From: deraadt <deraadt@openbsd.org>
Date: Sun, 23 Oct 2022 02:53:14 +0000 (+0000)
Subject: A better workaround for mips64 mimmutable problem.  The problem is the
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=cbad891aa6955d10455f123e2808514aeaf1f197;p=openbsd

A better workaround for mips64 mimmutable problem.  The problem is the
DT_DEBUG word is inside a R LOAD that gets marked immutable, but ld.so
does a mprotect RW + adjustment + mprotect R.  DT_DEBUG is specified as
being inside the DYNAMIC range, solet's do all the immutables and then,
 on mips64 only, turn around and make DYNAMIC mutable.  That gives us
time to see if we can move DT_DEBUG or change what ld.so is doing.
discussed at length with kettenis
---

diff --git a/sys/kern/exec_elf.c b/sys/kern/exec_elf.c
index d65c637a52f..9643714413e 100644
--- a/sys/kern/exec_elf.c
+++ b/sys/kern/exec_elf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: exec_elf.c,v 1.170 2022/10/22 15:06:47 deraadt Exp $	*/
+/*	$OpenBSD: exec_elf.c,v 1.171 2022/10/23 02:53:14 deraadt Exp $	*/
 
 /*
  * Copyright (c) 1996 Per Fogelstrom
@@ -201,9 +201,6 @@ elf_load_psection(struct exec_vmcmd_set *vcset, struct vnode *vp,
 	if ((ph->p_flags & (PF_X | PF_W)) != (PF_X | PF_W) &&
 	    (ph->p_flags & PF_OPENBSD_MUTABLE) == 0)
 		flags |= VMCMD_IMMUTABLE;
-#if defined (__mips__)
-	flags &= ~VMCMD_IMMUTABLE;	/* DT_DEBUG is not ready on mips */
-#endif
 
 	msize = ph->p_memsz + diff;
 	offset = ph->p_offset - bdiff;
@@ -427,7 +424,6 @@ elf_load_file(struct proc *p, char *path, struct exec_package *epp,
 			addr += size;
 			break;
 
-		case PT_DYNAMIC:
 		case PT_PHDR:
 		case PT_NOTE:
 			break;
@@ -442,6 +438,13 @@ elf_load_file(struct proc *p, char *path, struct exec_package *epp,
 			    ph[i].p_memsz, ph[i].p_vaddr + pos, NULLVP, 0, 0);
 			break;
 
+		case PT_DYNAMIC:
+#if defined (__mips__)
+			/* DT_DEBUG is not ready on mips */
+			NEW_VMCMD(&epp->ep_vmcmds, vmcmd_mutable,
+			    ph[i].p_memsz, ph[i].p_vaddr + pos, NULLVP, 0, 0);
+#endif
+			break;
 		case PT_GNU_RELRO:
 		case PT_OPENBSD_MUTABLE:
 			NEW_VMCMD(&epp->ep_vmcmds, vmcmd_mutable,
@@ -652,7 +655,6 @@ exec_elf_makecmds(struct proc *p, struct exec_package *epp)
 
 		case PT_INTERP:
 			/* Already did this one */
-		case PT_DYNAMIC:
 		case PT_NOTE:
 			break;
 
@@ -671,6 +673,13 @@ exec_elf_makecmds(struct proc *p, struct exec_package *epp)
 			    ph[i].p_memsz, ph[i].p_vaddr + exe_base, NULLVP, 0, 0);
 			break;
 
+		case PT_DYNAMIC:
+#if defined (__mips__)
+			/* DT_DEBUG is not ready on mips */
+			NEW_VMCMD(&epp->ep_vmcmds, vmcmd_mutable,
+			    ph[i].p_memsz, ph[i].p_vaddr + exe_base, NULLVP, 0, 0);
+#endif
+			break;
 		case PT_GNU_RELRO:
 		case PT_OPENBSD_MUTABLE:
 			NEW_VMCMD(&epp->ep_vmcmds, vmcmd_mutable,