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Add elf image flag to disable stack gap.

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Reviewed by:	markj
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D22379
This commit is contained in:
Konstantin Belousov 2019-11-17 14:54:07 +00:00
parent 01a2b5679b
commit 156e865494
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=354790
2 changed files with 6 additions and 2 deletions
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1
sys/sys/elf_common.h
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@ -784,6 +784,7 @@ typedef struct {
/* NT_FREEBSD_FEATURE_CTL desc[0] bits */
#define NT_FREEBSD_FCTL_ASLR_DISABLE 0x00000001
#define NT_FREEBSD_FCTL_PROTMAX_DISABLE 0x00000002
#define NT_FREEBSD_FCTL_STKGAP_DISABLE 0x00000004
/* Values for n_type. Used in core files. */
#define NT_PRSTATUS 1 /* Process status. */

7
sys/vm/vm_map.c
View File

@ -69,6 +69,7 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/elf.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/lock.h>
@ -4136,7 +4137,8 @@ vm_map_stack_locked(vm_map_t map, vm_offset_t addrbos, vm_size_t max_ssize,
addrbos + max_ssize > vm_map_max(map) ||
addrbos + max_ssize <= addrbos)
return (KERN_INVALID_ADDRESS);
sgp = (curproc->p_flag2 & P2_STKGAP_DISABLE) != 0 ? 0 :
sgp = ((curproc->p_flag2 & P2_STKGAP_DISABLE) != 0 ||
(curproc->p_fctl0 & NT_FREEBSD_FCTL_STKGAP_DISABLE) != 0) ? 0 :
(vm_size_t)stack_guard_page * PAGE_SIZE;
if (sgp >= max_ssize)
return (KERN_INVALID_ARGUMENT);
@ -4273,7 +4275,8 @@ vm_map_growstack(vm_map_t map, vm_offset_t addr, vm_map_entry_t gap_entry)
} else {
return (KERN_FAILURE);
}
guard = (curproc->p_flag2 & P2_STKGAP_DISABLE) != 0 ? 0 :
guard = ((curproc->p_flag2 & P2_STKGAP_DISABLE) != 0 ||
(curproc->p_fctl0 & NT_FREEBSD_FCTL_STKGAP_DISABLE) != 0) ? 0 :
gap_entry->next_read;
max_grow = gap_entry->end - gap_entry->start;
if (guard > max_grow)