From: Eric Biggers <ebiggers@xxxxxxxxxx>
Since commit adad556efcdd ("crypto: api - Fix built-in testing
dependency failures"), the following warning appears when booting an
x86_64 kernel that is configured with
CONFIG_CRYPTO_MANAGER_EXTRA_TESTS=y and CONFIG_CRYPTO_AES_NI_INTEL=y,
even when CONFIG_CRYPTO_XTS=y and CONFIG_CRYPTO_AES=y:
alg: skcipher: skipping comparison tests for xts-aes-aesni because xts(ecb(aes-generic)) is unavailable
This is caused by an issue in the xts template where it allocates an
"aes" single-block cipher without declaring a dependency on it via the
crypto_spawn mechanism. This issue was exposed by the above commit
because it reversed the order that the algorithms are tested in.
Specifically, when "xts(ecb(aes-generic))" is instantiated and tested
during the comparison tests for "xts-aes-aesni", the "xts" template
allocates an "aes" crypto_cipher for encrypting tweaks. This resolves
to "aes-aesni". (Getting "aes-aesni" instead of "aes-generic" here is a
bit weird, but it's apparently intended.) Due to the above-mentioned
commit, the testing of "aes-aesni", and the finalization of its
registration, now happens at this point instead of before. At the end
of that, crypto_remove_spawns() unregisters all algorithm instances that
depend on a lower-priority "aes" implementation such as "aes-generic"
but that do not depend on "aes-aesni". However, because "xts" does not
use the crypto_spawn mechanism for its "aes", its dependency on
"aes-aesni" is not recognized by crypto_remove_spawns(). Thus,
crypto_remove_spawns() unexpectedly unregisters "xts(ecb(aes-generic))".
Fix this issue by making the "xts" template use the crypto_spawn
mechanism for its "aes" dependency, like what other templates do.
Note, this fix could be applied as far back as commit f1c131b45410
("crypto: xts - Convert to skcipher"). However, the issue only got
exposed by the much more recent changes to how the crypto API runs the
self-tests, so there should be no need to backport this to very old
kernels. Also, an alternative fix would be to flip the list iteration
order in crypto_start_tests() to restore the original testing order.
I'm thinking we should do that too, since the original order seems more
natural, but it shouldn't be relied on for correctness.
Fixes: adad556efcdd ("crypto: api - Fix built-in testing dependency failures")
Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>
---
crypto/xts.c | 23 +++++++++++++++--------
1 file changed, 15 insertions(+), 8 deletions(-)
diff --git a/crypto/xts.c b/crypto/xts.c
index 548b302c6c6a0..2cabf9e657868 100644
--- a/crypto/xts.c
+++ b/crypto/xts.c
@@ -21,21 +21,21 @@
#include <crypto/b128ops.h>
#include <crypto/gf128mul.h>
struct xts_tfm_ctx {
struct crypto_skcipher *child;
struct crypto_cipher *tweak;
};
struct xts_instance_ctx {
struct crypto_skcipher_spawn spawn;
- char name[CRYPTO_MAX_ALG_NAME];
+ struct crypto_cipher_spawn tweak_spawn;
};
struct xts_request_ctx {
le128 t;
struct scatterlist *tail;
struct scatterlist sg[2];
struct skcipher_request subreq;
};
static int xts_setkey(struct crypto_skcipher *parent, const u8 *key,
@@ -299,21 +299,21 @@ static int xts_init_tfm(struct crypto_skcipher *tfm)
struct xts_tfm_ctx *ctx = crypto_skcipher_ctx(tfm);
struct crypto_skcipher *child;
struct crypto_cipher *tweak;
child = crypto_spawn_skcipher(&ictx->spawn);
