Delete the msyscall mechanism entirely, since mimmutable+pinsyscalls has

replaced it with a more strict mechanism, which happens to be lockless O(1)
rather than micro-lock O(1)+O(log N).  Also nop-out the sys_msyscall(2) guts,
but leave the syscall around for a bit longer so that people can build through
it, since ld.so(1) still wants to call it.

4 files changed, 17 insertions, 23 deletions

diff --git a/sys/kern/exec_elf.c b/sys/kern/exec_elf.c
index 33e5cadb76a..0cb3b15968f 100644
--- a/sys/kern/exec_elf.c
+++ b/sys/kern/exec_elf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: exec_elf.c,v 1.185 2024/01/17 22:22:25 kurt Exp $	*/
+/*	$OpenBSD: exec_elf.c,v 1.186 2024/04/02 08:39:16 deraadt Exp $	*/
 
 /*
  * Copyright (c) 1996 Per Fogelstrom
@@ -494,10 +494,15 @@ elf_load_file(struct proc *p, char *path, struct exec_package *epp,
 				addr = ph[i].p_vaddr - base_ph->p_vaddr;
 			}
 			elf_load_psection(&epp->ep_vmcmds, nd.ni_vp,
-			    &ph[i], &addr, &size, &prot, flags | VMCMD_SYSCALL);
+			    &ph[i], &addr, &size, &prot, flags);
 			/* If entry is within this section it must be text */
 			if (eh.e_entry >= ph[i].p_vaddr &&
 			    eh.e_entry < (ph[i].p_vaddr + size)) {
+				/* LOAD containing e_entry may not be writable */
+				if (prot & PROT_WRITE) {
+					error = ENOEXEC;
+					goto bad1;
+				}
  				epp->ep_entry = addr + eh.e_entry -
 				    ELF_TRUNC(ph[i].p_vaddr,ph[i].p_align);
 				if (flags == VMCMD_RELATIVE)
@@ -715,7 +720,7 @@ exec_elf_makecmds(struct proc *p, struct exec_package *epp)
 	 */
 	for (i = 0, pp = ph; i < eh->e_phnum; i++, pp++) {
 		Elf_Addr addr, size = 0;
-		int prot = 0, syscall = 0;
+		int prot = 0;
 		int flags = 0;
 
 		switch (pp->p_type) {
@@ -731,16 +736,9 @@ exec_elf_makecmds(struct proc *p, struct exec_package *epp)
 			} else
 				addr = ELF_NO_ADDR;
 
-			/*
-			 * Permit system calls in main-text static binaries.
-			 * static binaries may not call msyscall() or
-			 * pinsyscalls()
-			 */
-			if (interp == NULL) {
-				syscall = VMCMD_SYSCALL;
-				p->p_vmspace->vm_map.flags |= VM_MAP_SYSCALL_ONCE;
+			/* Static binaries may not call pinsyscalls() */
+			if (interp == NULL)
 				p->p_vmspace->vm_map.flags |= VM_MAP_PINSYSCALL_ONCE;
-			}
 
 			/*
 			 * Calculates size of text and data segments
@@ -750,7 +748,7 @@ exec_elf_makecmds(struct proc *p, struct exec_package *epp)
 			 * for DATA_PLT, is fine for TEXT_PLT.
 			 */
 			elf_load_psection(&epp->ep_vmcmds, epp->ep_vp,
-			    pp, &addr, &size, &prot, flags | textrel | syscall);
+			    pp, &addr, &size, &prot, flags | textrel);
 
 			/*
 			 * Update exe_base in case alignment was off.
diff --git a/sys/kern/exec_subr.c b/sys/kern/exec_subr.c
index a02566bf797..4ebca1b981d 100644
--- a/sys/kern/exec_subr.c
+++ b/sys/kern/exec_subr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: exec_subr.c,v 1.66 2023/03/19 20:32:13 kettenis Exp $	*/
+/*	$OpenBSD: exec_subr.c,v 1.67 2024/04/02 08:39:16 deraadt Exp $	*/
 /*	$NetBSD: exec_subr.c,v 1.9 1994/12/04 03:10:42 mycroft Exp $	*/
 
