Author: kib
Date: Thu Jan 12 15:54:03 2017
New Revision: 311984
URL: https://svnweb.freebsd.org/changeset/base/311984
Log:
For the main binary, postpone enforcing relro read-only protection
until copy relocations are done.
Newer binutils and lld seems to output copy into relro-protected range.
Reported by: Rafael Espц╜ndola via emaste
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Modified:
head/libexec/rtld-elf/rtld.c
Modified: head/libexec/rtld-elf/rtld.c
==============================================================================
--- head/libexec/rtld-elf/rtld.c Thu Jan 12 15:26:23 2017
(r311983)
+++ head/libexec/rtld-elf/rtld.c Thu Jan 12 15:54:03 2017
(r311984)
@@ -103,6 +103,7 @@ static int load_needed_objects(Obj_Entry
static int load_preload_objects(void);
static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int);
static void map_stacks_exec(RtldLockState *);
+static int obj_enforce_relro(Obj_Entry *);
static Obj_Entry *obj_from_addr(const void *);
static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *);
static void objlist_call_init(Objlist *, RtldLockState *);
@@ -617,6 +618,10 @@ _rtld(Elf_Addr *sp, func_ptr_type *exit_
if (do_copy_relocations(obj_main) == -1)
rtld_die();
+ dbg("enforcing main obj relro");
+ if (obj_enforce_relro(obj_main) == -1)
+ rtld_die();
+
if (getenv(_LD("DUMP_REL_POST")) != NULL) {
dump_relocations(obj_main);
exit (0);
@@ -2746,14 +2751,8 @@ relocate_object(Obj_Entry *obj, bool bin
reloc_non_plt(obj, rtldobj, flags | SYMLOOK_IFUNC, lockstate))
return (-1);
- if (obj->relro_size > 0) {
- if (mprotect(obj->relro_page, obj->relro_size,
- PROT_READ) == -1) {
- _rtld_error("%s: Cannot enforce relro protection: %s",
- obj->path, rtld_strerror(errno));
- return (-1);
- }
- }
+ if (!obj->mainprog && obj_enforce_relro(obj) == -1)
+ return (-1);
/*
* Set up the magic number and version in the Obj_Entry. These
@@ -5124,6 +5123,19 @@ _rtld_is_dlopened(void *arg)
return (res);
}
+int
+obj_enforce_relro(Obj_Entry *obj)
+{
+
+ if (obj->relro_size > 0 && mprotect(obj->relro_page, obj->relro_size,
+ PROT_READ) == -1) {
+ _rtld_error("%s: Cannot enforce relro protection: %s",
+ obj->path, rtld_strerror(errno));
+ return (-1);
+ }
+ return (0);
+}
+
static void
map_stacks_exec(RtldLockState *lockstate)
{
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