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[PATCH 1/2] Check IFUNC definition in unrelocated shared library [BZ #20019]
- From: "H.J. Lu" <hongjiu dot lu at intel dot com>
- To: GNU C Library <libc-alpha at sourceware dot org>
- Date: Tue, 4 Oct 2016 11:45:16 -0700
- Subject: [PATCH 1/2] Check IFUNC definition in unrelocated shared library [BZ #20019]
- Authentication-results: sourceware.org; auth=none
- Reply-to: "H.J. Lu" <hjl dot tools at gmail dot com>
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.
Tested on i686 and x86-64. OK for master?
H.J.
---
[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.
---
sysdeps/i386/dl-machine.h | 18 +++++++++++++++++-
sysdeps/x86_64/dl-machine.h | 18 +++++++++++++++++-
2 files changed, 34 insertions(+), 2 deletions(-)
diff --git a/sysdeps/i386/dl-machine.h b/sysdeps/i386/dl-machine.h
index 4e3968a..e5ad0c5 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 c0f0fa1..5c021dc 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)
{
--
2.7.4