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| author | Nicolai Stange <nstange@suse.de> | 2022-02-21 13:10:58 +0100 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2022-03-03 10:47:51 +1200 |
| commit | d6097b8d5d55f26cd2244e7e7f00a5a077772a91 (patch) | |
| tree | df3f12fb9468f0058aaff47a5466c0bd53ef1a17 /crypto/api.c | |
| parent | c8e8236cf71f1e808120804339d2c23dc304f9cd (diff) | |
| download | linux-d6097b8d5d55f26cd2244e7e7f00a5a077772a91.tar.gz | |
crypto: api - allow algs only in specific constructions in FIPS mode
Currently we do not distinguish between algorithms that fail on the self-test vs. those which are disabled in FIPS mode (not allowed). Both are marked as having failed the self-test. Recently the need arose to allow the usage of certain algorithms only as arguments to specific template instantiations in FIPS mode. For example, standalone "dh" must be blocked, but e.g. "ffdhe2048(dh)" is allowed. Other potential use cases include "cbcmac(aes)", which must only be used with ccm(), or "ghash", which must be used only for gcm(). This patch allows this scenario by adding a new flag FIPS_INTERNAL to indicate those algorithms that are not FIPS-allowed. They can then be used as template arguments only, i.e. when looked up via crypto_grab_spawn() to be more specific. The FIPS_INTERNAL bit gets propagated upwards recursively into the surrounding template instances, until the construction eventually matches an explicit testmgr entry with ->fips_allowed being set, if any. The behaviour to skip !->fips_allowed self-test executions in FIPS mode will be retained. Note that this effectively means that FIPS_INTERNAL algorithms are handled very similarly to the INTERNAL ones in this regard. It is expected that the FIPS_INTERNAL algorithms will receive sufficient testing when the larger constructions they're a part of, if any, get exercised by testmgr. Note that as a side-effect of this patch algorithms which are not FIPS-allowed will now return ENOENT instead of ELIBBAD. Hopefully this is not an issue as some people were relying on this already. Link: https://lore.kernel.org/r/YeEVSaMEVJb3cQkq@gondor.apana.org.au Originally-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Nicolai Stange <nstange@suse.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto/api.c')
| -rw-r--r-- | crypto/api.c | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/crypto/api.c b/crypto/api.c index cf0869dd130b..549f9aced1da 100644 --- a/crypto/api.c +++ b/crypto/api.c @@ -223,6 +223,8 @@ static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg) else if (crypto_is_test_larval(larval) && !(alg->cra_flags & CRYPTO_ALG_TESTED)) alg = ERR_PTR(-EAGAIN); + else if (alg->cra_flags & CRYPTO_ALG_FIPS_INTERNAL) + alg = ERR_PTR(-EAGAIN); else if (!crypto_mod_get(alg)) alg = ERR_PTR(-EAGAIN); crypto_mod_put(&larval->alg); @@ -233,6 +235,7 @@ static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg) static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, u32 mask) { + const u32 fips = CRYPTO_ALG_FIPS_INTERNAL; struct crypto_alg *alg; u32 test = 0; @@ -240,8 +243,20 @@ static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type, test |= CRYPTO_ALG_TESTED; down_read(&crypto_alg_sem); - alg = __crypto_alg_lookup(name, type | test, mask | test); - if (!alg && test) { + alg = __crypto_alg_lookup(name, (type | test) & ~fips, + (mask | test) & ~fips); + if (alg) { + if (((type | mask) ^ fips) & fips) + mask |= fips; + mask &= fips; + + if (!crypto_is_larval(alg) && + ((type ^ alg->cra_flags) & mask)) { + /* Algorithm is disallowed in FIPS mode. */ + crypto_mod_put(alg); + alg = ERR_PTR(-ENOENT); + } + } else if (test) { alg = __crypto_alg_lookup(name, type, mask); if (alg && !crypto_is_larval(alg)) { /* Test failed */ |