[clang] [clang][analyzer] Support `fprintf` in the SecuritySyntaxChecker (PR #73247)

[via cfe-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-clang

Author: Ben Shi (benshi001)

<details>
<summary>Changes</summary>



---
Full diff: https://github.com/llvm/llvm-project/pull/73247.diff


2 Files Affected:

- (modified) clang/lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp (+7-6) 
- (modified) clang/test/Analysis/security-syntax-checks.c (+12-3) 


``````````diff
diff --git a/clang/lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp b/clang/lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp
index 1a88615f01697cb..e96f8f131e0034b 100644
--- a/clang/lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/CheckSecuritySyntaxOnly.cpp
@@ -162,7 +162,7 @@ void WalkAST::VisitCallExpr(CallExpr *CE) {
     .Cases("sscanf", "swscanf", "vsscanf", "vswscanf", "swprintf",
            "snprintf", "vswprintf", "vsnprintf", "memcpy", "memmove",
            &WalkAST::checkDeprecatedOrUnsafeBufferHandling)
-    .Cases("strncpy", "strncat", "memset",
+    .Cases("strncpy", "strncat", "memset", "fprintf",
            &WalkAST::checkDeprecatedOrUnsafeBufferHandling)
     .Case("drand48", &WalkAST::checkCall_rand)
     .Case("erand48", &WalkAST::checkCall_rand)
@@ -737,10 +737,10 @@ void WalkAST::checkCall_strcat(const CallExpr *CE, const FunctionDecl *FD) {
 // Check: Any use of 'sprintf', 'vsprintf', 'scanf', 'wscanf', 'fscanf',
 //        'fwscanf', 'vscanf', 'vwscanf', 'vfscanf', 'vfwscanf', 'sscanf',
 //        'swscanf', 'vsscanf', 'vswscanf', 'swprintf', 'snprintf', 'vswprintf',
-//        'vsnprintf', 'memcpy', 'memmove', 'strncpy', 'strncat', 'memset'
-//        is deprecated since C11.
+//        'vsnprintf', 'memcpy', 'memmove', 'strncpy', 'strncat', 'memset',
+//        'fprintf' is deprecated since C11.
 //
-//        Use of 'sprintf', 'vsprintf', 'scanf', 'wscanf','fscanf',
+//        Use of 'sprintf', 'fprintf', 'vsprintf', 'scanf', 'wscanf', 'fscanf',
 //        'fwscanf', 'vscanf', 'vwscanf', 'vfscanf', 'vfwscanf', 'sscanf',
 //        'swscanf', 'vsscanf', 'vswscanf' without buffer limitations
 //        is insecure.
@@ -768,8 +768,9 @@ void WalkAST::checkDeprecatedOrUnsafeBufferHandling(const CallExpr *CE,
   int ArgIndex =
       llvm::StringSwitch<int>(Name)
           .Cases("scanf", "wscanf", "vscanf", "vwscanf", 0)
-          .Cases("sprintf", "vsprintf", "fscanf", "fwscanf", "vfscanf",
-                 "vfwscanf", "sscanf", "swscanf", "vsscanf", "vswscanf", 1)
+          .Cases("fscanf", "fwscanf", "vfscanf", "vfwscanf", "sscanf",
+                 "swscanf", "vsscanf", "vswscanf", 1)
+          .Cases("sprintf", "vsprintf", "fprintf", 1)
           .Cases("swprintf", "snprintf", "vswprintf", "vsnprintf", "memcpy",
                  "memmove", "memset", "strncpy", "strncat", DEPR_ONLY)
           .Default(UNKNOWN_CALL);
diff --git a/clang/test/Analysis/security-syntax-checks.c b/clang/test/Analysis/security-syntax-checks.c
index 392a65ff5f167ce..2c904f41623fcd1 100644
--- a/clang/test/Analysis/security-syntax-checks.c
+++ b/clang/test/Analysis/security-syntax-checks.c
@@ -5,15 +5,24 @@
 // RUN: %clang_analyze_cc1 %s -verify -std=gnu99 \
 // RUN:   -analyzer-checker=security.insecureAPI
 
+#include "Inputs/system-header-simulator.h"
+
+extern FILE *fp;
+extern char buf[128];
+
 void builtin_function_call_crash_fixes(char *c) {
   __builtin_strncpy(c, "", 6);
   __builtin_memset(c, '\0', (0));
   __builtin_memcpy(c, c, 0);
+  __builtin_sprintf(buf, "%s", c);
+  __builtin_fprintf(fp, "%s", c);
 
 #if __STDC_VERSION__ > 199901
-  // expected-warning at -5{{Call to function 'strncpy' is insecure as it does not provide security checks introduced in the C11 standard.}}
-  // expected-warning at -5{{Call to function 'memset' is insecure as it does not provide security checks introduced in the C11 standard.}}
-  // expected-warning at -5{{Call to function 'memcpy' is insecure as it does not provide security checks introduced in the C11 standard.}}
+  // expected-warning at -7{{Call to function 'strncpy' is insecure as it does not provide security checks introduced in the C11 standard.}}
+  // expected-warning at -7{{Call to function 'memset' is insecure as it does not provide security checks introduced in the C11 standard.}}
+  // expected-warning at -7{{Call to function 'memcpy' is insecure as it does not provide security checks introduced in the C11 standard.}}
+  // expected-warning at -7{{Call to function 'sprintf' is insecure as it does not provide bounding of the memory buffer or security checks introduced in the C11 standard.}}
+  // expected-warning at -7{{Call to function 'fprintf' is insecure as it does not provide bounding of the memory buffer or security checks introduced in the C11 standard.}}
 #else
   // expected-no-diagnostics
 #endif

``````````

</details>


https://github.com/llvm/llvm-project/pull/73247