net: Real fix for check_params users

OK, last try: 8e4416af45 broke -net socket, ffad4116b9 tried to fix it
but broke error reporting of invalid parameters. So this patch widely
reverts ffad4116b9 again and intead fixes those callers of check_params
that originally suffered from overwritten buffers by using separate
ones.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Mark McLoughlin <markmc@redhat.com>

1 files changed, 14 insertions, 25 deletions

diff --git a/vl.c b/vl.c
index ff438d0903..659e9f7bc5 100644
--- a/vl.c
+++ b/vl.c
@@ -1836,45 +1836,34 @@ int get_param_value(char *buf, int buf_size,
     return 0;
 }
 
-int check_params(const char * const *params, const char *str)
+int check_params(char *buf, int buf_size,
+                 const char * const *params, const char *str)
 {
-    int name_buf_size = 1;
     const char *p;
-    char *name_buf;
-    int i, len;
-    int ret = 0;
-
-    for (i = 0; params[i] != NULL; i++) {
-        len = strlen(params[i]) + 1;
-        if (len > name_buf_size) {
-            name_buf_size = len;
-        }
-    }
-    name_buf = qemu_malloc(name_buf_size);
+    int i;
 
     p = str;
     while (*p != '\0') {
-        p = get_opt_name(name_buf, name_buf_size, p, '=');
+        p = get_opt_name(buf, buf_size, p, '=');
         if (*p != '=') {
-            ret = -1;
-            break;
+            return -1;
         }
         p++;
-        for(i = 0; params[i] != NULL; i++)
-            if (!strcmp(params[i], name_buf))
+        for (i = 0; params[i] != NULL; i++) {
+            if (!strcmp(params[i], buf)) {
                 break;
+            }
+        }
         if (params[i] == NULL) {
-            ret = -1;
-            break;
+            return -1;
         }
         p = get_opt_value(NULL, 0, p);
-        if (*p != ',')
+        if (*p != ',') {
             break;
+        }
         p++;
     }
-
-    qemu_free(name_buf);
-    return ret;
+    return 0;
 }
 
 /***********************************************************/
@@ -2227,7 +2216,7 @@ int drive_init(struct drive_opt *arg, int snapshot, void *opaque)
                                            "cache", "format", "serial", "werror",
                                            NULL };
 
-    if (check_params(params, str) < 0) {
+    if (check_params(buf, sizeof(buf), params, str) < 0) {
          fprintf(stderr, "qemu: unknown parameter '%s' in '%s'\n",
                          buf, str);
          return -1;