cmd/link: don't emit PAX_FLAGS segment on Linux

We started emitting this segment in 2012 in CL 6326054 for #47. It disabled three kinds of protection: mprotect, randexec, and emutramp. The randexec protection was deprecated some time ago, replaced by PIE. The emutramp and mprotect protection was because we used to rely on being able to create writable executable memory to implement function closures, but that is not true since https://go.dev/s/go11func was implemented. Change-Id: I5e3a5279d76d642b0423d26195b891479a235763 Reviewed-on: https://go-review.googlesource.com/c/go/+/471199 Run-TryBot: Ian Lance Taylor <[email protected]> Auto-Submit: Ian Lance Taylor <[email protected]> Reviewed-by: Ian Lance Taylor <[email protected]> TryBot-Result: Gopher Robot <[email protected]> Reviewed-by: Cherry Mui <[email protected]>
tailscale · Feb 25, 2023 · ffb07d0 · ffb07d0
1 parent 203e59a
commit ffb07d0
Showing 1 changed file with 1 addition and 11 deletions.
diff --git a/src/cmd/link/internal/ld/elf.go b/src/cmd/link/internal/ld/elf.go
@@ -2135,25 +2135,15 @@ func asmbElf(ctxt *Link) {
 		}
 	}
 
-	if ctxt.HeadType == objabi.Hlinux {
+	if ctxt.HeadType == objabi.Hlinux || ctxt.HeadType == objabi.Hfreebsd {
 		ph := newElfPhdr()
 		ph.Type = elf.PT_GNU_STACK
 		ph.Flags = elf.PF_W + elf.PF_R
 		ph.Align = uint64(ctxt.Arch.RegSize)
-
-		ph = newElfPhdr()
-		ph.Type = elf.PT_PAX_FLAGS
-		ph.Flags = 0x2a00 // mprotect, randexec, emutramp disabled
-		ph.Align = uint64(ctxt.Arch.RegSize)
 	} else if ctxt.HeadType == objabi.Hsolaris {
 		ph := newElfPhdr()
 		ph.Type = elf.PT_SUNWSTACK
 		ph.Flags = elf.PF_W + elf.PF_R
-	} else if ctxt.HeadType == objabi.Hfreebsd {
-		ph := newElfPhdr()
-		ph.Type = elf.PT_GNU_STACK
-		ph.Flags = elf.PF_W + elf.PF_R
-		ph.Align = uint64(ctxt.Arch.RegSize)
 	}
 
 elfobj: