Escape config vars when expanding hook "command" argument.

The "command" parameter of folder, send, send2, account, reply, and
message hooks is run through mutt_extract_token() twice.  Once when
parsing the hook command initially, and once via mutt_parse_rc_line()
when the actual hook fires.

In theory, Mutt users should be aware of this, and should place all
their command strings with configuration variables in single-quotes,
to delay expansion until execution.

But in reality Mutt has been escaping configuration variables as part
of mutt_extract_token() for many years.

The previous commit turned the escaping off, because it damages
"backup" assignments to a $my_ variable, and I believe is confusing
behavior.

But for hooks, users now expect the escaping behavior (for
double-quoted or unquoted command strings).

Note that mutt_parse_hook() also passed the MUTT_TOKEN_SPACE flag, but
neglected to do so for message-hook.  Since all other "command"
argument hooks were included, and were added to the list over the
years, I believe this was an accidental oversight.

1 files changed, 43 insertions, 1 deletions

diff --git a/init.c b/init.c
index 499eefd7..ef83648a 100644
--- a/init.c
+++ b/init.c
@@ -72,6 +72,7 @@ typedef struct myvar
 static myvar_t* MyVars;
 
 static int var_to_string (int idx, BUFFER *val);
+static void escape_string_to_buffer (BUFFER *dst, const char *src);
 
 static void myvar_set (const char* var, const char* val);
 static const char* myvar_get (const char* var);
@@ -311,7 +312,18 @@ int mutt_extract_token (BUFFER *dest, BUFFER *tok, int flags)
           BUFFER *val = mutt_buffer_pool_get ();
 
           if (var_to_string (idx, val))
-            mutt_buffer_addstr (dest, mutt_b2s (val));
+          {
+            if (flags & MUTT_TOKEN_ESC_VARS)
+            {
+              BUFFER *escval = mutt_buffer_pool_get ();
+
+              escape_string_to_buffer (escval, mutt_b2s (val));
+              mutt_buffer_addstr (dest, mutt_b2s (escval));
+              mutt_buffer_pool_release (&escval);
+            }
+            else
+              mutt_buffer_addstr (dest, mutt_b2s (val));
+          }
           mutt_buffer_pool_release (&val);
         }
         FREE (&var);
@@ -1888,6 +1900,36 @@ static void mutt_restore_default (struct option_t *p)
     mutt_set_current_menu_redraw_full ();
 }
 
+static void escape_string_to_buffer (BUFFER *dst, const char *src)
+{
+  mutt_buffer_clear (dst);
+
+  if (!src || !*src)
+    return;
+
+  for (; *src; src++)
+  {
+    switch (*src)
+    {
+      case '\n':
+        mutt_buffer_addstr (dst, "\\n");
+        break;
+      case '\r':
+        mutt_buffer_addstr (dst, "\\r");
+        break;
+      case '\t':
+        mutt_buffer_addstr (dst, "\\t");
+        break;
+      case '\\':
+      case '"':
+        mutt_buffer_addch (dst, '\\');
+        /* fall through */
+      default:
+        mutt_buffer_addch (dst, *src);
+    }
+  }
+}
+
 static size_t escape_string (char *dst, size_t len, const char* src)
 {
   char* p = dst;