[PATCH 3/9] crypto, null: Implement zbufsize()

Kees Cook
2018-08-02T21:51:28Z

This implements the worst-case compression size querying interface for
the "null" compression implementation (i.e. no change in size).

Signed-off-by: Kees Cook <keescook@chromium.org>
---
crypto/crypto_null.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/crypto/crypto_null.c b/crypto/crypto_null.c
index 20ff2c746e0b..d1b6107f8443 100644
--- a/crypto/crypto_null.c
+++ b/crypto/crypto_null.c
@@ -39,6 +39,13 @@ static int null_compress(struct crypto_tfm *tfm, const u8 *src,
return 0;
}

+static int null_zbufsize(struct crypto_tfm *tfm, unsigned int slen,
+ unsigned int *dlen)
+{
+ *dlen = slen;
+ return 0;
+}
+
static int null_init(struct shash_desc *desc)
{
return 0;
@@ -146,7 +153,8 @@ static struct crypto_alg null_algs[3] = { {
.cra_module = THIS_MODULE,
.cra_u = { .compress = {
.coa_compress = null_compress,
- .coa_decompress = null_compress } }
+ .coa_decompress = null_compress,
+ .coa_zbufsize = null_zbufsize } }
} };

MODULE_ALIAS_CRYPTO("compress_null");
--
2.17.1