From: deraadt <deraadt@openbsd.org>
Date: Mon, 7 Nov 2022 20:41:38 +0000 (+0000)
Subject: Since the introduction of automatic immutable from the kernel, the munmap()
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=a5c19628acd4b7d236fcd941d400b465dc027284;p=openbsd

Since the introduction of automatic immutable from the kernel, the munmap()
of ld.so boot.text region is now (silently) failing because the region is
contained within the text LOAD, which is immutable.  So create a new btext
LOAD with flags PF_X|PF_R|PF_OPENBSD_MUTABLE, and place all boot.text objects
in there.  This LOAD must also be page-aligned so it doesn't skip unmapping
some of the object region, previously it was hilariously unaligned.
Similar changes for other architectures coming after more testing.
ok kettenis and guenther seemed to like it also
---

diff --git a/libexec/ld.so/aarch64/ld.script b/libexec/ld.so/aarch64/ld.script
index d0231259a0b..3c4434bb8b4 100644
--- a/libexec/ld.so/aarch64/ld.script
+++ b/libexec/ld.so/aarch64/ld.script
@@ -2,6 +2,7 @@ PHDRS
 {
 	rodata	PT_LOAD FILEHDR PHDRS FLAGS (4);
 	text	PT_LOAD;
+	btext	PT_LOAD FLAGS (0x08000005);
 	data	PT_LOAD;
 	random	PT_OPENBSD_RANDOMIZE;
 	relro	PT_GNU_RELRO;
@@ -22,13 +23,14 @@ SECTIONS
     /* TEXT */
     . = ALIGN(0x10000);
     .text	: { *(.text .text.*) } :text
-    . = ALIGN(0x1000);
     .boot.text	:
     {
+	. = ALIGN(0x1000);
 	boot_text_start = .;
 	*(.boot.text)
+	. = ALIGN(0x1000);
 	boot_text_end = .;
-    } :text
+    } :btext
 
     /* RELRO DATA */
     . = DATA_SEGMENT_ALIGN (0x10000, 0x1000);
diff --git a/libexec/ld.so/amd64/ld.script b/libexec/ld.so/amd64/ld.script
index 5629239dd52..29f4e14d844 100644
--- a/libexec/ld.so/amd64/ld.script
+++ b/libexec/ld.so/amd64/ld.script
@@ -2,6 +2,7 @@ PHDRS
 {
 	rodata	PT_LOAD FILEHDR PHDRS FLAGS (4);
 	text	PT_LOAD;
+	btext	PT_LOAD FLAGS (0x08000005);
 	data	PT_LOAD;
 	random	PT_OPENBSD_RANDOMIZE;
 	relro	PT_GNU_RELRO;
@@ -20,14 +21,15 @@ SECTIONS
     .eh_frame	: { *(.eh_frame) } :rodata
 
     /* TEXT */
-    . = ALIGN(0x100000) + (. & (0x100000 - 1)) +   0;
+    . = ALIGN(0x1000);
     .boot.text	:
     {
+	. = ALIGN(0x1000);
 	boot_text_start = .;
 	*(.boot.text)
+	. = ALIGN(0x1000);
 	boot_text_end = .;
-    } :text =0xcccccccc
-    . = ALIGN(0x1000);
+    } :btext =0xcccccccc
     .text	: { *(.text .text.*) } :text =0xcccccccc
 
     /* RELRO DATA */