For crypto_alg_lookup(), the input parameter combination of mask and type
where both have CRYPTO_ALG_TESTED unset is special in that it is supposed
to be handled as if said flag had been set in both for convenience.
However, the code in crypto_alg_lookup() is not equivalent between these
two cases:
- If CRYPTO_ALG_TESTED is unset in both type and mask, a pending
lookup larval with or without ->CRYPTO_ALG_TESTED being set in its
->mask and ->type can potentially get returned, whereas if
CRYPTO_ALG_TESTED is set in both, only the former is possible.
- If CRYPTO_ALG_TESTED is unset in both type and mask, an error would get
returned if there was one or more matching algorithms which all had
failed their selftests. If OTOH CRYPTO_ALG_TESTED had been set in both
type and mask, NULL would get returned in this case of universal failure
and the caller would proceed to re-request the algorithm in question,
which is not desired.
Even though the first issue is only a cosmetic one and does not affect
functionality in any way AFAICT, addressing it with this patch here will
improve consistency and allow for streamlining crypto_alg_lookup() a bit
later in this series. The second item in the list from above will be left
to a later patch.
Remember that crypto_larval_lookup() will only invoke crypto_larval_add()
if CRYPTO_ALG_TESTED has been set in either none or both of mask and type.
Make crypto_larval_lookup() always set CRYPTO_ALG_TESTED for the mask
and type values passed to crypto_larval_add(). That is, the "issue"
described above is being addressed by sticking to a canonical lookup larval
representation for the two equivalent cases.
There is no change in functionality.
Signed-off-by: Nicolai Stange <nstange@xxxxxxx>
---
crypto/api.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/crypto/api.c b/crypto/api.c
index 3bee52d7fe4b..71406f486c65 100644
--- a/crypto/api.c
+++ b/crypto/api.c
@@ -284,17 +284,17 @@ static struct crypto_alg *crypto_larval_lookup(const char *name, u32 type,
if (!IS_ERR_OR_NULL(alg) && crypto_is_larval(alg))
alg = crypto_larval_wait(alg);
else if (!alg) {
+ if (!(mask & CRYPTO_ALG_TESTED)) {
+ WARN_ON_ONCE((type & CRYPTO_ALG_TESTED));
+ mask |= CRYPTO_ALG_TESTED;
+ type |= CRYPTO_ALG_TESTED;
+ }
+
/*
* Only add a lookup larval if the request is for a
* tested algorithm, everything else makes no sense.
*/
- bool tested = type & mask & CRYPTO_ALG_TESTED;
-
- if (!(mask & CRYPTO_ALG_TESTED)) {
- WARN_ON_ONCE((type & CRYPTO_ALG_TESTED));
- tested = true;
- }
- if (tested)
+ if (type & CRYPTO_ALG_TESTED)
alg = crypto_larval_add(name, type, mask);
else
alg = ERR_PTR(-ENOENT);
--
2.26.2
