Hide user data from log (#13400)

This PR is based on the commits from PR #11747.

In the event of an assertion failure, hide command arguments from the
operator.

In some cases, private client information can be voluntarily exposed
when a redis instance crashes due to an assertion failure.
This commit prevent וnintentional client info exposure.
Operators can still access the hidden data, but they must actively
request it.
Any of the client info commands remains the unchanged.

### Config
Add a new config `hide-user-data-from-log` to turn this feature on and
off, default off.

---------

Co-authored-by: naglera <anagler123@gmail.com>
Co-authored-by: naglera <58042354+naglera@users.noreply.github.com>

src/debug.c

@@ -4,6 +4,8 @@
  *
  * Licensed under your choice of the Redis Source Available License 2.0
  * (RSALv2) or the Server Side Public License v1 (SSPLv1).
+ *
+ * Portions of this file are available under BSD3 terms; see REDISCONTRIBUTIONS for more information.
  */
 
 #include "server.h"
@@ -1067,6 +1069,11 @@ void _serverAssert(const char *estr, const char *file, int line) {
     bugReportEnd(0, 0);
 }
 
+/* Returns the amount of client's command arguments we allow logging */
+int clientArgsToLog(const client *c) {
+    return server.hide_user_data_from_log ? 1 : c->argc;
+}
+
 void _serverAssertPrintClientInfo(const client *c) {
     int j;
     char conninfo[CONN_INFO_LEN];
@@ -1077,6 +1084,10 @@ void _serverAssertPrintClientInfo(const client *c) {
     serverLog(LL_WARNING,"client->conn = %s", connGetInfo(c->conn, conninfo, sizeof(conninfo)));
     serverLog(LL_WARNING,"client->argc = %d", c->argc);
     for (j=0; j < c->argc; j++) {
+        if (j >= clientArgsToLog(c)) {
+            serverLog(LL_WARNING,"client->argv[%d] = *redacted*",j);
+            continue;
+        }
         char buf[128];
         char *arg;
 
@@ -1275,6 +1286,10 @@ static void* getAndSetMcontextEip(ucontext_t *uc, void *eip) {
 
 REDIS_NO_SANITIZE("address")
 void logStackContent(void **sp) {
+    if (server.hide_user_data_from_log) {
+        serverLog(LL_NOTICE,"hide-user-data-from-log is on, skip logging stack content to avoid spilling PII.");
+        return;
+    }
     int i;
     for (i = 15; i >= 0; i--) {
         unsigned long addr = (unsigned long) sp+i;
@@ -2050,6 +2065,10 @@ void logCurrentClient(client *cc, const char *title) {
     sdsfree(client);
     serverLog(LL_WARNING|LL_RAW,"argc: '%d'\n", cc->argc);
     for (j = 0; j < cc->argc; j++) {
+        if (j >= clientArgsToLog(cc)) {
+            serverLog(LL_WARNING|LL_RAW,"argv[%d]: *redacted*\n",j);
+            continue;
+        }
         robj *decoded;
         decoded = getDecodedObject(cc->argv[j]);
         sds repr = sdscatrepr(sdsempty(),decoded->ptr, min(sdslen(decoded->ptr), 128));