From e40ba6d56b41754b37b995dbc8035b2b3a6afd8a Mon Sep 17 00:00:00 2001 From: Mimi Zohar Date: Thu, 19 Nov 2015 12:39:22 -0500 Subject: firmware: replace call to fw_read_file_contents() with kernel version Replace the fw_read_file_contents with kernel_file_read_from_path(). Although none of the upstreamed LSMs define a kernel_fw_from_file hook, IMA is called by the security function to prevent unsigned firmware from being loaded and to measure/appraise signed firmware, based on policy. Instead of reading the firmware twice, once for measuring/appraising the firmware and again for reading the firmware contents into memory, the kernel_post_read_file() security hook calculates the file hash based on the in memory file buffer. The firmware is read once. This patch removes the LSM kernel_fw_from_file() hook and security call. Changelog v4+: - revert dropped buf->size assignment - reported by Sergey Senozhatsky v3: - remove kernel_fw_from_file hook - use kernel_file_read_from_path() - requested by Luis v2: - reordered and squashed firmware patches - fix MAX firmware size (Kees Cook) Signed-off-by: Mimi Zohar Acked-by: Kees Cook Acked-by: Luis R. Rodriguez --- drivers/base/firmware_class.c | 52 +++++++++---------------------------------- 1 file changed, 10 insertions(+), 42 deletions(-) (limited to 'drivers/base') diff --git a/drivers/base/firmware_class.c b/drivers/base/firmware_class.c index c743a2f18c33..a414008ea64c 100644 --- a/drivers/base/firmware_class.c +++ b/drivers/base/firmware_class.c @@ -23,6 +23,7 @@ #include #include #include +#include #include #include #include @@ -291,37 +292,6 @@ static const char * const fw_path[] = { module_param_string(path, fw_path_para, sizeof(fw_path_para), 0644); MODULE_PARM_DESC(path, "customized firmware image search path with a higher priority than default path"); -static int fw_read_file_contents(struct file *file, struct firmware_buf *fw_buf) -{ - int size; - char *buf; - int rc; - - if (!S_ISREG(file_inode(file)->i_mode)) - return -EINVAL; - size = i_size_read(file_inode(file)); - if (size <= 0) - return -EINVAL; - buf = vmalloc(size); - if (!buf) - return -ENOMEM; - rc = kernel_read(file, 0, buf, size); - if (rc != size) { - if (rc > 0) - rc = -EIO; - goto fail; - } - rc = security_kernel_fw_from_file(file, buf, size); - if (rc) - goto fail; - fw_buf->data = buf; - fw_buf->size = size; - return 0; -fail: - vfree(buf); - return rc; -} - static void fw_finish_direct_load(struct device *device, struct firmware_buf *buf) { @@ -334,6 +304,7 @@ static void fw_finish_direct_load(struct device *device, static int fw_get_filesystem_firmware(struct device *device, struct firmware_buf *buf) { + loff_t size; int i, len; int rc = -ENOENT; char *path; @@ -343,8 +314,6 @@ static int fw_get_filesystem_firmware(struct device *device, return -ENOMEM; for (i = 0; i < ARRAY_SIZE(fw_path); i++) { - struct file *file; - /* skip the unset customized path */ if (!fw_path[i][0]) continue; @@ -356,18 +325,16 @@ static int fw_get_filesystem_firmware(struct device *device, break; } - file = filp_open(path, O_RDONLY, 0); - if (IS_ERR(file)) - continue; - rc = fw_read_file_contents(file, buf); - fput(file); + buf->size = 0; + rc = kernel_read_file_from_path(path, &buf->data, &size, + INT_MAX, READING_FIRMWARE); if (rc) { dev_warn(device, "loading %s failed with error %d\n", path, rc); continue; } - dev_dbg(device, "direct-loading %s\n", - buf->fw_id); + dev_dbg(device, "direct-loading %s\n", buf->fw_id); + buf->size = size; fw_finish_direct_load(device, buf); break; } @@ -689,8 +656,9 @@ static ssize_t firmware_loading_store(struct device *dev, dev_err(dev, "%s: map pages failed\n", __func__); else - rc = security_kernel_fw_from_file(NULL, - fw_buf->data, fw_buf->size); + rc = security_kernel_post_read_file(NULL, + fw_buf->data, fw_buf->size, + READING_FIRMWARE); /* * Same logic as fw_load_abort, only the DONE bit -- cgit v1.2.3-55-g7522