dm verity: fix verity_parse_opt_args parsing

Commit df326e7a0699 ("dm verity: allow optional args to alter primary
args handling") introduced a bug where verity_parse_opt_args() wouldn't
properly shift past an optional argument's additional params (by
ignoring them).

Fix this by avoiding returning with error if an unknown argument is
encountered when @only_modifier_opts=true is passed to
verity_parse_opt_args().

In practice this regressed the cryptsetup testsuite's FEC testing
because unknown optional arguments were encountered, wherey
short-circuiting ever testing FEC mode. With this fix all of the
cryptsetup testsuite's verity FEC tests pass.

Fixes: df326e7a0699 ("dm verity: allow optional args to alter primary args handling")
Reported-by: Milan Broz <gmazyland@gmail.com>>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>

diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index 5b9062e5167b1e2d258834e383d560c6268b99d1..0d70c9c60d463908df6c1ed03ba24a32f63a7aa8 100644 (file)
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -1052,7 +1052,7 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
                                 struct dm_verity_sig_opts *verify_args,
                                 bool only_modifier_opts)
 {
-       int r;
+       int r = 0;
        unsigned argc;
        struct dm_target *ti = v->ti;
        const char *arg_name;
@@ -1122,8 +1122,18 @@ static int verity_parse_opt_args(struct dm_arg_set *as, struct dm_verity *v,
                        if (r)
                                return r;
                        continue;
+
+               } else if (only_modifier_opts) {
+                       /*
+                        * Ignore unrecognized opt, could easily be an extra
+                        * argument to an option whose parsing was skipped.
+                        * Normal parsing (@only_modifier_opts=false) will
+                        * properly parse all options (and their extra args).
+                        */
+                       continue;
                }
 
+               DMERR("Unrecognized verity feature request: %s", arg_name);
                ti->error = "Unrecognized verity feature request";
                return -EINVAL;
        } while (argc && !r);