confile: use deindexed network keys

When we are passed a network key like "lxc.net.[i].ipv4.address" we need to
make sure that we pass the deindexed key "lxc.net.ipv4.address" to the
{get,clr,set} methods otherwise we'll end up in an endless loop.

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/confile.c b/src/lxc/confile.c
index 55917e8c45514762b931b27e4bab0192d6417d6c..8583419524a507fbea2b514d22d11b03ebb12e88 100644 (file)
--- a/src/lxc/confile.c
+++ b/src/lxc/confile.c
@@ -3680,72 +3680,88 @@ static int get_config_includefiles(const char *key, char *retv, int inlen,
        return -ENOSYS;
 }
 
-static struct lxc_config_t *
-get_network_config_ops(const char *key, struct lxc_conf *lxc_conf, ssize_t *idx)
+static struct lxc_config_t *get_network_config_ops(const char *key,
+                                                  struct lxc_conf *lxc_conf,
+                                                  ssize_t *idx,
+                                                  char **deindexed_key)
 {
+       int ret;
+       unsigned int tmpidx;
+       size_t numstrlen;
        char *copy, *idx_start, *idx_end;
        struct lxc_config_t *config = NULL;
 
        /* check that this is a sensible network key */
-       if (strncmp("lxc.net.", key, 8))
+       if (strncmp("lxc.net.", key, 8)) {
+               ERROR("Invalid network configuration key \"%s\"", key);
                return NULL;
+       }
 
        copy = strdup(key);
-       if (!copy)
+       if (!copy) {
+               ERROR("Failed to duplicate string \"%s\"", key);
                return NULL;
+       }
 
        /* lxc.net.<n> */
-       if (isdigit(*(key + 8))) {
-               int ret;
-               unsigned int tmpidx;
-               size_t numstrlen;
-
-               /* beginning of index string */
-               idx_start = (copy + 7);
-               *idx_start = '\0';
-
-               /* end of index string */
-               idx_end = strchr((copy + 8), '.');
-               if (!idx_end)
-                       goto on_error;
-               *idx_end = '\0';
-
-               /* parse current index */
-               ret = lxc_safe_uint((idx_start + 1), &tmpidx);
-               if (ret < 0) {
-                       *idx = ret;
-                       goto on_error;
-               }
-
-               /* This, of course is utterly nonsensical on so many levels, but
-                * better safe than sorry.
-                * (Checking for INT_MAX here is intentional.)
-                */
-               if (tmpidx == INT_MAX) {
-                       SYSERROR(
-                           "number of configured networks would overflow the "
-                           "counter... what are you doing?");
-                       goto on_error;
-               }
-               *idx = tmpidx;
+       if (!isdigit(*(key + 8))) {
+               ERROR("Failed to detect digit in string \"%s\"", key + 8);
+               goto on_error;
+       }
 
-               numstrlen = strlen((idx_start + 1));
+       /* beginning of index string */
+       idx_start = (copy + 7);
+       *idx_start = '\0';
 
-               /* repair configuration key */
-               *idx_start = '.';
-               *idx_end = '.';
+       /* end of index string */
+       idx_end = strchr((copy + 8), '.');
+       if (!idx_end) {
+               ERROR("Failed to detect \".\" in string \"%s\"", (copy + 8));
+               goto on_error;
+       }
+       *idx_end = '\0';
+
+       /* parse current index */
+       ret = lxc_safe_uint((idx_start + 1), &tmpidx);
+       if (ret < 0) {
+               ERROR("Failed to parse usigned integer from string \"%s\": %s",
+                     idx_start + 1, strerror(-ret));
+               *idx = ret;
+               goto on_error;
+       }
 
-               memmove(copy + 8, idx_end + 1, strlen(idx_end + 1));
-               copy[strlen(key) - numstrlen + 1] = '\0';
+       /* This, of course is utterly nonsensical on so many levels, but
+        * better safe than sorry.
+        * (Checking for INT_MAX here is intentional.)
+        */
+       if (tmpidx == INT_MAX) {
+               SYSERROR("number of configured networks would overflow the "
+                        "counter... what are you doing?");
+               goto on_error;
        }
+       *idx = tmpidx;
+
+       numstrlen = strlen((idx_start + 1));
+
+       /* repair configuration key */
+       *idx_start = '.';
+       *idx_end = '.';
+
+       memmove(copy + 8, idx_end + 1, strlen(idx_end + 1));
+       copy[strlen(key) - numstrlen + 1] = '\0';
 
