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

[Kees Cook]

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

Signed-off-by: Kees Cook <keesc...@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