Turn OFD locks back on with glibc workaround

Resolves: #1274922

2 files changed, 80 insertions, 3 deletions

diff --git a/krb5-1.14.4-ofd-lock-workaround.patch b/krb5-1.14.4-ofd-lock-workaround.patch
new file mode 100644
index 0000000..3786afd
--- /dev/null
+++ b/krb5-1.14.4-ofd-lock-workaround.patch
@@ -0,0 +1,73 @@
+From 65110210b75d38908cdd84cb202cf013ccf6ed0e Mon Sep 17 00:00:00 2001
+From: Greg Hudson <ghudson@mit.edu>
+Date: Sun, 14 Aug 2016 12:08:16 -0400
+Subject: [PATCH] Work around glibc OFD lock bug on 32-bit Linux
+
+A bug in Gnu libc causes OFD locking to fail unpredictably on 32-bit
+Linux, typically leading to deadlocks.  Work around this bug by using
+the fcntl64 system call and struct flock64.
+
+See also: https://sourceware.org/bugzilla/show_bug.cgi?id=20251
+
+ticket: 8474
+target_version: 1.14-next
+tags: pullup
+---
+ src/lib/krb5/os/lock_file.c | 26 ++++++++++++++++++++++++--
+ 1 file changed, 24 insertions(+), 2 deletions(-)
+
+diff --git a/src/lib/krb5/os/lock_file.c b/src/lib/krb5/os/lock_file.c
+index a2f247c..2360c96 100644
+--- a/src/lib/krb5/os/lock_file.c
++++ b/src/lib/krb5/os/lock_file.c
+@@ -43,7 +43,29 @@
+ 
+ #if defined(HAVE_FCNTL_H) && defined(F_SETLKW) && defined(F_RDLCK)
+ #define POSIX_FILE_LOCKS
++
++/*
++ * Gnu libc bug 20251, currently unfixed, breaks OFD lock support on
++ * 32-bit platforms.  Work around this bug by explicitly using the
++ * fcntl64 system call and struct flock64.
++ */
++#if defined(__linux__) && __WORDSIZE == 32
++#include <sys/syscall.h>
++#ifdef SYS_fcntl64
++#define USE_FCNTL64
+ #endif
++#endif
++#ifdef USE_FCNTL64
++/* Use the fcntl64 system call and struct flock64.  (Gnu libc does not
++ * define a fcntl64() function, so we must use syscall().) */
++#define fcntl(fd, cmd, arg) syscall(SYS_fcntl64, fd, cmd, arg)
++typedef struct flock64 fcntl_lock_st;
++#else
++/* Use regular fcntl() and struct flock. */
++typedef struct flock fcntl_lock_st;
++#endif
++
++#endif /* defined(HAVE_FCNTL_H) && defined(F_SETLKW) && defined(F_RDLCK) */
+ 
+ #ifdef HAVE_FLOCK
+ #ifndef sysvimp
+@@ -66,7 +88,7 @@
+  * older kernel than we were built with.
+  */
+ static int
+-ofdlock(int fd, int cmd, struct flock *lock_arg)
++ofdlock(int fd, int cmd, fcntl_lock_st *lock_arg)
+ {
+ #ifdef F_OFD_SETLKW
+     int st, ofdcmd;
+@@ -89,7 +111,7 @@ krb5_lock_file(krb5_context context, int fd, int mode)
+     krb5_error_code     retval = 0;
+ #ifdef POSIX_FILE_LOCKS
+     int lock_cmd = F_SETLKW;
+-    struct flock lock_arg = { 0 };
++    fcntl_lock_st lock_arg = { 0 };
+ #endif
+ 
+     switch (mode & ~KRB5_LOCKMODE_DONTBLOCK) {
+-- 
+2.8.1
+
diff --git a/krb5.spec b/krb5.spec
index 440c059..6abb731 100644
--- a/krb5.spec
+++ b/krb5.spec
@@ -13,7 +13,7 @@
 Summary: The Kerberos network authentication system
 Name: krb5
 Version: 1.14.3
-Release: 4%{?dist}
+Release: 5%{?dist}
 # - Maybe we should explode from the now-available-to-everybody tarball instead?
 # http://web.mit.edu/kerberos/dist/krb5/1.13/krb5-1.13.2-signed.tar
 # - The sources below are stored in a lookaside cache. Upload with
@@ -56,7 +56,7 @@ Patch71: krb5-1.13-dirsrv-accountlock.patch
 Patch86: krb5-1.9-debuginfo.patch
 Patch129: krb5-1.11-run_user_0.patch
 Patch134: krb5-1.11-kpasswdtest.patch
-Patch148: krb5-disable_ofd_locks.patch
+Patch148: krb5-1.14.4-ofd-lock-workaround.patch
 Patch150: krb5-acquire_cred_interposer.patch
 Patch153: krb5-1.14.1-log_file_permissions.patch
 
@@ -264,7 +264,7 @@ ln NOTICE LICENSE
 
 %patch134 -p1 -b .kpasswdtest
 
-%patch148 -p1 -b .disable_ofd_locks
+%patch148 -p1 -b .ofd-lock-workaround
 
 %patch150 -p1 -b .fix_interposer
 %patch153 -p1 -b .log_file_permissions
@@ -742,6 +742,10 @@ exit 0
 %{_libdir}/libkadm5srv_mit.so.*
 
 %changelog
+* Mon Aug 15 2016 Robbie Harwood <rharwood@redhat.com> - 1.14.3-5
+- Turn OFD locks back on with glibc workaround
+- Resolves: #1274922
+
 * Wed Aug 10 2016 Robbie Harwood <rharwood@redhat.com> - 1.14.3-4
 - Fix use of KKDCPP with SNI
 - Resolves: #1365027