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Subject[PATCH crypto-next 15/23] crypto: cryptd - Remove VLA usage of skcipher
Date
In the quest to remove all stack VLA usage from the kernel[1], this
replaces struct crypto_skcipher and SKCIPHER_REQUEST_ON_STACK() usage
with struct crypto_sync_skcipher and SYNC_SKCIPHER_REQUEST_ON_STACK(),
which uses a fixed stack size.

[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com

Signed-off-by: Kees Cook <keescook@chromium.org>
---
crypto/cryptd.c | 32 +++++++++++++++++---------------
1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/crypto/cryptd.c b/crypto/cryptd.c
index addca7bae33f..7118fb5efbaa 100644
--- a/crypto/cryptd.c
+++ b/crypto/cryptd.c
@@ -76,7 +76,7 @@ struct cryptd_blkcipher_request_ctx {

struct cryptd_skcipher_ctx {
atomic_t refcnt;
- struct crypto_skcipher *child;
+ struct crypto_sync_skcipher *child;
};

struct cryptd_skcipher_request_ctx {
@@ -449,14 +449,16 @@ static int cryptd_skcipher_setkey(struct crypto_skcipher *parent,
const u8 *key, unsigned int keylen)
{
struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(parent);
- struct crypto_skcipher *child = ctx->child;
+ struct crypto_sync_skcipher *child = ctx->child;
int err;

- crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
- crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) &
+ crypto_sync_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
+ crypto_sync_skcipher_set_flags(child,
+ crypto_skcipher_get_flags(parent) &
CRYPTO_TFM_REQ_MASK);
- err = crypto_skcipher_setkey(child, key, keylen);
- crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) &
+ err = crypto_sync_skcipher_setkey(child, key, keylen);
+ crypto_skcipher_set_flags(parent,
+ crypto_sync_skcipher_get_flags(child) &
CRYPTO_TFM_RES_MASK);
return err;
}
@@ -483,13 +485,13 @@ static void cryptd_skcipher_encrypt(struct crypto_async_request *base,
struct cryptd_skcipher_request_ctx *rctx = skcipher_request_ctx(req);
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
- struct crypto_skcipher *child = ctx->child;
- SKCIPHER_REQUEST_ON_STACK(subreq, child);
+ struct crypto_sync_skcipher *child = ctx->child;
+ SYNC_SKCIPHER_REQUEST_ON_STACK(subreq, child);

if (unlikely(err == -EINPROGRESS))
goto out;

- skcipher_request_set_tfm(subreq, child);
+ skcipher_request_set_sync_tfm(subreq, child);
skcipher_request_set_callback(subreq, CRYPTO_TFM_REQ_MAY_SLEEP,
NULL, NULL);
skcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
@@ -511,13 +513,13 @@ static void cryptd_skcipher_decrypt(struct crypto_async_request *base,
struct cryptd_skcipher_request_ctx *rctx = skcipher_request_ctx(req);
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
- struct crypto_skcipher *child = ctx->child;
- SKCIPHER_REQUEST_ON_STACK(subreq, child);
+ struct crypto_sync_skcipher *child = ctx->child;
+ SYNC_SKCIPHER_REQUEST_ON_STACK(subreq, child);

if (unlikely(err == -EINPROGRESS))
goto out;

- skcipher_request_set_tfm(subreq, child);
+ skcipher_request_set_sync_tfm(subreq, child);
skcipher_request_set_callback(subreq, CRYPTO_TFM_REQ_MAY_SLEEP,
NULL, NULL);
skcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen,
@@ -568,7 +570,7 @@ static int cryptd_skcipher_init_tfm(struct crypto_skcipher *tfm)
if (IS_ERR(cipher))
return PTR_ERR(cipher);

- ctx->child = cipher;
+ ctx->child = (struct crypto_sync_skcipher *)cipher;
crypto_skcipher_set_reqsize(
tfm, sizeof(struct cryptd_skcipher_request_ctx));
return 0;
@@ -578,7 +580,7 @@ static void cryptd_skcipher_exit_tfm(struct crypto_skcipher *tfm)
{
struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);

- crypto_free_skcipher(ctx->child);
+ crypto_free_sync_skcipher(ctx->child);
}

static void cryptd_skcipher_free(struct skcipher_instance *inst)
@@ -1243,7 +1245,7 @@ struct crypto_skcipher *cryptd_skcipher_child(struct cryptd_skcipher *tfm)
{
struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(&tfm->base);

- return ctx->child;
+ return &ctx->child->base;
}
EXPORT_SYMBOL_GPL(cryptd_skcipher_child);

--
2.17.1
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