As pointed out, feof() will always fail after a rewind

src/userauth.c

@@ -254,11 +254,11 @@ static int libssh2_file_read_publickey(LIBSSH2_SESSION *session, unsigned char *
 		return -1;
 	}
 	while (!feof(fd) && (c = fgetc(fd)) != '\r' && c != '\n')	pubkey_len++;
-	rewind(fd);
 	if (feof(fd)) {
 		/* the last character was EOF */
 		pubkey_len--;
 	}
+	rewind(fd);
 	
 	if (pubkey_len <= 1) {
 		libssh2_error(session, LIBSSH2_ERROR_FILE, "Invalid data in public key file", 0);