[Openmp-commits] [openmp] [OpenMP] Fix a potential memory buffer overflow (PR #67252)

[Shilei Tian via Openmp-commits]

https://github.com/shiltian created https://github.com/llvm/llvm-project/pull/67252

to the function `memcpy_s`. This patch fixes it.

Fix #67167.


>From 5aa7b21eaa3a62d79921ce1374a39c8594b82f26 Mon Sep 17 00:00:00 2001
From: Shilei Tian <i at tianshilei.me>
Date: Sat, 23 Sep 2023 22:46:09 -0400
Subject: [PATCH] [OpenMP] Fix a potential memory buffer overflow

to the function `memcpy_s`. This patch fixes it.

Fix #67167.
---
 openmp/runtime/src/kmp_environment.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/openmp/runtime/src/kmp_environment.cpp b/openmp/runtime/src/kmp_environment.cpp
index b35027b57f03db0..4def6ea9ac20943 100644
--- a/openmp/runtime/src/kmp_environment.cpp
+++ b/openmp/runtime/src/kmp_environment.cpp
@@ -407,9 +407,11 @@ ___kmp_env_blk_parse_unix(kmp_env_blk_t *block, // M: Env block to fill.
     int i;
     var = bulk;
     for (i = 0; i < count; ++i) {
+      KMP_ASSERT(var < bulk + size);
+      [[maybe_unused]] size_t ssize = size - (var - bulk);
       // Copy variable to bulk.
       len = KMP_STRLEN(env[i]);
-      KMP_MEMCPY_S(var, size, env[i], len + 1);
+      KMP_MEMCPY_S(var, ssize, env[i], len + 1);
       // Save found variable in vars array.
       __kmp_str_split(var, '=', &name, &value);
       vars[i].name = name;