[v3,BZ,#17273] fix incorrect mount table entry parsing in __getmntent_r()

From fb87ee96d7dd0714d52004e4676629f8d9db732f Mon Sep 17 00:00:00 2001
From: "Vladimir A. Nazarenko" <naszar@ya.ru>
Date: Tue, 6 Jan 2015 19:19:44 -0800
Subject: [PATCH] Fix incorrect mount table entry parsing in __getmntent_r

When mount entry contains only four fields and have more then one space or
tab at the and, mp.mnt_freq and mp.mnt_passno will be set to some specific
values as side effect from parsing of previus mount entry. It is because
sscanf(""," %d %d ", &a, &b) returns -1, but this case is unprocessed.
Values of mp.mnt_freq and  mp.mnt_passno stays unchanged. This patch is
attempt to fix described issue by removing trailing tabs and spaces.
---
 ChangeLog         |  8 ++++++++
 NEWS              | 14 +++++++-------
 misc/mntent_r.c   |  6 +++++-
 misc/tst-mntent.c | 22 +++++++++++++++++++++-
 4 files changed, 41 insertions(+), 9 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index b5aa6e5..9ca4f27 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@ 
+2015-01-06  Vladimir A. Nazarenko  <naszar@ya.ru>
+
+.	[BZ #17273]
+	* misc/mntent_r.c (__getmntent_r): Cut off trailing spaces
+	and tabs from buffer before parsing fstab entry.
+	* misc/tst-mntent.c (main): Add test for mount entry with
+	trailing spaces and tabs.
+
 2015-01-06  Joseph Myers  <joseph@codesourcery.com>
 
 	[BZ #17748]
diff --git a/NEWS b/NEWS
index acb611a..8582885 100644
--- a/NEWS
+++ b/NEWS
@@ -11,13 +11,13 @@  Version 2.21
 
   6652, 10672, 12847, 12926, 13862, 14132, 14138, 14171, 14498, 15215,
   15884, 16191, 16469, 16617, 16619, 16657, 16740, 16857, 17192, 17266,
-  17344, 17363, 17370, 17371, 17411, 17460, 17475, 17485, 17501, 17506,
-  17508, 17522, 17555, 17570, 17571, 17572, 17573, 17574, 17581, 17582,
-  17583, 17584, 17585, 17589, 17594, 17601, 17608, 17616, 17625, 17630,
-  17633, 17634, 17635, 17647, 17653, 17657, 17664, 17665, 17668, 17682,
-  17717, 17719, 17722, 17723, 17724, 17725, 17732, 17733, 17744, 17745,
-  17746, 17747, 17775, 17777, 17780, 17781, 17782, 17793, 17796, 17797,
-  17806
+  17273, 17344, 17363, 17370, 17371, 17411, 17460, 17475, 17485, 17501,
+  17506, 17508, 17522, 17555, 17570, 17571, 17572, 17573, 17574, 17581,
+  17582, 17583, 17584, 17585, 17589, 17594, 17601, 17608, 17616, 17625,
+  17630, 17633, 17634, 17635, 17647, 17653, 17657, 17664, 17665, 17668,
+  17682, 17717, 17719, 17722, 17723, 17724, 17725, 17732, 17733, 17744,
+  17745, 17746, 17747, 17775, 17777, 17780, 17781, 17782, 17793, 17796,
+  17797, 17806
 
 * i386 memcpy functions optimized with SSE2 unaligned load/store.
 
diff --git a/misc/mntent_r.c b/misc/mntent_r.c
index 152a9a2..6159873 100644
--- a/misc/mntent_r.c
+++ b/misc/mntent_r.c
@@ -135,7 +135,11 @@  __getmntent_r (FILE *stream, struct mntent *mp, char *buffer, int bufsiz)
 
       end_ptr = strchr (buffer, '\n');
       if (end_ptr != NULL)	/* chop newline */
-	*end_ptr = '\0';
+	{
+	  while (end_ptr[-1] == ' ' || end_ptr[-1] == '\t')
+            end_ptr--;
+	  *end_ptr = '\0';
+	}
       else
 	{
 	  /* Not the whole line was read.  Do it now but forget it.  */
diff --git a/misc/tst-mntent.c b/misc/tst-mntent.c
index 802b56e..876c89f 100644
--- a/misc/tst-mntent.c
+++ b/misc/tst-mntent.c
@@ -73,7 +73,27 @@  main (int argc, char *argv[])
 	  puts ("Error while reading written entry back in");
 	  result = 1;
 	}
-    }
+
+      /* Part III: Entry with whitespaces at the end of a line. */
+      rewind (fp);
+
+      fputs ("/foo\\040dir /bar\\040dir auto bind \t \n", fp);
+
+      rewind (fp);
+
+      mnt = getmntent (fp);
+
+      if (strcmp (mnt->mnt_fsname, "/foo dir") != 0
+	  || strcmp (mnt->mnt_dir, "/bar dir") != 0
+	  || strcmp (mnt->mnt_type, "auto") != 0
+	  || strcmp (mnt->mnt_opts, "bind") != 0
+	  || mnt->mnt_freq != 0
+	  || mnt->mnt_passno != 0)
+	{
+	  puts ("Error while reading entry with trailing whitespaces");
+	  result = 1;
+	}
+   }
 
   return result;
 }
-- 
1.9.3