[bug-patch] [PATCH] terminate readlink string

[Tobias Stoeckmann]

The function readlink does not nul terminate its result string.
safe_readlink is a wrapper for readlinkat, which has the same
behaviour.  Therefore, explicitly set '\0' and reserve one byte for it.
---
 src/util.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/util.c b/src/util.c
index 82a7e37..4bf969a 100644
--- a/src/util.c
+++ b/src/util.c
@@ -611,9 +611,11 @@ copy_file (char const *from, char const *to, struct stat 
*tost,
   if (S_ISLNK (mode))
     {
       char *buffer = xmalloc (PATH_MAX);
+      ssize_t r;
 
-      if (safe_readlink (from, buffer, PATH_MAX) < 0)
+      if ((r = safe_readlink (from, buffer, PATH_MAX - 1)) < 0)
        pfatal ("Can't read %s %s", "symbolic link", from);
+      buffer[r] = '\0';
       if (safe_symlink (buffer, to) != 0)
        pfatal ("Can't create %s %s", "symbolic link", to);
       if (tost && safe_lstat (to, tost) != 0)
-- 
2.4.5