mdopen: fix gcc 8.1 string overflow error

We already cut symlinks longer than 1000, so rely on this calling
readlink and error out if we are able to read more than 1000 bytes.

Signed-off-by: Jes Sorensen <jsorensen@fb.com>

diff --git a/mdopen.c b/mdopen.c
index 4ec13f5eb5979a66234976115e1d466f7e005d76..98c54e433a5df1986af0e12dadb996b0f4f0836b 100644 (file)
--- a/mdopen.c
+++ b/mdopen.c
@@ -44,7 +44,7 @@ void make_parts(char *dev, int cnt)
        int nlen = strlen(dev) + 20;
        char *name;
        int dig = isdigit(dev[strlen(dev)-1]);
-       char orig[1024];
+       char orig[1001];
        char sym[1024];
        int err;
 
@@ -58,8 +58,10 @@ void make_parts(char *dev, int cnt)
                minor_num = minor(stb.st_rdev);
                odig = -1;
        } else if (S_ISLNK(stb.st_mode)) {
-               int len = readlink(dev, orig, sizeof(orig));
-               if (len < 0 || len > 1000)
+               int len;
+
+               len = readlink(dev, orig, sizeof(orig));
+               if (len < 0 || len >= (int)sizeof(orig))
                        return;
                orig[len] = 0;
                odig = isdigit(orig[len-1]);