[PATCH 4/9] crypto, lzo: Implement zbufsize()

Kees Cook
2018-08-02T21:51:31Z

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

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

diff --git a/crypto/lzo.c b/crypto/lzo.c
index 218567d717d6..ea18f62c5247 100644
--- a/crypto/lzo.c
+++ b/crypto/lzo.c
@@ -120,6 +120,24 @@ static int lzo_sdecompress(struct crypto_scomp *tfm, const u8 *src,
return __lzo_decompress(src, slen, dst, dlen);
}

+static int __lzo_zbufsize(unsigned int slen, unsigned int *dlen)
+{
+ *dlen = lzo1x_worst_compress(slen);
+ return 0;
+}
+
+static int lzo_zbufsize(struct crypto_tfm *tfm, unsigned int slen,
+ unsigned int *dlen)
+{
+ return __lzo_zbufsize(slen, dlen);
+}
+
+static int lzo_szbufsize(struct crypto_scomp *tfm, unsigned int slen,
+ unsigned int *dlen, void *ctx)
+{
+ return __lzo_zbufsize(slen, dlen);
+}
+
static struct crypto_alg alg = {
.cra_name = "lzo",
.cra_flags = CRYPTO_ALG_TYPE_COMPRESS,
@@ -129,7 +147,8 @@ static struct crypto_alg alg = {
.cra_exit = lzo_exit,
.cra_u = { .compress = {
.coa_compress = lzo_compress,
- .coa_decompress = lzo_decompress } }
+ .coa_decompress = lzo_decompress,
+ .coa_zbufsize = lzo_zbufsize } }
};

static struct scomp_alg scomp = {
@@ -137,6 +156,7 @@ static struct scomp_alg scomp = {
.free_ctx = lzo_free_ctx,
.compress = lzo_scompress,
.decompress = lzo_sdecompress,
+ .zbufsize = lzo_szbufsize,
.base = {
.cra_name = "lzo",
.cra_driver_name = "lzo-scomp",
--
2.17.1