[lldb] Fix off by one in array index check in Objective C runtime plugin (llvm#118995)

DavidSpickett · adrian-prantl · commit 35c17c1188bc · 2024-12-06T14:35:43.000-08:00
Reported in llvm#116944 / https://pvs-studio.com/en/blog/posts/cpp/1188/. (cherry picked from commit a46ee73)
diff --git a/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp b/lldb/source/Plugins/LanguageRuntime/ObjC/AppleObjCRuntime/AppleObjCRuntimeV2.cpp
@@ -3291,7 +3291,7 @@ bool AppleObjCRuntimeV2::NonPointerISACache::EvaluateNonPointerISA(
       }
 
       // If the index is still out of range then this isn't a pointer.
-      if (index > m_indexed_isa_cache.size())
+      if (index >= m_indexed_isa_cache.size())
         return false;
 
       LLDB_LOGF(log, "AOCRT::NPI Evaluate(ret_isa = 0x%" PRIx64 ")",

Original file line number	Diff line number	Diff line change
`@@ -3291,7 +3291,7 @@ bool AppleObjCRuntimeV2::NonPointerISACache::EvaluateNonPointerISA(`
`3291`	`3291`	`}`
`3292`	`3292`
`3293`	`3293`	`// If the index is still out of range then this isn't a pointer.`
`3294`		`- if (index > m_indexed_isa_cache.size())`
	`3294`	`+ if (index >= m_indexed_isa_cache.size())`
`3295`	`3295`	`return false;`
`3296`	`3296`
`3297`	`3297`	`LLDB_LOGF(log, "AOCRT::NPI Evaluate(ret_isa = 0x%" PRIx64 ")",`