3 files changed, 29 insertions, 5 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 267493708..578b3dc22 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -5651,6 +5651,10 @@ rmescapes(char *str, int flag)
                 }
                 if ((unsigned char)*p == CTLESC) {
                         p++;
+#if DEBUG
+                        if (*p == '\0')
+                                ash_msg_and_raise_error("CTLESC at EOL (shouldn't happen)");
+#endif
                         if (protect_against_glob) {
                                 *q++ = '\\';
                         }
@@ -11302,20 +11306,24 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
                         USTPUTC(c, out);
                         break;
                 case CCTL:
-                        if (eofmark == NULL || dblquote)
-                                USTPUTC(CTLESC, out);
 #if ENABLE_ASH_BASH_COMPAT
                         if (c == '\\' && bash_dollar_squote) {
                                 c = decode_dollar_squote();
+                                if (c == '\0') {
+                                        /* skip $'\000', $'\x00' (like bash) */
+                                        break;
+                                }
                                 if (c & 0x100) {
-                                        USTPUTC('\\', out);
+                                        /* Unknown escape. Encode as '\z' */
+                                        c = (unsigned char)c;
                                         if (eofmark == NULL || dblquote)
-                                                /* Or else this SEGVs: $'\<0x82>' */
                                                 USTPUTC(CTLESC, out);
-                                        c = (unsigned char)c;
+                                        USTPUTC('\\', out);
                                 }
                         }
 #endif
+                        if (eofmark == NULL || dblquote)
+                                USTPUTC(CTLESC, out);
                         USTPUTC(c, out);
                         break;
                 case CBACK:     /* backslash */
diff --git a/shell/ash_test/ash-quoting/dollar_squote_bash2.right b/shell/ash_test/ash-quoting/dollar_squote_bash2.right
new file mode 100644
index 000000000..f7a1731dd
--- /dev/null
+++ b/shell/ash_test/ash-quoting/dollar_squote_bash2.right
@@ -0,0 +1,6 @@
+strstrstrstrstrstrstrstrstrstrstrstrstrstrstrstrstr
+strstrstrstrstrstrstrstrstrstrstrstrstrstrstrstrstr
+80:\�
+81:\�
+82:\�
+Done:0
diff --git a/shell/ash_test/ash-quoting/dollar_squote_bash2.tests b/shell/ash_test/ash-quoting/dollar_squote_bash2.tests
new file mode 100755
index 000000000..449772813
--- /dev/null
+++ b/shell/ash_test/ash-quoting/dollar_squote_bash2.tests
@@ -0,0 +1,10 @@
+# Embedded NULs
+echo $'str\x00'strstrstrstrstrstrstrstrstrstrstrstrstrstrstrstr
+echo $'str\000'strstrstrstrstrstrstrstrstrstrstrstrstrstrstrstr
+
+# The chars after '\' are hex 0x80,81,82...
+echo 80:$'\�'
+echo 81:$'\�'
+echo 82:$'\�'
+
+echo Done:$?