From e0db7fae8728ef47b8cd020d7fe993069c3e61d0 Mon Sep 17 00:00:00 2001
From: Shenghou Ma <minux.ma@gmail.com>
Date: Fri, 3 May 2013 16:33:21 +0800
Subject: [PATCH] cmd/ld: add .note.GNU-stack section for external linking
 Fixes #5392.

R=iant, r
CC=golang-dev
https://golang.org/cl/9119043
---
 src/cmd/ld/elf.c                | 9 ++++++++-
 src/pkg/runtime/cgo/gcc_386.S   | 3 +++
 src/pkg/runtime/cgo/gcc_amd64.S | 4 ++++
 src/pkg/runtime/cgo/gcc_arm.S   | 3 +++
 4 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/cmd/ld/elf.c b/src/cmd/ld/elf.c
index 0d1b712ce8c..daef5793ffd 100644
--- a/src/cmd/ld/elf.c
+++ b/src/cmd/ld/elf.c
@@ -930,6 +930,8 @@ doelf(void)
 			addstring(shstrtab, ".rel.noptrdata");
 			addstring(shstrtab, ".rel.data");
 		}
+		// add a .note.GNU-stack section to mark the stack as non-executable
+		addstring(shstrtab, ".note.GNU-stack");
 	}
 
 	if(!debug['s']) {
@@ -1403,8 +1405,13 @@ elfobj:
 			elfshreloc(sect);
 		for(sect=segdata.sect; sect!=nil; sect=sect->next)
 			elfshreloc(sect);
+		// add a .note.GNU-stack section to mark the stack as non-executable
+		sh = elfshname(".note.GNU-stack");
+		sh->type = SHT_PROGBITS;
+		sh->addralign = 1;
+		sh->flags = 0;
 	}
-		
+
 	if(!debug['s']) {
 		sh = elfshname(".symtab");
 		sh->type = SHT_SYMTAB;
diff --git a/src/pkg/runtime/cgo/gcc_386.S b/src/pkg/runtime/cgo/gcc_386.S
index 94ba5842f19..bf4142793c5 100644
--- a/src/pkg/runtime/cgo/gcc_386.S
+++ b/src/pkg/runtime/cgo/gcc_386.S
@@ -40,3 +40,6 @@ EXT(__stack_chk_fail_local):
 1:
 	jmp 1b
 
+#ifdef __ELF__
+.section .note.GNU-stack,"",@progbits
+#endif
diff --git a/src/pkg/runtime/cgo/gcc_amd64.S b/src/pkg/runtime/cgo/gcc_amd64.S
index 81b270195d1..32d0200cf7b 100644
--- a/src/pkg/runtime/cgo/gcc_amd64.S
+++ b/src/pkg/runtime/cgo/gcc_amd64.S
@@ -42,3 +42,7 @@ EXT(crosscall_amd64):
 	popq %rbp
 	popq %rbx
 	ret
+
+#ifdef __ELF__
+.section .note.GNU-stack,"",@progbits
+#endif
diff --git a/src/pkg/runtime/cgo/gcc_arm.S b/src/pkg/runtime/cgo/gcc_arm.S
index 809fcb9a06e..3bc5bd338f8 100644
--- a/src/pkg/runtime/cgo/gcc_arm.S
+++ b/src/pkg/runtime/cgo/gcc_arm.S
@@ -34,3 +34,6 @@ EXT(__stack_chk_fail_local):
 1:
 	b 1b
 
+#ifdef __ELF__
+.section .note.GNU-stack,"",@progbits
+#endif