[PATCH 7/9] crypto, lz4: Implement zbufsize()

Kees Cook
2018-08-02T21:51:57Z

This implements the worst-case compression size querying interface for
lz4, based on the logic originally used by pstore.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
crypto/lz4.c | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/crypto/lz4.c b/crypto/lz4.c
index 2ce2660d3519..42003d080967 100644
--- a/crypto/lz4.c
+++ b/crypto/lz4.c
@@ -117,6 +117,24 @@ static int lz4_decompress_crypto(struct crypto_tfm *tfm, const u8 *src,
return __lz4_decompress_crypto(src, slen, dst, dlen, NULL);
}

+static int __lz4_zbufsize_crypto(unsigned int slen, unsigned int *dlen)
+{
+ *dlen = LZ4_compressBound(slen);
+ return 0;
+}
+
+static int lz4_szbufsize(struct crypto_scomp *tfm, unsigned int slen,
+ unsigned int *dlen, void *ctx)
+{
+ return __lz4_zbufsize_crypto(slen, dlen);
+}
+
+static int lz4_zbufsize_crypto(struct crypto_tfm *tfm, unsigned int slen,
+ unsigned int *dlen)
+{
+ return __lz4_zbufsize_crypto(slen, dlen);
+}
+
static struct crypto_alg alg_lz4 = {
.cra_name = "lz4",
.cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
@@ -127,7 +145,8 @@ static struct crypto_alg alg_lz4 = {
.cra_exit = lz4_exit,
.cra_u = { .compress = {
.coa_compress = lz4_compress_crypto,
- .coa_decompress = lz4_decompress_crypto } }
+ .coa_decompress = lz4_decompress_crypto,
+ .coa_zbufsize = lz4_zbufsize_crypto } }
};

static struct scomp_alg scomp = {
@@ -135,6 +154,7 @@ static struct scomp_alg scomp = {
.free_ctx = lz4_free_ctx,
.compress = lz4_scompress,
.decompress = lz4_sdecompress,
+ .zbufsize = lz4_szbufsize,
.base = {
.cra_name = "lz4",
.cra_driver_name = "lz4-scomp",
--
2.17.1