[PATCH v2 06/20] htl: Respect GL(dl_stack_flags) when allocating stacks
Sergey Bugaev
bugaevc@gmail.com
Sat Mar 23 17:32:47 GMT 2024
Previously, HTL would always allocate non-executable stacks. This has
never been noticed, since GNU Mach on x86 ignores VM_PROT_EXECUTE and
makes all pages implicitly executable. Since GNU Mach on AArch64
supports non-executable pages, HTL forgetting to pass VM_PROT_EXECUTE
immediately breaks any code that (unfortunately, still) relies on
executable stacks.
Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>
---
sysdeps/htl/Versions | 4 ++++
sysdeps/mach/htl/pt-stack-alloc.c | 9 +++++++--
2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/sysdeps/htl/Versions b/sysdeps/htl/Versions
index 3a3b1e8b..7b5450d2 100644
--- a/sysdeps/htl/Versions
+++ b/sysdeps/htl/Versions
@@ -12,4 +12,8 @@ libc {
pthread_spin_destroy; pthread_spin_init; pthread_spin_lock;
pthread_spin_trylock; pthread_spin_unlock;
}
+
+ GLIBC_PRIVATE {
+ __vm_map;
+ }
}
diff --git a/sysdeps/mach/htl/pt-stack-alloc.c b/sysdeps/mach/htl/pt-stack-alloc.c
index 61974bd5..0597770b 100644
--- a/sysdeps/mach/htl/pt-stack-alloc.c
+++ b/sysdeps/mach/htl/pt-stack-alloc.c
@@ -31,9 +31,14 @@ int
__pthread_stack_alloc (void **stackaddr, size_t stacksize)
{
error_t err;
+ vm_prot_t prot = VM_PROT_READ | VM_PROT_WRITE;
- err = __vm_allocate (__mach_task_self (), (vm_offset_t *) stackaddr,
- stacksize, TRUE);
+ if (GL(dl_stack_flags) & PF_X)
+ prot |= VM_PROT_EXECUTE;
+
+ err = __vm_map (__mach_task_self (), (vm_offset_t *) stackaddr,
+ stacksize, 0, TRUE, MEMORY_OBJECT_NULL, 0, FALSE,
+ prot, VM_PROT_ALL, VM_INHERIT_COPY);
if (err == KERN_NO_SPACE)
err = EAGAIN;
--
2.44.0
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