svn commit: r361725 - head/libexec/rtld-elf
Konstantin Belousov
kib at FreeBSD.org
Tue Jun 2 16:20:59 UTC 2020
Author: kib
Date: Tue Jun 2 16:20:58 2020
New Revision: 361725
URL: https://svnweb.freebsd.org/changeset/base/361725
Log:
Do not allow to load ET_DYN object with DF_1_PIE flag set.
Linkers are supposed to mark PIE binaries with DF_1_PIE, such binary
cannot be correctly and usefully loaded neither by dlopen(3) nor as a
dependency of other object. For instance, we cannot do anything
useful with COPY relocations, among other things.
Glibc already added similar restriction.
Requested and reviewed by: emaste
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D25086
Modified:
head/libexec/rtld-elf/rtld.c
head/libexec/rtld-elf/rtld.h
Modified: head/libexec/rtld-elf/rtld.c
==============================================================================
--- head/libexec/rtld-elf/rtld.c Tue Jun 2 12:23:04 2020 (r361724)
+++ head/libexec/rtld-elf/rtld.c Tue Jun 2 16:20:58 2020 (r361725)
@@ -1370,6 +1370,8 @@ digest_dynamic1(Obj_Entry *obj, int early, const Elf_D
obj->z_interpose = true;
if (dynp->d_un.d_val & DF_1_NODEFLIB)
obj->z_nodeflib = true;
+ if (dynp->d_un.d_val & DF_1_PIE)
+ obj->z_pie = true;
break;
default:
@@ -2580,6 +2582,10 @@ do_load_object(int fd, const char *name, char *path, s
obj->path = path;
if (!digest_dynamic(obj, 0))
goto errp;
+ if (obj->z_pie) {
+ _rtld_error("Cannot load PIE binary %s as dso", obj->path);
+ goto errp;
+ }
dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path,
obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount);
if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) ==
Modified: head/libexec/rtld-elf/rtld.h
==============================================================================
--- head/libexec/rtld-elf/rtld.h Tue Jun 2 12:23:04 2020 (r361724)
+++ head/libexec/rtld-elf/rtld.h Tue Jun 2 16:20:58 2020 (r361725)
@@ -257,6 +257,7 @@ typedef struct Struct_Obj_Entry {
bool z_interpose : 1; /* Interpose all objects but main */
bool z_nodeflib : 1; /* Don't search default library path */
bool z_global : 1; /* Make the object global */
+ bool z_pie : 1; /* Object proclaimed itself PIE executable */
bool static_tls : 1; /* Needs static TLS allocation */
bool static_tls_copied : 1; /* Needs static TLS copying */
bool ref_nodel : 1; /* Refcount increased to prevent dlclose */
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