 /*
@@ -194,9 +194,6 @@ vmcmd_map_pagedvn(struct proc *p, struct exec_vmcmd *cmd)
 	/*
 	 * do the map
 	 */
-	if ((cmd->ev_flags & VMCMD_SYSCALL) && (cmd->ev_prot & PROT_EXEC))
-		flags |= UVM_FLAG_SYSCALL;
-
 	error = uvm_map(&p->p_vmspace->vm_map, &cmd->ev_addr, cmd->ev_len,
 	    uobj, cmd->ev_offset, 0,
 	    UVM_MAPFLAG(cmd->ev_prot, PROT_MASK, MAP_INHERIT_COPY,
@@ -217,8 +214,7 @@ vmcmd_map_pagedvn(struct proc *p, struct exec_vmcmd *cmd)
 			    round_page(cmd->ev_addr + cmd->ev_len), 1);
 #ifdef PMAP_CHECK_COPYIN
 		if (PMAP_CHECK_COPYIN &&
-		    ((flags & UVM_FLAG_SYSCALL) ||
-		    ((cmd->ev_flags & VMCMD_IMMUTABLE) && (cmd->ev_prot & PROT_EXEC))))
+		    ((cmd->ev_flags & VMCMD_IMMUTABLE) && (cmd->ev_prot & PROT_EXEC)))
 			uvm_map_check_copyin_add(&p->p_vmspace->vm_map,
 			    cmd->ev_addr, round_page(cmd->ev_addr + cmd->ev_len));
 #endif
diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c
index b4816b2e9a0..d571b0855cf 100644
--- a/sys/kern/init_main.c
+++ b/sys/kern/init_main.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: init_main.c,v 1.325 2024/02/14 06:17:51 miod Exp $	*/
+/*	$OpenBSD: init_main.c,v 1.326 2024/04/02 08:39:16 deraadt Exp $	*/
 /*	$NetBSD: init_main.c,v 1.84.4.1 1996/06/02 09:08:06 mrg Exp $	*/
 
 /*
@@ -626,7 +626,7 @@ start_init(void *arg)
 	    NULL, UVM_UNKNOWN_OFFSET, 0,
 	    UVM_MAPFLAG(PROT_READ | PROT_WRITE, PROT_MASK, MAP_INHERIT_COPY,
 	    MADV_NORMAL,
-	    UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW|UVM_FLAG_STACK|UVM_FLAG_SYSCALL)))
+	    UVM_FLAG_FIXED|UVM_FLAG_OVERLAY|UVM_FLAG_COPYONW|UVM_FLAG_STACK)))
 		panic("init: couldn't allocate argument space");
 
 	for (pathp = &initpaths[0]; (path = *pathp) != NULL; pathp++) {
diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
index a00e2372145..7d87a4cbcb9 100644
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: kern_exec.c,v 1.254 2024/01/17 18:56:13 deraadt Exp $	*/
+/*	$OpenBSD: kern_exec.c,v 1.255 2024/04/02 08:39:16 deraadt Exp $	*/
 /*	$NetBSD: kern_exec.c,v 1.75 1996/02/09 18:59:28 christos Exp $	*/
 
 /*-
@@ -905,7 +905,7 @@ exec_sigcode_map(struct process *pr)
 	if (uvm_map(&pr->ps_vmspace->vm_map, &pr->ps_sigcode, round_page(sz),
 	    sigobject, 0, 0, UVM_MAPFLAG(PROT_EXEC,
 	    PROT_READ | PROT_WRITE | PROT_EXEC, MAP_INHERIT_COPY,
-	    MADV_RANDOM, UVM_FLAG_COPYONW | UVM_FLAG_SYSCALL))) {
+	    MADV_RANDOM, UVM_FLAG_COPYONW))) {
 		uao_detach(sigobject);
 		return (ENOMEM);
 	}