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

["Vladimir A. Nazarenko" <naszar at ya dot ru>]

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.

	[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.
---
 misc/mntent_r.c   |  6 +++++-
 misc/tst-mntent.c | 22 +++++++++++++++++++++-
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/misc/mntent_r.c b/misc/mntent_r.c
index e68ec8e..e0a0b9d 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;
 }
-- 
2.1.1