From: H.J. Lu <hjl.tools@gmail.com>
Date: Fri, 28 Oct 2016 16:11:55 +0000 (-0700)
Subject: Check IFUNC definition in unrelocated shared library [BZ #20019]
X-Git-Tag: glibc-2.25~367
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0e6d3adc60d8073397af6a320e594d98d7fbedde;p=thirdparty%2Fglibc.git

Check IFUNC definition in unrelocated shared library [BZ #20019]

Calling an IFUNC function defined in unrelocated shared library may
lead to segfault.  This patch issues an error message to request
relinking the shared library if it references IFUNC function defined
in the unrelocated shared library.

	[BZ #20019]
	* sysdeps/i386/dl-machine.h (elf_machine_rel): Check IFUNC
	definition in unrelocated shared library.
	* sysdeps/x86_64/dl-machine.h (elf_machine_rela): Likewise.
---

diff --git a/ChangeLog b/ChangeLog
index b5626ed5cad..995720ec690 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2016-10-28  H.J. Lu  <hongjiu.lu@intel.com>
+
+	[BZ #20019]
+	* sysdeps/i386/dl-machine.h (elf_machine_rel): Check IFUNC
+	definition in unrelocated shared library.
+	* sysdeps/x86_64/dl-machine.h (elf_machine_rela): Likewise.
+
 2016-10-28  Florian Weimer  <fweimer@redhat.com>
 
 	[BZ #20729]
diff --git a/sysdeps/i386/dl-machine.h b/sysdeps/i386/dl-machine.h
index 4e3968a8aaa..e5ad0c513d2 100644
--- a/sysdeps/i386/dl-machine.h
+++ b/sysdeps/i386/dl-machine.h
@@ -321,7 +321,23 @@ elf_machine_rel (struct link_map *map, const Elf32_Rel *reloc,
 			       0)
 	  && __builtin_expect (sym->st_shndx != SHN_UNDEF, 1)
 	  && __builtin_expect (!skip_ifunc, 1))
-	value = ((Elf32_Addr (*) (void)) value) ();
+	{
+# ifndef RTLD_BOOTSTRAP
+	  if (sym_map != map
+	      && sym_map->l_type != lt_executable
+	      && !sym_map->l_relocated)
+	    {
+	      const char *strtab
+		= (const char *) D_PTR (map, l_info[DT_STRTAB]);
+	      _dl_fatal_printf ("\
+%s: Relink `%s' with `%s' for IFUNC symbol `%s'\n",
+				RTLD_PROGNAME, map->l_name,
+				sym_map->l_name,
+				strtab + refsym->st_name);
+	    }
+# endif
+	  value = ((Elf32_Addr (*) (void)) value) ();
+	}
 
       switch (r_type)
 	{
diff --git a/sysdeps/x86_64/dl-machine.h b/sysdeps/x86_64/dl-machine.h
index c0f0fa16a23..5c021dcf992 100644
--- a/sysdeps/x86_64/dl-machine.h
+++ b/sysdeps/x86_64/dl-machine.h
@@ -331,7 +331,23 @@ elf_machine_rela (struct link_map *map, const ElfW(Rela) *reloc,
 			       0)
 	  && __builtin_expect (sym->st_shndx != SHN_UNDEF, 1)
 	  && __builtin_expect (!skip_ifunc, 1))
-	value = ((ElfW(Addr) (*) (void)) value) ();
+	{
+# ifndef RTLD_BOOTSTRAP
+	  if (sym_map != map
+	      && sym_map->l_type != lt_executable
+	      && !sym_map->l_relocated)
+	    {
+	      const char *strtab
+		= (const char *) D_PTR (map, l_info[DT_STRTAB]);
+	      _dl_fatal_printf ("\
+%s: Relink `%s' with `%s' for IFUNC symbol `%s'\n",
+				RTLD_PROGNAME, map->l_name,
+				sym_map->l_name,
+				strtab + refsym->st_name);
+	    }
+# endif
+	  value = ((ElfW(Addr) (*) (void)) value) ();
+	}
 
       switch (r_type)
 	{