diff --git a/lib/internal.h b/lib/internal.h
index 690ecbfc..35d03a41 100644
--- a/lib/internal.h
+++ b/lib/internal.h
@@ -106,7 +106,7 @@ ssize_t read_buffer(int fd, void *buf, size_t count);
 ssize_t write_blockwise(int fd, int bsize, void *buf, size_t count);
 ssize_t read_blockwise(int fd, int bsize, void *buf, size_t count);
 ssize_t write_lseek_blockwise(int fd, int bsize, char *buf, size_t count, off_t offset);
-ssize_t read_lseek_blockwise(int fd, int bsize, char *buf, size_t count, off_t offset);
+ssize_t read_lseek_blockwise(int fd, int bsize, void *buf, size_t count, off_t offset);
 
 unsigned crypt_getpagesize(void);
 int init_crypto(struct crypt_device *ctx);
diff --git a/lib/utils.c b/lib/utils.c
index d9843fa2..c677da94 100644
--- a/lib/utils.c
+++ b/lib/utils.c
@@ -276,7 +276,7 @@ out:
 	return ret;
 }
 
-ssize_t read_lseek_blockwise(int fd, int bsize, char *buf, size_t count, off_t offset)
+ssize_t read_lseek_blockwise(int fd, int bsize, void *buf, size_t count, off_t offset)
 {
 	char *frontPadBuf;
 	void *frontPadBuf_base = NULL;