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vm_map_protect(): handle stack protection stored in the stack guard

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mprotect(2) on the stack region needs to adjust guard stored protection,
so that e.g. enable executing on stack worked properly on stack growth.

Reported by:	dchagin
Reviewed by:	alc, markj
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D41099
This commit is contained in:
Konstantin Belousov 2023-07-25 16:32:28 +03:00
parent 79169929f0
commit 55be6be12c
1 changed files with 23 additions and 4 deletions
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27
sys/vm/vm_map.c
View file

@ -2726,7 +2726,22 @@ static void
vm_map_protect_guard(vm_map_entry_t entry, vm_prot_t new_prot,
vm_prot_t new_maxprot, int flags)
{
vm_prot_t old_prot;
MPASS((entry->eflags & MAP_ENTRY_GUARD) != 0);
if ((entry->eflags & (MAP_ENTRY_STACK_GAP_UP |
MAP_ENTRY_STACK_GAP_DN)) == 0)
return;
old_prot = PROT_EXTRACT(entry->offset);
if ((flags & VM_MAP_PROTECT_SET_MAXPROT) != 0) {
entry->offset = PROT_MAX(new_maxprot) |
(new_maxprot & old_prot);
}
if ((flags & VM_MAP_PROTECT_SET_PROT) != 0) {
entry->offset = new_prot | PROT_MAX(
PROT_MAX_EXTRACT(entry->offset));
}
}
/*
@ -2742,7 +2757,7 @@ vm_map_protect(vm_map_t map, vm_offset_t start, vm_offset_t end,
vm_map_entry_t entry, first_entry, in_tran, prev_entry;
vm_object_t obj;
struct ucred *cred;
vm_prot_t check_prot, old_prot;
vm_prot_t check_prot, max_prot, old_prot;
int rv;
if (start == end)
@ -2791,10 +2806,14 @@ again:
vm_map_unlock(map);
return (KERN_INVALID_ARGUMENT);
}
if ((entry->eflags & MAP_ENTRY_GUARD) != 0) {
if ((entry->eflags & (MAP_ENTRY_GUARD |
MAP_ENTRY_STACK_GAP_DN | MAP_ENTRY_STACK_GAP_UP)) ==
MAP_ENTRY_GUARD)
continue;
}
if (!CONTAINS_BITS(entry->max_protection, check_prot)) {
max_prot = (entry->eflags & (MAP_ENTRY_STACK_GAP_DN |
MAP_ENTRY_STACK_GAP_UP)) != 0 ?
PROT_MAX_EXTRACT(entry->offset) : entry->max_protection;
if (!CONTAINS_BITS(max_prot, check_prot)) {
vm_map_unlock(map);
return (KERN_PROTECTION_FAILURE);
}