patch 9.0.1968: cmdline completion should consider key option Commit: https://github.com/vim/vim/commit/6ee7b521fa7531ef356ececc8be7575c3800f872 Author: Yee Cheng Chin <ychin.git@gmail.com> Date: Sun Oct 1 09:13:22 2023 +0200 patch 9.0.1968: cmdline completion should consider key option Problem: cmdline completion should consider key option Solution: Disable cmdline completion for key option, slightly refactor how P_NO_CMD_EXPAND is handled Harden crypto 'key' option: turn off cmdline completion, disable set-= "set-=" can be used maliciously with a crypto key, as it allows an attacker (who either has access to the computer or a plugin author) to guess a substring by observing the modified state. Simply turn off set+=/-=/^= for this option as there is no good reason for them to be used. Update docs to make that clear as well. Also, don't allow cmdline completion for 'key' as it just shows ***** which is not useful and confusing to the user what it means (if the user accidentally hits enter they will have replaced their key with "*****" instead). Move logic to better location, don't use above 32-bit for flags Move P_NO_CMD_EXPAND to use the unused 0x20 instead of going above 32-bits, as currently the flags parameter is only 32-bits on some systems. Left a comment to warn that future additions will need to change how the flags work either by making it 64-bit or split into two member vars. Also, move the logic for detecting P_NO_CMD_EXPAND earlier so it's not up to each handler to decide, and you won't see the temporary "..." that Vim shows while waiting for completion handler to complete. closes: #13224 Signed-off-by: Christian Brabandt <cb@256bit.org> Co-authored-by: Yee Cheng Chin <ychin.git@gmail.com>

--- a/src/optionstr.c
+++ b/src/optionstr.c
@@ -579,7 +579,7 @@ set_string_option(
     }
 #endif
     if ((errmsg = did_set_string_option(opt_idx, varp, oldval, value, errbuf,
-		    opt_flags, &value_checked)) == NULL)
+		    opt_flags, OP_NONE, &value_checked)) == NULL)
 	did_set_option(opt_idx, opt_flags, TRUE, value_checked);
 
 #if defined(FEAT_EVAL)
@@ -1578,6 +1578,10 @@ did_set_cryptkey(optset_T *args)
     // history.
     remove_key_from_history();
 
+    if (args->os_op != OP_NONE)
+	// Don't allow set+=/-=/^= as they can allow for substring guessing
+	return e_invalid_argument;
+
     if (STRCMP(curbuf->b_p_key, args->os_oldval.string) != 0)
     {
 	// Need to update the swapfile.
@@ -4209,6 +4213,7 @@ did_set_string_option(
     char_u	*value,			// new value of the option
     char	*errbuf,		// buffer for errors, or NULL
     int		opt_flags,		// OPT_LOCAL and/or OPT_GLOBAL
+    set_op_T    op,			// OP_ADDING/OP_PREPENDING/OP_REMOVING
     int		*value_checked)		// value was checked to be safe, no
 					// need to set P_INSECURE
 {
@@ -4247,6 +4252,7 @@ did_set_string_option(
 	args.os_varp = (char_u *)varp;
 	args.os_idx = opt_idx;
 	args.os_flags = opt_flags;
+	args.os_op = op;
 	args.os_oldval.string = oldval;
 	args.os_newval.string = value;
 	args.os_errbuf = errbuf;