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crypto: cryptd - Remove VLA usage of skcipher

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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>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Kees Cook 2018-09-18 19:10:52 -07:00 committed by Herbert Xu
parent 8d60539842
commit 36b3875a97
1 changed files with 17 additions and 15 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

32
crypto/cryptd.c
View file

@ -76,7 +76,7 @@ struct cryptd_blkcipher_request_ctx {
struct cryptd_skcipher_ctx { struct cryptd_skcipher_ctx {
atomic_t refcnt; atomic_t refcnt;
struct crypto_skcipher *child; struct crypto_sync_skcipher *child;
}; };
struct cryptd_skcipher_request_ctx { struct cryptd_skcipher_request_ctx {
@ -449,14 +449,16 @@ static int cryptd_skcipher_setkey(struct crypto_skcipher *parent,
const u8 *key, unsigned int keylen) const u8 *key, unsigned int keylen)
{ {
struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(parent); struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(parent);
struct crypto_skcipher *child = ctx->child; struct crypto_sync_skcipher *child = ctx->child;
int err; int err;
crypto_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK); crypto_sync_skcipher_clear_flags(child, CRYPTO_TFM_REQ_MASK);
crypto_skcipher_set_flags(child, crypto_skcipher_get_flags(parent) & crypto_sync_skcipher_set_flags(child,
crypto_skcipher_get_flags(parent) &
CRYPTO_TFM_REQ_MASK); CRYPTO_TFM_REQ_MASK);
err = crypto_skcipher_setkey(child, key, keylen); err = crypto_sync_skcipher_setkey(child, key, keylen);
crypto_skcipher_set_flags(parent, crypto_skcipher_get_flags(child) & crypto_skcipher_set_flags(parent,
crypto_sync_skcipher_get_flags(child) &
CRYPTO_TFM_RES_MASK); CRYPTO_TFM_RES_MASK);
return err; 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 cryptd_skcipher_request_ctx *rctx = skcipher_request_ctx(req);
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm); struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
struct crypto_skcipher *child = ctx->child; struct crypto_sync_skcipher *child = ctx->child;
SKCIPHER_REQUEST_ON_STACK(subreq, child); SYNC_SKCIPHER_REQUEST_ON_STACK(subreq, child);
if (unlikely(err == -EINPROGRESS)) if (unlikely(err == -EINPROGRESS))
goto out; 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, skcipher_request_set_callback(subreq, CRYPTO_TFM_REQ_MAY_SLEEP,
NULL, NULL); NULL, NULL);
skcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen, 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 cryptd_skcipher_request_ctx *rctx = skcipher_request_ctx(req);
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm); struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(tfm);
struct crypto_skcipher *child = ctx->child; struct crypto_sync_skcipher *child = ctx->child;
SKCIPHER_REQUEST_ON_STACK(subreq, child); SYNC_SKCIPHER_REQUEST_ON_STACK(subreq, child);
if (unlikely(err == -EINPROGRESS)) if (unlikely(err == -EINPROGRESS))
goto out; 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, skcipher_request_set_callback(subreq, CRYPTO_TFM_REQ_MAY_SLEEP,
NULL, NULL); NULL, NULL);
skcipher_request_set_crypt(subreq, req->src, req->dst, req->cryptlen, 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)) if (IS_ERR(cipher))
return PTR_ERR(cipher); return PTR_ERR(cipher);
ctx->child = cipher; ctx->child = (struct crypto_sync_skcipher *)cipher;
crypto_skcipher_set_reqsize( crypto_skcipher_set_reqsize(
tfm, sizeof(struct cryptd_skcipher_request_ctx)); tfm, sizeof(struct cryptd_skcipher_request_ctx));
return 0; 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); 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) 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); struct cryptd_skcipher_ctx *ctx = crypto_skcipher_ctx(&tfm->base);
return ctx->child; return &ctx->child->base;
} }
EXPORT_SYMBOL_GPL(cryptd_skcipher_child); EXPORT_SYMBOL_GPL(cryptd_skcipher_child);