[glibc] hurd: Avoid overzealous shared objects constraints

[glibc] hurd: Avoid overzealous shared objects constraints

[Samuel Thibault]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=8c0727af63198661c0ae3641a9d66609021754a7

commit 8c0727af63198661c0ae3641a9d66609021754a7
Author: Samuel Thibault <samuel.thibault@ens-lyon.org>
Date:   Fri Dec 31 18:17:40 2021 +0100

    hurd: Avoid overzealous shared objects constraints
    
    407765e9f24f ("hurd: Fix ELF_MACHINE_USER_ADDRESS_MASK value") switched
    ELF_MACHINE_USER_ADDRESS_MASK from 0xf8000000UL to 0xf0000000UL to let
    libraries etc. get loaded at 0x08000000. But
    ELF_MACHINE_USER_ADDRESS_MASK is actually only meaningful for the main
    program anyway, so keep it at 0xf8000000UL to prevent the program loader
    from putting ld.so beyond 0x08000000. And conversely, drop the use of
    ELF_MACHINE_USER_ADDRESS_MASK for shared objects, which don't need any
    constraints since the program will have already be loaded by then.

Diff:
---
 sysdeps/i386/dl-machine.h     | 2 +-
 sysdeps/mach/hurd/dl-sysdep.c | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/sysdeps/i386/dl-machine.h b/sysdeps/i386/dl-machine.h
index 2f0dbc27a9..b5a5dd0983 100644
--- a/sysdeps/i386/dl-machine.h
+++ b/sysdeps/i386/dl-machine.h
@@ -117,7 +117,7 @@ elf_machine_runtime_setup (struct link_map *l, struct r_scope_elem *scope[],
 
 /* Mask identifying addresses reserved for the user program,
    where the dynamic linker should not map anything.  */
-#define ELF_MACHINE_USER_ADDRESS_MASK	0xf0000000UL
+#define ELF_MACHINE_USER_ADDRESS_MASK	0xf8000000UL
 
 /* Initial entry point code for the dynamic linker.
    The C function `_dl_start' is the real entry point;
diff --git a/sysdeps/mach/hurd/dl-sysdep.c b/sysdeps/mach/hurd/dl-sysdep.c
index 968a58f668..b1a151abc1 100644
--- a/sysdeps/mach/hurd/dl-sysdep.c
+++ b/sysdeps/mach/hurd/dl-sysdep.c
@@ -476,7 +476,7 @@ __mmap (void *addr, size_t len, int prot, int flags, int fd, off_t offset)
 
   mapaddr = (vm_address_t) addr;
   err = __vm_map (__mach_task_self (),
-		  &mapaddr, (vm_size_t) len, ELF_MACHINE_USER_ADDRESS_MASK,
+		  &mapaddr, (vm_size_t) len, 0,
 		  !(flags & MAP_FIXED),
 		  memobj_rd,
 		  (vm_offset_t) offset,
@@ -491,7 +491,7 @@ __mmap (void *addr, size_t len, int prot, int flags, int fd, off_t offset)
       if (! err)
 	err = __vm_map (__mach_task_self (),
 			&mapaddr, (vm_size_t) len,
-			ELF_MACHINE_USER_ADDRESS_MASK,
+			0,
 			!(flags & MAP_FIXED),
 			memobj_rd, (vm_offset_t) offset,
 			flags & (MAP_COPY|MAP_PRIVATE),