(doris) branch master updated: [fix](function) Return null for invalid base64 input length (#64788)

[yanxuecheng]

This is an automated email from the ASF dual-hosted git repository.

Mryange pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/doris.git


The following commit(s) were added to refs/heads/master by this push:
     new 86ac986053c [fix](function) Return null for invalid base64 input 
length (#64788)
86ac986053c is described below

commit 86ac986053c20b5378fc5d7235035c2903b5e442
Author: Mryange <yanxuech...@selectdb.com>
AuthorDate: Thu Jun 25 10:22:26 2026 +0800

    [fix](function) Return null for invalid base64 input length (#64788)
    
    ### What problem does this PR solve?
    
    
    
    `from_base64` and `from_base64_binary` call the base64 decoder after
    sizing the output buffer from `len / 4 * 3`. For invalid input whose
    length is not a multiple of four, this can pass an undersized
    destination buffer into the decoder before the function marks the row as
    invalid.
    
    Root cause: the functions only handled decoder failure after invoking
    the decoder, but did not reject impossible base64 lengths first.
    
    This patch returns `NULL` for inputs with invalid base64 length before
    decoding, keeping the existing invalid-input SQL behavior while avoiding
    unsafe decoder calls.
    
    
    ### Release note
    
    None
---
 be/src/exprs/function/function_string.cpp          | 6 ++++++
 be/src/exprs/function/function_varbinary.cpp       | 5 +++++
 be/test/exprs/function/function_string_test.cpp    | 3 +++
 be/test/exprs/function/function_varbinary_test.cpp | 3 +++
 4 files changed, 17 insertions(+)

diff --git a/be/src/exprs/function/function_string.cpp 
b/be/src/exprs/function/function_string.cpp
index 86c3e0f6a69..c1b2c3bad51 100644
--- a/be/src/exprs/function/function_string.cpp
+++ b/be/src/exprs/function/function_string.cpp
@@ -1185,6 +1185,12 @@ struct FromBase64Impl {
                 continue;
             }
 
+            if (UNLIKELY(srclen % 4 != 0)) {
+                null_map[i] = 1;
+                dst_offsets[i] = cast_set<uint32_t>(offset);
+                continue;
+            }
+
             auto outlen = base64_decode(source, srclen, dst_data_ptr + offset);
 
             if (outlen < 0) {
diff --git a/be/src/exprs/function/function_varbinary.cpp 
b/be/src/exprs/function/function_varbinary.cpp
index 5c02e637a5c..4cc406fa258 100644
--- a/be/src/exprs/function/function_varbinary.cpp
+++ b/be/src/exprs/function/function_varbinary.cpp
@@ -230,6 +230,11 @@ struct FromBase64BinaryImpl {
                 continue;
             }
 
+            if (UNLIKELY(slen % 4 != 0)) {
+                null_map[i] = 1;
+                continue;
+            }
+
             int cipher_len = slen / 4 * 3;
             auto [cipher_inline, dst] = VarBinaryOP::alloc(res, i, cipher_len);
 
diff --git a/be/test/exprs/function/function_string_test.cpp 
b/be/test/exprs/function/function_string_test.cpp
index 2e1aaa839c4..9b7e0d793ab 100644
--- a/be/test/exprs/function/function_string_test.cpp
+++ b/be/test/exprs/function/function_string_test.cpp
@@ -1599,6 +1599,9 @@ TEST(function_string_test, function_from_base64_test) {
             {{std::string("5ZWK5ZOI5ZOI5ZOI8J+YhCDjgILigJTigJQh")},
              std::string("啊哈哈哈😄 。——!")},
             {{std::string("ò&ø")}, Null()},
+            {{std::string("bad@")}, Null()},
+            {{std::string("====")}, Null()},
+            {{std::string("YQ")}, Null()},
             {{std::string("TVl0ZXN0U1RS")}, std::string("MYtestSTR")},
             {{Null()}, Null()},
     };
diff --git a/be/test/exprs/function/function_varbinary_test.cpp 
b/be/test/exprs/function/function_varbinary_test.cpp
index bfd87ae1143..c0fe3b02f1c 100644
--- a/be/test/exprs/function/function_varbinary_test.cpp
+++ b/be/test/exprs/function/function_varbinary_test.cpp
@@ -100,6 +100,9 @@ TEST(function_binary_test, 
function_from_base64_binary_test) {
             {{std::string("")}, VARBINARY("")},
             {{std::string("5ZWK5ZOI5ZOI5ZOI8J+YhCDjgILigJTigJQh")}, 
VARBINARY("啊哈哈哈😄 。——!")},
             {{std::string("ò&ø")}, Null()},
+            {{std::string("bad@")}, Null()},
+            {{std::string("====")}, Null()},
+            {{std::string("YQ")}, Null()},
             {{std::string("TVl0ZXN0U1RS")}, VARBINARY("MYtestSTR")},
             {{std::string("YWFhYWFhYWFhYWE=")}, VARBINARY("aaaaaaaaaaa")},
             {{std::string("TVl0ZXN0U1RSTVl0ZXN0U1RSTVl0ZXN0U1RS")},


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