Fix a range check when reading from ELF files

godlygeek · pablogsal · commit 5b758225e1fd · 2025-02-13T01:39:25.000Z
The end address is exclusive, not inclusive. This off-by-one could mean
that we look at the wrong shared library for a given address if it
occurs at the very start of start of a mapping.

Signed-off-by: Pablo Galindo &lt;pablogsal@gmail.com&gt;
diff --git a/src/pystack/_pystack/mem.cpp b/src/pystack/_pystack/mem.cpp
@@ -464,7 +464,7 @@ CorefileRemoteMemoryManager::getMemoryLocationFromElf(
         off_t* offset_in_file) const
 {
     auto shared_libs_it = std::find_if(d_shared_libs.cbegin(), d_shared_libs.cend(), [&](auto& map) {
-        return map.start <= addr && addr <= map.end;
+        return map.start <= addr && addr < map.end;
     });
 
     if (shared_libs_it == d_shared_libs.cend()) {

Original file line number	Diff line number	Diff line change
`@@ -464,7 +464,7 @@ CorefileRemoteMemoryManager::getMemoryLocationFromElf(`
`464`	`464`	`off_t* offset_in_file) const`
`465`	`465`	`{`
`466`	`466`	`auto shared_libs_it = std::find_if(d_shared_libs.cbegin(), d_shared_libs.cend(), [&](auto& map) {`
`467`		`- return map.start <= addr && addr <= map.end;`
	`467`	`+ return map.start <= addr && addr < map.end;`
`468`	`468`	`});`
`469`	`469`
`470`	`470`	`if (shared_libs_it == d_shared_libs.cend()) {`