| Message ID | E1pzvTZ-00AnMQ-5M@formenos.hmeau.com |
|---|---|
| State | Accepted |
| Commit | ed51bba18f563594b5ddf7aaa5fd61abe5e474ae |
| Headers | show |
| Series | crypto: cmac - Add cloning support | expand |
On Fri, May 19, 2023 at 11:31:30AM +0200, Ard Biesheuvel wrote: > > OK. So IIUC, cloning a keyless hash just shares the TFM and bumps the > refcount, but here we must actually allocate a new TFM referring to > the same algo, and this new TFM needs its key to be set before use, as > it doesn't inherit it from the clonee, right? And this works in the > same way as cloning an instance of the generic HMAC template, as this > will just clone the inner shash too, and will also leave the key > unset. Yes that's pretty much it. Cloning a tfm is basically exactly the same as allocating a tfm, except that instead of going through the init_tfm code-path it executes clone_tfm instead (thus allowing any internal data structures to either be shared or allocated with GFP_ATOMIC). The key will be unset just like a freshly allocated tfm. > If so, > > Acked-by: Ard Biesheuvel <ardb@kernel.org> Thanks,
Hi Herbert, Thanks for the patches! On 5/19/23 09:28, Herbert Xu wrote: > Allow hmac to be cloned. The underlying cipher needs to support Small nit ^cmac > cloning by not having a cra_init function (all implementations of > aes that do not require a fallback can be cloned). > > Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> I'll remove per-CPU request allocations and base version7 on this. Thanks, Dmitry
diff --git a/crypto/cmac.c b/crypto/cmac.c index bcc6f19a4f64..fce6b0f58e88 100644 --- a/crypto/cmac.c +++ b/crypto/cmac.c @@ -213,7 +213,22 @@ static int cmac_init_tfm(struct crypto_shash *tfm) ctx->child = cipher; return 0; -}; +} + +static int cmac_clone_tfm(struct crypto_shash *tfm, struct crypto_shash *otfm) +{ + struct cmac_tfm_ctx *octx = crypto_shash_ctx(otfm); + struct cmac_tfm_ctx *ctx = crypto_shash_ctx(tfm); + struct crypto_cipher *cipher; + + cipher = crypto_clone_cipher(octx->child); + if (IS_ERR(cipher)) + return PTR_ERR(cipher); + + ctx->child = cipher; + + return 0; +} static void cmac_exit_tfm(struct crypto_shash *tfm) { @@ -280,6 +295,7 @@ static int cmac_create(struct crypto_template *tmpl, struct rtattr **tb) inst->alg.final = crypto_cmac_digest_final; inst->alg.setkey = crypto_cmac_digest_setkey; inst->alg.init_tfm = cmac_init_tfm; + inst->alg.clone_tfm = cmac_clone_tfm; inst->alg.exit_tfm = cmac_exit_tfm; inst->free = shash_free_singlespawn_instance;
Allow hmac to be cloned. The underlying cipher needs to support cloning by not having a cra_init function (all implementations of aes that do not require a fallback can be cloned). Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> --- crypto/cmac.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-)