[PATCH 04/14] vshCmddefCheckInternals: Sanitize command alias validation

[Peter Krempa <pkrempa@xxxxxxxxxx>]

We don't need to validate the real command twice, but it's better to
check that the real command name exists and it's not an alias to prevent
loops.

Signed-off-by: Peter Krempa <pkrempa@xxxxxxxxxx>
---
 tools/vsh.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/tools/vsh.c b/tools/vsh.c
index eb17a58dc0..05da50eace 100644
--- a/tools/vsh.c
+++ b/tools/vsh.c
@@ -269,11 +269,27 @@ vshCmddefCheckInternals(vshControl *ctl,

     /* in order to perform the validation resolve the alias first */
     if (cmd->flags & VSH_CMD_FLAG_ALIAS) {
+        const vshCmdDef *alias;
+
         if (!cmd->alias) {
             vshError(ctl, _("command '%s' has inconsistent alias"), cmd->name);
             return -1;
         }
-        cmd = vshCmddefSearch(cmd->alias);
+
+        if (!(alias = vshCmddefSearch(cmd->alias))) {
+            vshError(ctl, _("command alias '%s' is pointing to a non-existant command '%s'"),
+                     cmd->name, cmd->alias);
+            return -1;
+        }
+
+        if (alias->flags & VSH_CMD_FLAG_ALIAS) {
+            vshError(ctl, _("command alias '%s' is pointing to another command alias '%s'"),
+                     cmd->name, cmd->alias);
+            return -1;
+        }
+
+        /* we don't need to continue as the real command will be checked separately */
+        return 0;
     }

     /* Each command has to provide a non-empty help string. */
-- 
2.31.1