Standardise how to interpret a partial byte

Signed-off-by: Mattias Andrée <maandree@kth.se>

1 files changed, 6 insertions, 2 deletions

diff --git a/libhashsum_init_md4_hasher.c b/libhashsum_init_md4_hasher.c
index c51ebf8..f3c26ac 100644
--- a/libhashsum_init_md4_hasher.c
+++ b/libhashsum_init_md4_hasher.c
@@ -98,10 +98,12 @@ finalise_common(struct libhashsum_hasher *this, uint8_t *m, size_t bytes, unsign
 	this->state.md4.count *= 8U;
 	this->state.md4.count += (size_t)extra_bits;
 
-	memset(&m[bytes], 0, 64U - bytes);
+	if (extra_bits)
+		m[bytes] = libhashsum_reverse_byte__(m[bytes]);
+	memset(&m[bytes + 1U], 0, 63U - bytes);
 	mask = (uint8_t)(1U << (7U - extra_bits));
 	m[bytes] |= mask;
-	m[bytes] &= (uint8_t)~(mask - 1U); /* keep high bits */
+	m[bytes] &= (uint8_t)~(mask - 1U); /* keep high bits (original value was reversed) */
 	for (i = 0; i < 14; i++)
 		this->state.md4.m.m32[i] = LETO32(&m[i * 4U]);
 
@@ -143,6 +145,7 @@ finalise_const(struct libhashsum_hasher *this, const void *data, size_t bytes, u
 	m = &m[r];
 	bytes -= r;
 
+	this->state.md4.m.m8[bytes] = 0;
 	memcpy(this->state.md4.m.m8, m, bytes + (size_t)(extra_bits > 0U));
 	return finalise_common(this, this->state.md4.m.m8, bytes, extra_bits);
 }
@@ -161,6 +164,7 @@ finalise(struct libhashsum_hasher *this, void *data, size_t bytes, unsigned extr
 	size -= r;
 
 	if (size < 64U) {
+		this->state.md4.m.m8[bytes] = 0;
 		memcpy(this->state.md4.m.m8, m, bytes + (size_t)(extra_bits > 0U));
 		m = this->state.md4.m.m8;
 	}