Sanitize dump payload: handle remaining empty key when RDB loading and restore command (#9349)

This commit mainly fixes empty keys due to RDB loading and restore command,
which was omitted in #9297.

1) When loading quicklsit, if all the ziplists in the quicklist are empty, NULL will be returned.
    If only some of the ziplists are empty, then we will skip the empty ziplists silently.
2) When loading hash zipmap, if zipmap is empty, sanitization check will fail.
3) When loading hash ziplist, if ziplist is empty, NULL will be returned.
4) Add RDB loading test with sanitize.

5 files changed, 63 insertions, 16 deletions

diff --git a/src/rdb.c b/src/rdb.c
index b9ce53c57..111398b4f 100644
--- a/src/rdb.c
+++ b/src/rdb.c
@@ -1827,7 +1827,19 @@ robj *rdbLoadObject(int rdbtype, rio *rdb, sds key, int dbid, int *error) {
                 zfree(zl);
                 return NULL;
             }
-            quicklistAppendZiplist(o->ptr, zl);
+
+            /* Silently skip empty ziplists, if we'll end up with empty quicklist we'll fail later. */
+            if (ziplistLen(zl) == 0) {
+                zfree(zl);
+                continue;
+            } else {
+                quicklistAppendZiplist(o->ptr, zl);
+            }
+        }
+
+        if (quicklistCount(o->ptr) == 0) {
+            decrRefCount(o);
+            goto emptykey;
         }
     } else if (rdbtype == RDB_TYPE_HASH_ZIPMAP  ||
                rdbtype == RDB_TYPE_LIST_ZIPLIST ||
@@ -1910,6 +1922,14 @@ robj *rdbLoadObject(int rdbtype, rio *rdb, sds key, int dbid, int *error) {
                     decrRefCount(o);
                     return NULL;
                 }
+
+                if (ziplistLen(encoded) == 0) {
+                    zfree(encoded);
+                    o->ptr = NULL;
+                    decrRefCount(o);
+                    goto emptykey;
+                }
+
                 o->type = OBJ_LIST;
                 o->encoding = OBJ_ENCODING_ZIPLIST;
                 listTypeConvert(o,OBJ_ENCODING_QUICKLIST);
diff --git a/src/ziplist.c b/src/ziplist.c
index 1b934a292..b55c85fcf 100644
--- a/src/ziplist.c
+++ b/src/ziplist.c
@@ -1527,7 +1527,7 @@ int ziplistValidateIntegrity(unsigned char *zl, size_t size, int deep,
         return 0;
 
     /* Make sure the <zltail> entry really do point to the start of the last entry. */
-    if (prev != ZIPLIST_ENTRY_TAIL(zl))
+    if (prev != NULL && prev != ZIPLIST_ENTRY_TAIL(zl))
         return 0;
 
     /* Check that the count in the header is correct */
diff --git a/src/zipmap.c b/src/zipmap.c
index e39c27708..22cf17cbb 100644
--- a/src/zipmap.c
+++ b/src/zipmap.c
@@ -430,6 +430,9 @@ int zipmapValidateIntegrity(unsigned char *zm, size_t size, int deep) {
             return 0;
     }
 
+    /* check that the zipmap is not empty. */
+    if (count == 0) return 0;
+
     /* check that the count in the header is correct */
     if (zm[0] != ZIPMAP_BIGLEN && zm[0] != count)
         return 0;
diff --git a/tests/assets/corrupt_empty_keys.rdb b/tests/assets/corrupt_empty_keys.rdb
index bc2b4f202..8f260d493 100644
--- a/tests/assets/corrupt_empty_keys.rdb
+++ b/tests/assets/corrupt_empty_keys.rdb
diff --git a/tests/integration/corrupt-dump.tcl b/tests/integration/corrupt-dump.tcl
index 554de609e..468082b91 100644
--- a/tests/integration/corrupt-dump.tcl
+++ b/tests/integration/corrupt-dump.tcl
@@ -118,6 +118,16 @@ test {corrupt payload: #3080 - quicklist} {
     }
 }
 
