From fe53d2a810abe0e1ee7cc0bb20fd520dc6605ecb Mon Sep 17 00:00:00 2001 From: Bjorn Andersson Date: Sat, 26 Oct 2019 11:14:03 -0700 Subject: [PATCH] tqftpserv: Implement path translation The tftp clients in the modem requests files from either /readwrite or /readonly/firmware/image, but as the wlanmdsp.mbn file requested is signed with a vendor specific key these paths needs to be translated. /readwrite is translated to /tmp/tqftpserv for now and the /readonly/firmware/image is translated to a search for the requested file alongside any of the remoteproc firmware files. The result is that the wlanmdsp.mbn can be stored in linux-firmware alongside it's device/vendor specific modem firmware. Signed-off-by: Bjorn Andersson --- Makefile | 2 +- tqftpserv.c | 15 ++--- translate.c | 182 ++++++++++++++++++++++++++++++++++++++++++++++++++++ translate.h | 6 ++ 4 files changed, 194 insertions(+), 11 deletions(-) create mode 100644 translate.c create mode 100644 translate.h diff --git a/Makefile b/Makefile index 89ab0b7..60ad687 100644 --- a/Makefile +++ b/Makefile @@ -7,7 +7,7 @@ prefix ?= /usr/local bindir := $(prefix)/bin servicedir := $(prefix)/lib/systemd/system -SRCS := tqftpserv.c +SRCS := tqftpserv.c translate.c OBJS := $(SRCS:.c=.o) diff --git a/tqftpserv.c b/tqftpserv.c index 5b63953..55b667f 100644 --- a/tqftpserv.c +++ b/tqftpserv.c @@ -40,8 +40,7 @@ #include #include "list.h" - -#define BASE_DIR "/" +#include "translate.h" #define MAX(x, y) ((x) > (y) ? (x) : (y)) @@ -212,7 +211,6 @@ static void handle_rrq(const char *buf, size_t len, struct sockaddr_qrtr *sq) size_t rsize = 0; size_t wsize = 0; bool do_oack = false; - char path[256]; int sock; int ret; int fd; @@ -275,10 +273,9 @@ static void handle_rrq(const char *buf, size_t len, struct sockaddr_qrtr *sq) return; } - snprintf(path, sizeof(path), BASE_DIR "/%s", filename); - fd = open(path, O_RDONLY); + fd = translate_open(filename, O_RDONLY); if (fd < 0) { - printf("[TQFTP] unable to open %s (%d), reject\n", path, errno); + printf("[TQFTP] unable to open %s (%d), reject\n", filename, errno); tftp_send_error(sock, 1, "file not found"); return; } @@ -317,7 +314,6 @@ static void handle_wrq(const char *buf, size_t len, struct sockaddr_qrtr *sq) struct tftp_client *client; const char *filename; const char *mode; - char path[256]; int sock; int ret; int fd; @@ -333,11 +329,10 @@ static void handle_wrq(const char *buf, size_t len, struct sockaddr_qrtr *sq) printf("[TQFTP] WRQ: %s (%s)\n", filename, mode); - snprintf(path, sizeof(path), BASE_DIR "/%s", filename); - fd = open(path, O_WRONLY | O_CREAT, 0666); + fd = translate_open(filename, O_WRONLY | O_CREAT); if (fd < 0) { /* XXX: error */ - printf("[TQFTP] unable to open %s (%d), reject\n", path, errno); + printf("[TQFTP] unable to open %s (%d), reject\n", filename, errno); return; } diff --git a/translate.c b/translate.c new file mode 100644 index 0000000..34c419e --- /dev/null +++ b/translate.c @@ -0,0 +1,182 @@ +/* + * Copyright (c) 2019, Linaro Ltd. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * 1. Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * + * 2. Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * 3. Neither the name of the copyright holder nor the names of its contributors + * may be used to endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "translate.h" + +#define READONLY_PATH "/readonly/firmware/image/" +#define READWRITE_PATH "/readwrite/" + +#define FIRMWARE_BASE "/lib/firmware/" + +/** + * translate_readonly() - open "file" residing with remoteproc firmware + * @file: file requested, stripped of "/readonly/image/" prefix + * + * It is assumed that the readonly files requested by the client resides under + * /lib/firmware in the same place as its associated remoteproc firmware. This + * function scans through all entries under /sys/class/remoteproc and read the + * dirname of each "firmware" file in an attempt to find, and open(2), the + * requested file. + * + * As these files are readonly, it's not possible to pass flags to open(2). + * + * Return: opened fd on success, -1 otherwise + */ +static int translate_readonly(const char *file) +{ + char firmware_value[PATH_MAX]; + char firmware_attr[32]; + char path[PATH_MAX]; + struct dirent *de; + int firmware_fd; + DIR *class_dir; + int class_fd; + ssize_t n; + int fd = -1; + + class_fd = open("/sys/class/remoteproc", O_RDONLY | O_DIRECTORY); + if (class_fd < 0) { + warn("failed to open remoteproc class"); + return -1; + } + + class_dir = fdopendir(class_fd); + if (!class_dir) { + warn("failed to opendir"); + goto close_class; + } + + while ((de = readdir(class_dir)) != NULL) { + if (!strcmp(de->d_name, ".") || !strcmp(de->d_name, "..")) + continue; + + if (strlen(de->d_name) + sizeof("/firmware") > sizeof(firmware_attr)) + continue; + strcpy(firmware_attr, de->d_name); + strcat(firmware_attr, "/firmware"); + + firmware_fd = openat(class_fd, firmware_attr, O_RDONLY); + if (firmware_fd < 0) + continue; + + n = read(firmware_fd, firmware_value, sizeof(firmware_value)); + close(firmware_fd); + if (n < 0) { + continue; + } + + if (strlen(FIRMWARE_BASE) + strlen(firmware_value) + 1 + + strlen(file) + 1 > sizeof(path)) + continue; + + strcpy(path, FIRMWARE_BASE); + strcat(path, dirname(firmware_value)); + strcat(path, "/"); + strcat(path, file); + + fd = open(path, O_RDONLY); + if (fd >= 0) + break; + + if (errno != ENOENT) + warn("failed to open %s", path); + } + + closedir(class_dir); + +close_class: + close(class_fd); + + return fd; +} + +/** + * translate_readwrite() - open "file" from a temporary directory + * @file: relative path of the requested file, with /readwrite/ stripped + * @flags: flags to be passed to open(2) + * + * Return: opened fd on success, -1 otherwise + */ +static int translate_readwrite(const char *file, int flags) +{ + int base; + int ret; + int fd; + + ret = mkdir("/tmp/tqftpserv", 0700); + if (ret < 0 && errno != EEXIST) { + warn("failed to create /tmp/tqftpserv"); + return -1; + } + + base = open("/tmp/tqftpserv", O_RDONLY | O_DIRECTORY); + if (base < 0) { + warn("failed top open /tmp/tqftpserv"); + return -1; + } + + fd = openat(base, file, flags, 0600); + close(base); + if (fd < 0) + warn("failed to open %s", file); + + return fd; +} + +/** + * translate_open() - open file after translating path + * + + * Strips /readonly/firmware/image and search among remoteproc firmware. + * Replaces /readwrite with a temporary directory. + + */ +int translate_open(const char *path, int flags) +{ + if (!strncmp(path, READONLY_PATH, strlen(READONLY_PATH))) + return translate_readonly(path + strlen(READONLY_PATH)); + else if (!strncmp(path, READWRITE_PATH, strlen(READWRITE_PATH))) + return translate_readwrite(path + strlen(READWRITE_PATH), flags); + + fprintf(stderr, "invalid path %s, rejecting\n", path); + errno = ENOENT; + return -1; +} diff --git a/translate.h b/translate.h new file mode 100644 index 0000000..ade2d09 --- /dev/null +++ b/translate.h @@ -0,0 +1,6 @@ +#ifndef __TRANSLATE_H__ +#define __TRANSLATE_H__ + +int translate_open(const char *path, int flags); + +#endif