confile_utils: simplify lxc_config_net_hwaddr

In addition to the memory corruption fixed in ee3e84df78424d26fc6c90862fbe0fa92a686b0d,
this function was also performing invalid memory accesses for the following inputs:
- `lxc.net`
- `lxc.net.`
- `lxc.net.0.`
- `lxc.network`
- `lxc.network.0.`

Signed-off-by: Felix Abecassis <fabecassis@nvidia.com>

diff --git a/src/lxc/confile_utils.c b/src/lxc/confile_utils.c
index 50f42ef8c482e4507c0cf45fab6cf320be6c72f4..c2901116ca0e1094f82d8d8fba159ff2588db39c 100644 (file)
--- a/src/lxc/confile_utils.c
+++ b/src/lxc/confile_utils.c
@@ -545,63 +545,18 @@ int rand_complete_hwaddr(char *hwaddr)
 
 bool lxc_config_net_hwaddr(const char *line)
 {
-       char *copy, *p;
+       unsigned index;
+       char tmp[7];
 
        if (strncmp(line, "lxc.net", 7) != 0)
                return false;
-       if (strncmp(line, "lxc.network.hwaddr", 18) == 0)
-               return true;
-
-       /* We have to dup the line, if line is something like
-        * "lxc.net.[i].xxx = xxxxx ", we need to remove
-        * '[i]' and compare its key with 'lxc.net.hwaddr'*/
-       copy = strdup(line);
-       if (!copy) {
-               SYSERROR("failed to allocate memory");
-               return false;
-       }
-       if (*(copy + 8) >= '0' && *(copy + 8) <= '9') {
-               p = strchr(copy + 8, '.');
-               if (!p) {
-                       free(copy);
-                       return false;
-               }
-               /* strlen("hwaddr") = 6 */
-               if (strlen(p + 1) >= 6)
-                        memmove(copy + 8, p + 1, 6);
-               copy[8 + 6] = '\0';
-       }
-       if (strncmp(copy, "lxc.net.hwaddr", 14) == 0) {
-               free(copy);
+       if (strncmp(line, "lxc.net.hwaddr", 14) == 0)
                return true;
-       }
-       free(copy);
-
-       /* We have to dup the line second time, if line is something like
-        * "lxc.network.[i].xxx = xxxxx ", we need to remove
-        * '[i]' and compare its key with 'lxc.network.hwaddr'*/
-       copy = strdup(line);
-       if (!copy) {
-               SYSERROR("failed to allocate memory");
-               return false;
-       }
-       if (*(copy + 12) >= '0' && *(copy + 12) <= '9') {
-               p = strchr(copy + 12, '.');
-               if (!p) {
-                       free(copy);
-                       return false;
-               }
-               /* strlen("hwaddr") = 6 */
-               if (strlen(p + 1) >= 6)
-                       memmove(copy + 12, p + 1, 6);
-               copy[12 + 6] = '\0';
-       }
-       if (strncmp(copy, "lxc.network.hwaddr", 18) == 0) {
-               free(copy);
+       if (strncmp(line, "lxc.network.hwaddr", 18) == 0)
                return true;
-       }
+       if (sscanf(line, "lxc.net.%u.%6s", &index, tmp) == 2 || sscanf(line, "lxc.network.%u.%6s", &index, tmp) == 2)
+               return strncmp(tmp, "hwaddr", 6) == 0;
 
-       free(copy);
        return false;
 }
 

diff --git a/src/tests/lxc-test-utils.c b/src/tests/lxc-test-utils.c
index 4c3c17a783419b1d3b01ba00704002d2ee44c21d..ddc3dffbe9de4a254789c00d4202ed86fc15a98d 100644 (file)
--- a/src/tests/lxc-test-utils.c
+++ b/src/tests/lxc-test-utils.c
@@ -462,6 +462,29 @@ void test_parse_byte_size_string(void)
                exit(EXIT_FAILURE);
 }
 
+void test_lxc_config_net_hwaddr(void)
+{
+       bool lxc_config_net_hwaddr(const char *line);
+
+       if (!lxc_config_net_hwaddr("lxc.net.0.hwaddr = 00:16:3e:04:65:b8\n"))
+               exit(EXIT_FAILURE);
+       if (!lxc_config_net_hwaddr("lxc.network.hwaddr = 00:16:3e:04:65:b8\n"))
+               exit(EXIT_FAILURE);
+       if (!lxc_config_net_hwaddr("lxc.net.hwaddr = 00:16:3e:04:65:b8\n"))
+               exit(EXIT_FAILURE);
+
+       if (lxc_config_net_hwaddr("lxc.net"))
+               exit(EXIT_FAILURE);
+       if (lxc_config_net_hwaddr("lxc.net."))
+               exit(EXIT_FAILURE);
+       if (lxc_config_net_hwaddr("lxc.net.0."))
+               exit(EXIT_FAILURE);
+       if (lxc_config_net_hwaddr("lxc.network"))
+              exit(EXIT_FAILURE);
+       if (lxc_config_net_hwaddr("lxc.network.0."))
+              exit(EXIT_FAILURE);
+}
+
 int main(int argc, char *argv[])
 {
        test_lxc_string_replace();
@@ -472,6 +495,7 @@ int main(int argc, char *argv[])
        test_lxc_safe_int();
        test_lxc_safe_long();
        test_parse_byte_size_string();
+       test_lxc_config_net_hwaddr();
 
        exit(EXIT_SUCCESS);
 }