[PATCH] D47007: [Sanitizer] CStringChecker fix for strlcpy when no bytes are copied to the dest buffer

[David CARLIER via Phabricator via cfe-commits]

devnexen created this revision.
devnexen added reviewers: NoQ, george.karpenkov.
devnexen created this object with visibility "All Users".
Herald added a subscriber: cfe-commits.

Again strlc* does not return a pointer so the zero size case does not fit.


Repository:
  rC Clang

https://reviews.llvm.org/D47007

Files:
  lib/StaticAnalyzer/Checkers/CStringChecker.cpp
  test/Analysis/bsd-string.c


Index: test/Analysis/bsd-string.c
===================================================================
--- test/Analysis/bsd-string.c
+++ test/Analysis/bsd-string.c
@@ -38,3 +38,8 @@
   size_t len = strlcat(buf, "defg", 4);
   clang_analyzer_eval(len == 7); // expected-warning{{TRUE}}
 }
+
+int f7() {
+  char buf[8];
+  return strlcpy(buf, "1234567", 0); // no-crash
+}
Index: lib/StaticAnalyzer/Checkers/CStringChecker.cpp
===================================================================
--- lib/StaticAnalyzer/Checkers/CStringChecker.cpp
+++ lib/StaticAnalyzer/Checkers/CStringChecker.cpp
@@ -1652,7 +1652,11 @@
 
         // If the size is known to be zero, we're done.
         if (StateZeroSize && !StateNonZeroSize) {
-          StateZeroSize = StateZeroSize->BindExpr(CE, LCtx, DstVal);
+          if (returnPtr) {
+            StateZeroSize = StateZeroSize->BindExpr(CE, LCtx, DstVal);
+          } else {
+            StateZeroSize = StateZeroSize->BindExpr(CE, LCtx, *lenValNL);
+          }
           C.addTransition(StateZeroSize);
           return;
         }



Index: test/Analysis/bsd-string.c
===================================================================
--- test/Analysis/bsd-string.c
+++ test/Analysis/bsd-string.c
@@ -38,3 +38,8 @@
   size_t len = strlcat(buf, "defg", 4);
   clang_analyzer_eval(len == 7); // expected-warning{{TRUE}}
 }
+
+int f7() {
+  char buf[8];
+  return strlcpy(buf, "1234567", 0); // no-crash
+}
Index: lib/StaticAnalyzer/Checkers/CStringChecker.cpp
===================================================================
--- lib/StaticAnalyzer/Checkers/CStringChecker.cpp
+++ lib/StaticAnalyzer/Checkers/CStringChecker.cpp
@@ -1652,7 +1652,11 @@
 
         // If the size is known to be zero, we're done.
         if (StateZeroSize && !StateNonZeroSize) {
-          StateZeroSize = StateZeroSize->BindExpr(CE, LCtx, DstVal);
+          if (returnPtr) {
+            StateZeroSize = StateZeroSize->BindExpr(CE, LCtx, DstVal);
+          } else {
+            StateZeroSize = StateZeroSize->BindExpr(CE, LCtx, *lenValNL);
+          }
           C.addTransition(StateZeroSize);
           return;
         }

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