From 389f4f8b16dc1cf159a78e8366f9a5cdf92fdf2d Mon Sep 17 00:00:00 2001
From: Kitibodee Phuphanwoe <kitibodee.ph@ksu.ac.th>
Date: Tue, 19 Aug 2025 22:02:13 +0700
Subject: [PATCH] Improved SHMEM_SYMMETRIC_SIZE Validation

Issue #1185

If SHMEM_SYMMETRIC_SIZE contains invalid characters, return error.

Signed-off-by: Kitibodee Phuphanwoe <kitibodee.ph@ksu.ac.th>
---
 src/shmem_env.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/shmem_env.c b/src/shmem_env.c
index af3a6e733..035960855 100644
--- a/src/shmem_env.c
+++ b/src/shmem_env.c
@@ -38,9 +38,12 @@ atol_scaled(char *str, shmem_internal_env_size *out)
     double p = -1.0;
     char f;
 
-    n = sscanf(str, "%lf%c", &p, &f);
+    if (2 == sscanf(str, "%lf%c%n", &p, &f, &n)) {
+        if (str[n] != '\0') {
+            fprintf(stderr, "Invalid size in environment variable\n");
+            return 1;
+        }
 
-    if (n == 2) {
         switch (f) {
             case 'k':
             case 'K':