+test {corrupt payload: quicklist with empty ziplist} {
+    start_server [list overrides [list loglevel verbose use-exit-on-panic yes crash-memcheck-enabled no] ] {
+        r config set sanitize-dump-payload no
+        r debug set-skip-checksum-validation 1
+        catch {r restore key 0 "\x0E\x01\x0B\x0B\x00\x00\x00\x0A\x00\x00\x00\x00\x00\xFF\x09\x00\xC2\x69\x37\x83\x3C\x7F\xFE\x6F" replace} err
+        assert_match "*Bad data format*" $err
+        r ping
+    }
+}
+
 test {corrupt payload: #3080 - ziplist} {
     start_server [list overrides [list loglevel verbose use-exit-on-panic yes crash-memcheck-enabled no] ] {
         # shallow sanitization is enough for restore to safely reject the payload with wrong size
@@ -148,20 +158,24 @@ test {corrupt payload: load corrupted rdb with no CRC - #3505} {
     kill_server $srv ;# let valgrind look for issues
 }
 
-test {corrupt payload: load corrupted rdb with empty keys} {
-    set server_path [tmpdir "server.rdb-corruption-empty-keys-test"]
-    exec cp tests/assets/corrupt_empty_keys.rdb $server_path
-    start_server [list overrides [list "dir" $server_path "dbfilename" "corrupt_empty_keys.rdb"]] {
-        r select 0
-        assert_equal [r dbsize] 0
-
-        verify_log_message 0 "*skipping empty key: set*" 0
-        verify_log_message 0 "*skipping empty key: quicklist*" 0
-        verify_log_message 0 "*skipping empty key: hash*" 0
-        verify_log_message 0 "*skipping empty key: hash_ziplist*" 0
-        verify_log_message 0 "*skipping empty key: zset*" 0
-        verify_log_message 0 "*skipping empty key: zset_ziplist*" 0
-        verify_log_message 0 "*empty keys skipped: 6*" 0
+foreach sanitize_dump {no yes} {
+    test {corrupt payload: load corrupted rdb with empty keys} {
+        set server_path [tmpdir "server.rdb-corruption-empty-keys-test"]
+        exec cp tests/assets/corrupt_empty_keys.rdb $server_path
+        start_server [list overrides [list "dir" $server_path "dbfilename" "corrupt_empty_keys.rdb" "sanitize-dump-payload" $sanitize_dump]] {
+            r select 0
+            assert_equal [r dbsize] 0
+
+            verify_log_message 0 "*skipping empty key: set*" 0
+            verify_log_message 0 "*skipping empty key: list_quicklist*" 0
+            verify_log_message 0 "*skipping empty key: list_quicklist_empty_ziplist*" 0
+            verify_log_message 0 "*skipping empty key: list_ziplist*" 0
+            verify_log_message 0 "*skipping empty key: hash*" 0
+            verify_log_message 0 "*skipping empty key: hash_ziplist*" 0
+            verify_log_message 0 "*skipping empty key: zset*" 0
+            verify_log_message 0 "*skipping empty key: zset_ziplist*" 0
+            verify_log_message 0 "*empty keys skipped: 8*" 0
+        }
     }
 }
 
@@ -241,6 +255,16 @@ test {corrupt payload: hash duplicate records} {
     }
 }
 
+test {corrupt payload: hash empty zipmap} {
+    start_server [list overrides [list loglevel verbose use-exit-on-panic yes crash-memcheck-enabled no] ] {
+        r config set sanitize-dump-payload no
+        r debug set-skip-checksum-validation 1
+        catch { r RESTORE _hash 0 "\x09\x02\x00\xFF\x09\x00\xC0\xF1\xB8\x67\x4C\x16\xAC\xE3" } err
+        assert_match "*Bad data format*" $err
+        verify_log_message 0 "*Zipmap integrity check failed*" 0
+    }
+}
+
 test {corrupt payload: fuzzer findings - NPD in streamIteratorGetID} {
     start_server [list overrides [list loglevel verbose use-exit-on-panic yes crash-memcheck-enabled no] ] {
         r config set sanitize-dump-payload no