lib: parameter check in hash_calculate

If hash_calculate is invoked with region_count = 0, it will try to hash
INT_MAX regions. We should check this parameter.

* Avoid a comparison with different signedness.
* Check that region_count is at least 1.
* Avoid a superfluous assignment.

Fixes: b37b46f042cc ("rsa: Use checksum algorithms from struct hash_algo")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/lib/hash-checksum.c b/lib/hash-checksum.c
index 8f2a42f..68c290d 100644 (file)
--- a/lib/hash-checksum.c
+++ b/lib/hash-checksum.c
@@ -23,8 +23,10 @@ int hash_calculate(const char *name,
        struct hash_algo *algo;
        int ret = 0;
        void *ctx;
-       uint32_t i;
-       i = 0;
+       int i;
+
+       if (region_count < 1)
+               return -EINVAL;
 
        ret = hash_progressive_lookup_algo(name, &algo);
        if (ret)