1 files changed, 8 insertions, 2 deletions

diff --git a/shell/ash.c b/shell/ash.c
index f23a3e1ff..80846da0f 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -13471,10 +13471,16 @@ init(void)
                                 if (!(end=strchr(*envp, '=')))
                                         continue;
 
-                                /* make all variable names uppercase */
-                                for (start = *envp;start < end;start++)
+                                for (start = *envp;start < end;start++) {
+                                        /* make all variable names uppercase */
                                         *start = toupper(*start);
 
+                                        /* replace invalid characters with underscores */
+                                        if (!isdigit(*start) && !isalpha(*start) && *start != '_') {
+                                                *start = '_';
+                                        }
+                                }
+
                                 /* skip conversion of variables known to cause problems */
                                 if ( strncmp(*envp, "SYSTEMROOT=", 11) == 0 ||
                                                 strncmp(*envp, "COMSPEC=", 8) == 0 ) {