From 4b5e576fc21931969c0a1b53fdaf7ce3bfcebb86 Mon Sep 17 00:00:00 2001 From: Sergey Bugaev Date: Mon, 26 Jun 2023 02:17:48 +0300 Subject: hurd: Map brk non-executable The rest of the heap (backed by individual pages) is already mapped RW. Mapping these pages RWX presents a security hazard. Also, in another branch memory gets allocated using vm_allocate, which sets memory protection to VM_PROT_DEFAULT (which is RW). The mismatch between protections prevents Mach from coalescing the VM map entries. Signed-off-by: Sergey Bugaev Message-Id: <20230625231751.404120-2-bugaevc@gmail.com> --- sysdeps/mach/hurd/brk.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/sysdeps/mach/hurd/brk.c b/sysdeps/mach/hurd/brk.c index f1349495f5..3a335194f5 100644 --- a/sysdeps/mach/hurd/brk.c +++ b/sysdeps/mach/hurd/brk.c @@ -106,7 +106,7 @@ _hurd_set_brk (vm_address_t addr) /* First finish allocation. */ err = __vm_protect (__mach_task_self (), pagebrk, alloc_start - pagebrk, 0, - VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); + VM_PROT_READ|VM_PROT_WRITE); if (! err) _hurd_brk = alloc_start; @@ -120,7 +120,7 @@ _hurd_set_brk (vm_address_t addr) else /* Make the memory accessible. */ err = __vm_protect (__mach_task_self (), pagebrk, pagend - pagebrk, - 0, VM_PROT_READ|VM_PROT_WRITE|VM_PROT_EXECUTE); + 0, VM_PROT_READ|VM_PROT_WRITE); if (err) return __hurd_fail (err); -- cgit 1.4.1