Add pinsyscall(2). With this you can tell the kernel the location

(start,len) of the syscall stub in libc.so for a specified syscall
(using SYS_* notation).  Only SYS_execve is supported at this time.
ok gnezdo mortimer kettenis

diff --git a/sys/kern/syscalls.master b/sys/kern/syscalls.master
index d799adc..67a5424 100644 (file)
--- a/sys/kern/syscalls.master
+++ b/sys/kern/syscalls.master
@@ -1,4 +1,4 @@
-;      $OpenBSD: syscalls.master,v 1.243 2023/02/14 08:34:49 mvs Exp $
+;      $OpenBSD: syscalls.master,v 1.244 2023/02/16 04:42:06 deraadt Exp $
 ;      $NetBSD: syscalls.master,v 1.32 1996/04/23 10:24:21 mycroft Exp $
 
 ;      @(#)syscalls.master     8.2 (Berkeley) 1/13/94
@@ -284,7 +284,7 @@
 143    STD             { int sys_setthrname(pid_t tid, const char *name); }
 144    OBSOL           ogetrlimit
 145    OBSOL           osetrlimit
-146    OBSOL           okillpg
+146    STD NOLOCK      { int sys_pinsyscall(int syscall, void *addr, size_t len); }
 147    STD             { int sys_setsid(void); }
 148    STD             { int sys_quotactl(const char *path, int cmd, \
                            int uid, char *arg); }

diff --git a/sys/uvm/uvm_extern.h b/sys/uvm/uvm_extern.h
index 6f4ddc5..994957f 100644 (file)
--- a/sys/uvm/uvm_extern.h
+++ b/sys/uvm/uvm_extern.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: uvm_extern.h,v 1.166 2022/11/17 18:53:05 deraadt Exp $        */
+/*     $OpenBSD: uvm_extern.h,v 1.167 2023/02/16 04:42:07 deraadt Exp $        */
 /*     $NetBSD: uvm_extern.h,v 1.57 2001/03/09 01:02:12 chs Exp $      */
 
 /*
@@ -214,6 +214,8 @@ struct vmspace {
        caddr_t vm_daddr;       /* [I] user virtual address of data */
        caddr_t vm_maxsaddr;    /* [I] user VA at max stack growth */
        caddr_t vm_minsaddr;    /* [I] user VA at top of stack */
+       vaddr_t vm_execve;      /* [v] execve systemcall stub region */
+       vaddr_t vm_execve_end;  /* [v] execve systemcall stub region */
 };
 
 /*

diff --git a/sys/uvm/uvm_mmap.c b/sys/uvm/uvm_mmap.c
index e3dcd41..db0adcf 100644 (file)
--- a/sys/uvm/uvm_mmap.c
+++ b/sys/uvm/uvm_mmap.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: uvm_mmap.c,v 1.178 2023/02/11 23:22:19 deraadt Exp $  */
+/*     $OpenBSD: uvm_mmap.c,v 1.179 2023/02/16 04:42:08 deraadt Exp $  */
 /*     $NetBSD: uvm_mmap.c,v 1.49 2001/02/18 21:19:08 chs Exp $        */
 
 /*
@@ -68,6 +68,7 @@
 
 #include <machine/exec.h>      /* for __LDPGSZ */
 
+#include <sys/syscall.h>
 #include <sys/syscallargs.h>
 
 #include <uvm/uvm.h>
@@ -615,6 +616,38 @@ sys_msyscall(struct proc *p, void *v, register_t *retval)
        return uvm_map_syscall(&p->p_vmspace->vm_map, addr, addr+size);
 }
 
+/*
+ * sys_pinsyscall
+ */
+int
+sys_pinsyscall(struct proc *p, void *v, register_t *retval)
+{
+       struct sys_pinsyscall_args /* {
+               syscallarg(int) syscall;
+               syscallarg(void *) addr;
+               syscallarg(size_t) len;
+       } */ *uap = v;
+       struct vmspace *vm = p->p_vmspace;
+       vm_map_t map = &p->p_vmspace->vm_map;
+       vaddr_t start, end;
+
+       if (SCARG(uap, syscall) != SYS_execve)
+               return (EINVAL);
+       start = (vaddr_t)SCARG(uap, addr);
+       end = start + (vsize_t)SCARG(uap, len);
+       if (start >= end || start < map->min_offset || end > map->max_offset)
+               return (EFAULT);
+       vm_map_lock(map);
+       if (vm->vm_execve) {
+               vm_map_unlock(map);
+               return (EPERM);
+       }
+       vm->vm_execve = start;
+       vm->vm_execve_end = end;
+       vm_map_unlock(map);
+       return (0);
+}
+
 /*
  * sys_mimmutable: the mimmutable system call
  */