Re: [PATCH RESEND] KEYS: fix parsing invalid pkey info string

[Linus Torvalds]

On Mon, Dec 17, 2018 at 11:06 AM Linus Torvalds
<torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> Honestly, for being about "security", all of this code seems to be
> doing some really questionable things with all those Opt_xyz enums.

Yeah, at least security/keys/trusted.c ends up mixing that enum and
just using "int" completely randomly, and you have datablob_parse()
returning either a negative integer _or_ an "Opt_xyz" value, so having
Opt_err be -1 is doubly confusing there (it would also be "-EPERM"
depending on how you treat it).

There doesn't seem to be any _actual_ confusion (because Opt_err is
always turned into an actual real error code), but it's  just another
sign of "those enums should not be negative".

So on the whole, I think that the "Opt_err = -1" is a serious mistake,
but at least for now, ima_policy.c clearly has (bogus) code that
relies on it.

But the two cases that use "test_and_set_bit()" do not seem to have
any reason to use that -1 enum, so while we can't do the "just remove
-1" in general, I do think the proper fix is to just do it for those
two files.

Eric, mind testing a patch like that? Untested patch attached just for
completeness..

                    Linus
 security/keys/keyctl_pkey.c | 2 +-
 security/keys/trusted.c     | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/security/keys/keyctl_pkey.c b/security/keys/keyctl_pkey.c
index 783978842f13..70e65a2ff207 100644
--- a/security/keys/keyctl_pkey.c
+++ b/security/keys/keyctl_pkey.c
@@ -25,7 +25,7 @@ static void keyctl_pkey_params_free(struct kernel_pkey_params *params)
 }
 
 enum {
-	Opt_err = -1,
+	Opt_err,
 	Opt_enc,		/* "enc=<encoding>" eg. "enc=oaep" */
 	Opt_hash,		/* "hash=<digest-name>" eg. "hash=sha1" */
 };
diff --git a/security/keys/trusted.c b/security/keys/trusted.c
index ff6789365a12..697bfc6c8192 100644
--- a/security/keys/trusted.c
+++ b/security/keys/trusted.c
@@ -711,7 +711,7 @@ static int key_unseal(struct trusted_key_payload *p,
 }
 
 enum {
-	Opt_err = -1,
+	Opt_err,
 	Opt_new, Opt_load, Opt_update,
 	Opt_keyhandle, Opt_keyauth, Opt_blobauth,
 	Opt_pcrinfo, Opt_pcrlock, Opt_migratable,