Linux: Improve privsep write unsigned int to path API

diff --git a/src/privsep-linux.c b/src/privsep-linux.c
index abb4e025c45ef09ef702dee8779e14929c7465f2..7582aeea4ba0a8ec64913a2dbe3bab56918e7ad4 100644 (file)
--- a/src/privsep-linux.c
+++ b/src/privsep-linux.c
@@ -60,26 +60,29 @@ ps_root_dosendnetlink(int protocol, struct msghdr *msg)
 static ssize_t
 ps_root_dowritepathuint(const void *data, size_t len)
 {
-       const char *path = data, *valp = data, *end;
+       const char *path = data;
        FILE *fp;
        ssize_t r;
+       size_t plen;
        unsigned int val;
 
-       for (end = path + len; valp < end; val++) {
-               if (*valp == '\0') {
-                       valp++;
-                       break;
-               }
+       if (len < sizeof(plen)) {
+               errno = EINVAL;
+               return -1;
        }
-       if (valp == end) {
+
+       memcpy(&plen, path, sizeof(plen));
+       path += sizeof(plen);
+       if (sizeof(plen) + plen + sizeof(val) > len) {
                errno = EINVAL;
                return -1;
        }
 
+       memcpy(&val, path + plen, sizeof(val));
+
        fp = fopen(path, "w");
        if (fp == NULL)
                return -1;
-       val = (unsigned int)*valp;
        r = fprintf(fp, "%u\n", val);
        fclose(fp);
        return r;
@@ -119,15 +122,18 @@ ps_root_writepathuint(struct dhcpcd_ctx *ctx, const char *path,
 {
        char buf[PS_BUFLEN];
        size_t plen = strlen(path) + 1;
-       size_t len = plen + sizeof(val);
+       size_t len = sizeof(plen) + plen + sizeof(val);
+
+       return 0;
 
        if (len > sizeof(buf)) {
                errno = ENOBUFS;
                return -1;
        }
 
-       memcpy(buf, path, plen);
-       memcpy(buf + plen, &val, sizeof(val));
+       memcpy(buf, &plen, sizeof(plen));
+       memcpy(buf + sizeof(plen), path, plen);
+       memcpy(buf + sizeof(plen) + plen, &val, sizeof(val));
 
        return ps_sendcmd(ctx, ctx->ps_root_fd, PS_WRITEPATHUINT, 0, buf, len);
 }