Revert using strncmp instead of strcmp to make the function robust an…

…d safe from buffer overruns. #33449 (#33482) * Add tests for Nullable String attribute * Use strcmp instead of strncmp to compare a null-terminated arg
project-chip · May 16, 2024 · 22b9c96 · 22b9c96
1 parent fef9ee3
commit 22b9c96
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Showing 3 changed files with 15 additions and 3 deletions.
diff --git a/examples/chip-tool/commands/common/Command.cpp b/examples/chip-tool/commands/common/Command.cpp
@@ -171,7 +171,7 @@ bool HandleNullableOptional(Argument & arg, char * argValue, std::function<bool(
     if (arg.isNullable())
     {
         auto * nullable = reinterpret_cast<chip::app::DataModel::Nullable<T> *>(arg.value);
-        if (argValue != nullptr && strncmp(argValue, "null", 4) == 0)
+        if (strcmp(argValue, "null") == 0)
         {
             nullable->SetNull();
             return true;

diff --git a/examples/fabric-admin/commands/common/Command.cpp b/examples/fabric-admin/commands/common/Command.cpp
@@ -171,7 +171,7 @@ bool HandleNullableOptional(Argument & arg, char * argValue, std::function<bool(
     if (arg.isNullable())
     {
         auto * nullable = reinterpret_cast<chip::app::DataModel::Nullable<T> *>(arg.value);
-        if (argValue != nullptr && strncmp(argValue, "null", 4) == 0)
+        if (strcmp(argValue, "null") == 0)
         {
             nullable->SetNull();
             return true;

diff --git a/src/app/tests/suites/TestCluster.yaml b/src/app/tests/suites/TestCluster.yaml
@@ -2896,7 +2896,7 @@ tests:
           constraints:
               notValue: nullableOctetStrTestValue
 
-    # Tests for Char String attribute
+    # Tests for Nullable Char String attribute
 
     - label: "Read attribute NULLABLE_CHAR_STRING Default Value"
       command: "readAttribute"
@@ -2968,6 +2968,18 @@ tests:
       response:
           error: UNSUPPORTED_CLUSTER
 
+    - label: "Write attribute NULLABLE_CHAR_STRING - Value starting with null"
+      command: "writeAttribute"
+      attribute: "nullable_char_string"
+      arguments:
+          value: "nulla"
+
+    - label: "Read attribute NULLABLE_CHAR_STRING"
+      command: "readAttribute"
+      attribute: "nullable_char_string"
+      response:
+          value: "nulla"
+
     # Tests for command with optional arguments
     - label:
           "Send a command that takes an optional parameter but do not set it."