From 29af6f45170cdcc1800c22c89de0caa7663fe399 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Wed, 19 Mar 2025 14:10:14 +0000
Subject: [PATCH] Create rule S7438 Incompatible bit masks should not be used
 in comparisons (#4781)

* Create rule S7438

* Update rule.adoc

* Update metadata.json

* Update metadata.json

* Update metadata.json

* Update rule.adoc

* Update metadata.json

* Update rule.adoc

---------

Co-authored-by: sallaigy <sallaigy@users.noreply.github.com>
Co-authored-by: Gyula Sallai <gyula.sallai@sonarsource.com>
---
 rules/S7438/metadata.json      |  2 ++
 rules/S7438/rust/metadata.json | 24 +++++++++++++++++++
 rules/S7438/rust/rule.adoc     | 42 ++++++++++++++++++++++++++++++++++
 3 files changed, 68 insertions(+)
 create mode 100644 rules/S7438/metadata.json
 create mode 100644 rules/S7438/rust/metadata.json
 create mode 100644 rules/S7438/rust/rule.adoc

diff --git a/rules/S7438/metadata.json b/rules/S7438/metadata.json
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index 0000000000..2c63c08510
--- /dev/null
+++ b/rules/S7438/metadata.json
@@ -0,0 +1,2 @@
+{
+}
diff --git a/rules/S7438/rust/metadata.json b/rules/S7438/rust/metadata.json
new file mode 100644
index 0000000000..8c8ff71754
--- /dev/null
+++ b/rules/S7438/rust/metadata.json
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+{
+  "title": "Incompatible bit masks should not be used in comparisons",
+  "type": "BUG",
+  "status": "ready",
+  "remediation": {
+    "func": "Constant\/Issue",
+    "constantCost": "5min"
+  },
+  "tags": [
+    "clippy"
+  ],
+  "defaultSeverity": "Blocker",
+  "ruleSpecification": "RSPEC-7438",
+  "sqKey": "S7438",
+  "scope": "All",
+  "defaultQualityProfiles": ["Sonar way"],
+  "quickfix": "unknown",
+  "code": {
+    "impacts": {
+      "RELIABILITY": "HIGH"
+    },
+    "attribute": "LOGICAL"
+  }
+}
diff --git a/rules/S7438/rust/rule.adoc b/rules/S7438/rust/rule.adoc
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index 0000000000..eb3620b129
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+
+== Why is this an issue?
+If the bits that the comparison cares about are always set to zero or one by the bit mask, the comparison is constant true or false (depending on mask, compared value, and operators). This results in dead code, potential security vulnerabilities, confusion for developers, and wasted processing time on redundant checks.
+
+== How to fix it
+
+Ensuring valid bitwise operations in comparisons requires:
+
+* For `&` (AND) operations:
+  ** `x & mask == value` is valid if all bits set in `value` are also set in `mask`
+  ** `x & mask < value` is valid if `mask < value`
+  ** `x & mask > value` is valid if `mask > value`
+* For `|` (OR) operations:
+  ** `x | mask == value` is valid if all bits set in `mask` are also set in `value`
+  
+Correct the bit mask or comparison value to create a valid logical expression that can be both true and false depending on input. This ensures the bitwise operations in the comparisons result in meaningful code execution.
+
+=== Code examples
+
+==== Noncompliant code example
+[source,rust,diff-id=1,diff-type=noncompliant]
+----
+let x = 1;
+if (x & 1 == 2) { 
+    // This code will never execute
+}
+----
+
+==== Compliant solution
+
+[source,rust,diff-id=1,diff-type=compliant]
+----
+let x = 1;
+if (x & 2 == 2) { 
+    // This code will execute when the second bit of x is set
+}
+----
+
+== Resources
+=== Documentation
+
+* Clippy Lints - https://rust-lang.github.io/rust-clippy/master/index.html#bad_bit_mask