phentsize);
@@ -89,6 +91,11 @@ int exec_load(exec_read_func_t *read, exec_read_exec_func_t
*read_exec,
ph->p_vaddr + loadbase,
ph->p_memsz, type);
if (result)
return result;
+ } else if (ph->p_type == PT_GNU_STACK) {
+ out_info->stack_prot = 0;
+ if (ph->p_flags & PF_R) out_info->stack_prot |=
VM_PROT_READ;
+ if (ph->p_flags & PF_W) out_info->stack_prot |=
VM_PROT_WRITE;
+ if (ph->p_flags & PF_X) out_info->stack_prot |=
VM_PROT_EXECUTE;
}
}
--
2.44.0