if (IS_ERR(child))
return PTR_ERR(child);
ctx->child = child;
- tweak = crypto_alloc_cipher(ictx->name, 0, 0);
+ tweak = crypto_spawn_cipher(&ictx->tweak_spawn);
if (IS_ERR(tweak)) {
crypto_free_skcipher(ctx->child);
return PTR_ERR(tweak);
}
ctx->tweak = tweak;
crypto_skcipher_set_reqsize(tfm, crypto_skcipher_reqsize(child) +
sizeof(struct xts_request_ctx));
@@ -326,29 +326,31 @@ static void xts_exit_tfm(struct crypto_skcipher *tfm)
crypto_free_skcipher(ctx->child);
crypto_free_cipher(ctx->tweak);
}
static void xts_free_instance(struct skcipher_instance *inst)
{
struct xts_instance_ctx *ictx = skcipher_instance_ctx(inst);
crypto_drop_skcipher(&ictx->spawn);
+ crypto_drop_cipher(&ictx->tweak_spawn);
kfree(inst);
}
static int xts_create(struct crypto_template *tmpl, struct rtattr **tb)
{
struct skcipher_instance *inst;
struct xts_instance_ctx *ctx;
struct skcipher_alg *alg;
const char *cipher_name;
+ char name[CRYPTO_MAX_ALG_NAME];
u32 mask;
int err;
err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_SKCIPHER, &mask);
if (err)
return err;
cipher_name = crypto_attr_alg_name(tb[1]);
if (IS_ERR(cipher_name))
return PTR_ERR(cipher_name);
@@ -356,27 +358,27 @@ static int xts_create(struct crypto_template *tmpl, struct rtattr **tb)
inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
if (!inst)
return -ENOMEM;
ctx = skcipher_instance_ctx(inst);
err = crypto_grab_skcipher(&ctx->spawn, skcipher_crypto_instance(inst),
cipher_name, 0, mask);
if (err == -ENOENT) {
err = -ENAMETOOLONG;
- if (snprintf(ctx->name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
+ if (snprintf(name, CRYPTO_MAX_ALG_NAME, "ecb(%s)",
cipher_name) >= CRYPTO_MAX_ALG_NAME)
goto err_free_inst;
err = crypto_grab_skcipher(&ctx->spawn,
skcipher_crypto_instance(inst),
- ctx->name, 0, mask);
+ name, 0, mask);
}
if (err)
goto err_free_inst;
alg = crypto_skcipher_spawn_alg(&ctx->spawn);
err = -EINVAL;
if (alg->base.cra_blocksize != XTS_BLOCK_SIZE)
goto err_free_inst;
@@ -391,37 +393,42 @@ static int xts_create(struct crypto_template *tmpl, struct rtattr **tb)
err = -EINVAL;
cipher_name = alg->base.cra_name;
/* Alas we screwed up the naming so we have to mangle the
* cipher name.
*/
if (!strncmp(cipher_name, "ecb(", 4)) {
int len;
- len = strscpy(ctx->name, cipher_name + 4, sizeof(ctx->name));
+ len = strscpy(name, cipher_name + 4, sizeof(name));
if (len < 2)
goto err_free_inst;
- if (ctx->name[len - 1] != ')')
+ if (name[len - 1] != ')')
goto err_free_inst;
- ctx->name[len - 1] = 0;
+ name[len - 1] = 0;
if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
- "xts(%s)", ctx->name) >= CRYPTO_MAX_ALG_NAME) {
+ "xts(%s)", name) >= CRYPTO_MAX_ALG_NAME) {
err = -ENAMETOOLONG;
goto err_free_inst;
}
} else
goto err_free_inst;
+ err = crypto_grab_cipher(&ctx->tweak_spawn,
+ skcipher_crypto_instance(inst), name, 0, mask);
+ if (err)
+ goto err_free_inst;
+
inst->alg.base.cra_priority = alg->base.cra_priority;
inst->alg.base.cra_blocksize = XTS_BLOCK_SIZE;
inst->alg.base.cra_alignmask = alg->base.cra_alignmask |
(__alignof__(u64) - 1);
inst->alg.ivsize = XTS_BLOCK_SIZE;
inst->alg.min_keysize = crypto_skcipher_alg_min_keysize(alg) * 2;
inst->alg.max_keysize = crypto_skcipher_alg_max_keysize(alg) * 2;
inst->alg.base.cra_ctxsize = sizeof(struct xts_tfm_ctx);
base-commit: 8468516f9f93a41dc65158b6428a1a1039c68f20
--
2.42.0
