Fix infinite loop in check_pf (BZ #12926)

The recvmsg could return 0 under some conditions and cause the
make_request function to be stuck in an infinite loop.

Thank you Jim King <jim.king@simplivity.com> for posting Paul's patch
on the list.

diff --git a/ChangeLog b/ChangeLog
index e40ba1f..73db084 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2014-10-14  Paul Pluzhnikov  <ppluzhnikov@google.com>
+
+       [BZ #12926]
+       * sysdeps/unix/sysv/linux/check_pf.c (make_request): Avoid
+       infinite loop when __recvmsg returns 0.
+
 2014-10-10  Joseph Myers  <joseph@codesourcery.com>
 
        * CANCEL-FCT-WAIVE: Remove file.

diff --git a/NEWS b/NEWS
index accc144..987f306 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -9,7 +9,7 @@ Version 2.21
 
 * The following bugs are resolved with this release:
 
-  6652, 14171, 17266, 17363, 17370, 17371, 17411, 17460.
+  6652, 12926, 14171, 17266, 17363, 17370, 17371, 17411, 17460.
 \f
 Version 2.20
 

diff --git a/sysdeps/unix/sysv/linux/check_pf.c b/sysdeps/unix/sysv/linux/check_pf.c
index c7fd9b0..976f249 100644 (file)
--- a/sysdeps/unix/sysv/linux/check_pf.c
+++ b/sysdeps/unix/sysv/linux/check_pf.c
@@ -180,7 +180,7 @@ make_request (int fd, pid_t pid)
        };
 
       ssize_t read_len = TEMP_FAILURE_RETRY (__recvmsg (fd, &msg, 0));
-      if (read_len < 0)
+      if (read_len <= 0)
        goto out_fail2;
 
       if (msg.msg_flags & MSG_TRUNC)