[PATCH] D112998: [sanitizer_common] Fix readlink error handling in sanitizer_procmaps_solaris.cpp

[Rainer Orth via Phabricator via llvm-commits]

ro created this revision.
ro added a reviewer: vitalybuka.
ro added a project: Sanitizers.
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As Rich Lowe pointed out in Bug 52371, the Solaris version of `MemoryMappingLayout::Next` completely failed to handle `readlink` errors or properly
NUL-terminate the result.

This patch fixes this.  Originally provided in the PR with slight formatting changes.

Tested on `amd64-pc-solaris2.11`.

I'm uncertain how to properly attribute the patch on commit, though.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D112998

Files:
  compiler-rt/lib/sanitizer_common/sanitizer_procmaps_solaris.cpp


Index: compiler-rt/lib/sanitizer_common/sanitizer_procmaps_solaris.cpp
===================================================================
--- compiler-rt/lib/sanitizer_common/sanitizer_procmaps_solaris.cpp
+++ compiler-rt/lib/sanitizer_common/sanitizer_procmaps_solaris.cpp
@@ -55,7 +55,15 @@
 
     internal_snprintf(proc_path, sizeof(proc_path), "/proc/self/path/%s",
                       xmapentry->pr_mapname);
-    internal_readlink(proc_path, segment->filename, segment->filename_size);
+    ssize_t sz = internal_readlink(proc_path, segment->filename,
+                                   segment->filename_size - 1);
+
+    // If readlink failed, the map is anonymous.
+    if (sz == -1) {
+      segment->filename[0] = '\0';
+    } else if ((size_t)sz < segment->filename_size)
+      // readlink doesn't NUL-terminate.
+      segment->filename[sz] = '\0';
   }
 
   data_.current += sizeof(prxmap_t);


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