fix rejection of dns responses with pointers past 512 byte offset

[musl] / src / network / res_mkquery.c

diff --git a/src/network/res_mkquery.c b/src/network/res_mkquery.c
index 6fa04a5..614bf78 100644 (file)
--- a/src/network/res_mkquery.c
+++ b/src/network/res_mkquery.c
@@ -13,6 +13,7 @@ int __res_mkquery(int op, const char *dname, int class, int type,
        int n;
 
        if (l && dname[l-1]=='.') l--;
+       if (l && dname[l-1]=='.') return -1;
        n = 17+l+!!l;
        if (l>253 || buflen<n || op>15u || class>255u || type>255u)
                return -1;
@@ -20,6 +21,7 @@ int __res_mkquery(int op, const char *dname, int class, int type,
        /* Construct query template - ID will be filled later */
        memset(q, 0, n);
        q[2] = op*8 + 1;
+       q[3] = 32; /* AD */
        q[5] = 1;
        memcpy((char *)q+13, dname, l);
        for (i=13; q[i]; i=j+1) {