Resolves: #1326903

Fix fork redirection in libpthread

glibc-rh1326903.patch

@@ -0,0 +1,73 @@
+commit f06f3f05b48c72e2c9b0fa78671f94fd22d67da8
+Author: Florian Weimer <fweimer@redhat.com>
+Date:   Wed Jun 1 07:14:42 2016 +0200
+
+    fork in libpthread cannot use IFUNC resolver [BZ #19861]
+    
+    This commit only addresses the fork case, the vfork case has to be a
+    tail call, which is why the generic code needs an IFUNC resolver
+    there.
+
+diff --git a/nptl/pt-fork.c b/nptl/pt-fork.c
+index b65d6b4..db9b61d 100644
+--- a/nptl/pt-fork.c
++++ b/nptl/pt-fork.c
+@@ -25,33 +25,14 @@
+    the historical ABI requires it.  For static linking, there is no need to
+    provide anything here--the libc version will be linked in.  For shared
+    library ABI compatibility, there must be __fork and fork symbols in
+-   libpthread.so; so we define them using IFUNC to redirect to the libc
+-   function.  */
++   libpthread.so.
+ 
+-#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_22)
+-
+-# if HAVE_IFUNC
+-
+-static __typeof (fork) *
+-__attribute__ ((used))
+-fork_resolve (void)
+-{
+-  return &__libc_fork;
+-}
++   With an IFUNC resolver, it would be possible to avoid the
++   indirection, but the IFUNC resolver might run before the
++   __libc_fork symbol has been relocated, in which case the IFUNC
++   resolver would not be able to provide the correct address.  */
+ 
+-#  ifdef HAVE_ASM_SET_DIRECTIVE
+-#   define DEFINE_FORK(name) \
+-  asm (".set " #name ", fork_resolve\n" \
+-       ".globl " #name "\n" \
+-       ".type " #name ", %gnu_indirect_function");
+-#  else
+-#   define DEFINE_FORK(name) \
+-  asm (#name " = fork_resolve\n" \
+-       ".globl " #name "\n" \
+-       ".type " #name ", %gnu_indirect_function");
+-#  endif
+-
+-# else  /* !HAVE_IFUNC */
++#if SHLIB_COMPAT (libpthread, GLIBC_2_0, GLIBC_2_22)
+ 
+ static pid_t __attribute__ ((used))
+ fork_compat (void)
+@@ -59,14 +40,10 @@ fork_compat (void)
+   return __libc_fork ();
+ }
+ 
+-# define DEFINE_FORK(name) strong_alias (fork_compat, name)
+-
+-# endif  /* HAVE_IFUNC */
+-
+-DEFINE_FORK (fork_ifunc)
+-compat_symbol (libpthread, fork_ifunc, fork, GLIBC_2_0);
++strong_alias (fork_compat, fork_alias)
++compat_symbol (libpthread, fork_alias, fork, GLIBC_2_0);
+ 
+-DEFINE_FORK (__fork_ifunc)
+-compat_symbol (libpthread, __fork_ifunc, __fork, GLIBC_2_0);
++strong_alias (fork_compat, __fork_alias)
++compat_symbol (libpthread, __fork_alias, __fork, GLIBC_2_0);
+ 
+ #endif

glibc.spec

@@ -268,6 +268,7 @@ Patch1047: glibc-rh1330888.patch
 Patch1048: glibc-rh1204521.patch
 Patch1049: glibc-rh1282011.patch
 Patch1050: glibc-rh1337140.patch
+Patch1051: glibc-rh1326903.patch
 
 ##############################################################################
 #
@@ -735,6 +736,7 @@ microbenchmark tests on the system.
 %patch1048 -p1
 %patch1049 -p1
 %patch1050 -p1
+%patch1051 -p1
 %patch0059 -p1
 
 ##############################################################################
@@ -1957,6 +1959,7 @@ rm -f *.filelist*
 %changelog
 * Thu Jun  2 2016 Florian Weimer <fweimer@redhat.com> - 2.22-17
 - CVE-2016-4429: stack overflow in Sun RPC clntudp_call (#1337140)
+- Fix fork redirection in libpthread (#1326903)
 
 * Wed May 11 2016 Florian Weimer <fweimer@redhat.com> - 2.22-16
 - Back out dlsym (RTLD_NEXT)/dlerror change (#1333945)