        config = lxc_getconfig(copy);
-       if (!config)
+       if (!config) {
                ERROR("unknown network configuration key %s", key);
+               goto on_error;
+       }
+
+       *deindexed_key = copy;
+       return config;
 
 on_error:
        free(copy);
-       return config;
+       return NULL;
 }
 
 /*
@@ -3756,22 +3772,33 @@ on_error:
 static int set_config_net_nic(const char *key, const char *value,
                              struct lxc_conf *lxc_conf, void *data)
 {
+       int ret;
+       const char *idxstring;
        struct lxc_config_t *config;
        struct lxc_netdev *netdev;
        ssize_t idx = -1;
+       char *deindexed_key = NULL;
+
+       idxstring = key + 8;
+       if (!isdigit(*idxstring))
+               return -1;
 
        if (lxc_config_value_empty(value))
                return clr_config_net_nic(key, lxc_conf, data);
 
-       config = get_network_config_ops(key, lxc_conf, &idx);
+       config = get_network_config_ops(key, lxc_conf, &idx, &deindexed_key);
        if (!config || idx < 0)
                return -1;
 
        netdev = lxc_get_netdev_by_idx(lxc_conf, (unsigned int)idx, true);
-       if (!netdev)
+       if (!netdev) {
+               free(deindexed_key);
                return -1;
+       }
 
-       return config->set(key, value, lxc_conf, netdev);
+       ret = config->set(deindexed_key, value, lxc_conf, netdev);
+       free(deindexed_key);
+       return ret;
 }
 
 /*
@@ -3782,18 +3809,19 @@ static int set_config_net_nic(const char *key, const char *value,
 static int clr_config_net_nic(const char *key, struct lxc_conf *lxc_conf,
                              void *data)
 {
+       int ret;
        const char *idxstring;
        struct lxc_config_t *config;
        struct lxc_netdev *netdev;
-       ssize_t idx;
+       ssize_t idx = -1;
+       char *deindexed_key = NULL;
 
-       /* If we get passed "lxc.net.<n>" we clear the whole network. */
-       if (strncmp("lxc.net.", key, 8))
+       idxstring = key + 8;
+       if (!isdigit(*idxstring))
                return -1;
 
-       idxstring = key + 8;
        /* The left conjunct is pretty self-explanatory. The right conjunct
-        * checks whether the two pointers are equal. If they are we now that
+        * checks whether the two pointers are equal. If they are we know that
         * this is not a key that is namespaced any further and so we are
         * supposed to clear the whole network.
         */
@@ -3808,15 +3836,19 @@ static int clr_config_net_nic(const char *key, struct lxc_conf *lxc_conf,
                return 0;
        }
 
-       config = get_network_config_ops(key, lxc_conf, &idx);
+       config = get_network_config_ops(key, lxc_conf, &idx, &deindexed_key);
        if (!config || idx < 0)
                return -1;
 
        netdev = lxc_get_netdev_by_idx(lxc_conf, (unsigned int)idx, false);
-       if (!netdev)
+       if (!netdev) {
+               free(deindexed_key);
                return -1;
+       }
 
-       return config->clr(key, lxc_conf, netdev);
+       ret = config->clr(deindexed_key, lxc_conf, netdev);
+       free(deindexed_key);
+       return ret;
 }
 
 static int clr_config_net_type(const char *key, struct lxc_conf *lxc_conf,
@@ -4099,19 +4131,30 @@ static int clr_config_net_ipv6_address(const char *key,
 static int get_config_net_nic(const char *key, char *retv, int inlen,
                              struct lxc_conf *c, void *data)
 {
+       int ret;
+       const char *idxstring;
        struct lxc_config_t *config;
        struct lxc_netdev *netdev;
        ssize_t idx = -1;
+       char *deindexed_key = NULL;
 
-       config = get_network_config_ops(key, c, &idx);
+       idxstring = key + 8;
+       if (!isdigit(*idxstring))
+               return -1;
+
+       config = get_network_config_ops(key, c, &idx, &deindexed_key);
        if (!config || idx < 0)
                return -1;
 
        netdev = lxc_get_netdev_by_idx(c, (unsigned int)idx, false);
-       if (!netdev)
+       if (!netdev) {
+               free(deindexed_key);
                return -1;
+       }
 
-       return config->get(key, retv, inlen, c, netdev);
+       ret = config->get(deindexed_key, retv, inlen, c, netdev);
+       free(deindexed_key);
+       return ret;
 }
 
 static int get_config_net_type(const char *key, char *retv, int inlen,