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.

2 files changed, 26 insertions, 2 deletions

diff --git a/misc/mntent_r.c b/misc/mntent_r.c
index 152a9a2ea5..615987347a 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 802b56e437..876c89f8ed 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;
 }