From 13752fe2d7f2d41c2fd92a5d1b1c6e38c4de0c05 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 25 Feb 2014 10:28:04 -0800 Subject: security: introduce kernel_fw_from_file hook In order to validate the contents of firmware being loaded, there must be a hook to evaluate any loaded firmware that wasn't built into the kernel itself. Without this, there is a risk that a root user could load malicious firmware designed to mount an attack against kernel memory (e.g. via DMA). Signed-off-by: Kees Cook Reviewed-by: Takashi Iwai --- include/linux/security.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'include') diff --git a/include/linux/security.h b/include/linux/security.h index 59820f8782a1..0ae4b147718a 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -702,6 +702,15 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts) * @inode points to the inode to use as a reference. * The current task must be the one that nominated @inode. * Return 0 if successful. + * @kernel_fw_from_file: + * Load firmware from userspace (not called for built-in firmware). + * @file contains the file structure pointing to the file containing + * the firmware to load. This argument will be NULL if the firmware + * was loaded via the uevent-triggered blob-based interface exposed + * by CONFIG_FW_LOADER_USER_HELPER. + * @buf pointer to buffer containing firmware contents. + * @size length of the firmware contents. + * Return 0 if permission is granted. * @kernel_module_request: * Ability to trigger the kernel to automatically upcall to userspace for * userspace to load a kernel module with the given name. @@ -1568,6 +1577,7 @@ struct security_operations { void (*cred_transfer)(struct cred *new, const struct cred *old); int (*kernel_act_as)(struct cred *new, u32 secid); int (*kernel_create_files_as)(struct cred *new, struct inode *inode); + int (*kernel_fw_from_file)(struct file *file, char *buf, size_t size); int (*kernel_module_request)(char *kmod_name); int (*kernel_module_from_file)(struct file *file); int (*task_fix_setuid) (struct cred *new, const struct cred *old, @@ -1840,6 +1850,7 @@ int security_prepare_creds(struct cred *new, const struct cred *old, gfp_t gfp); void security_transfer_creds(struct cred *new, const struct cred *old); int security_kernel_act_as(struct cred *new, u32 secid); int security_kernel_create_files_as(struct cred *new, struct inode *inode); +int security_kernel_fw_from_file(struct file *file, char *buf, size_t size); int security_kernel_module_request(char *kmod_name); int security_kernel_module_from_file(struct file *file); int security_task_fix_setuid(struct cred *new, const struct cred *old, @@ -2366,6 +2377,12 @@ static inline int security_kernel_create_files_as(struct cred *cred, return 0; } +static inline int security_kernel_fw_from_file(struct file *file, + char *buf, size_t size) +{ + return 0; +} + static inline int security_kernel_module_request(char *kmod_name) { return 0; -- cgit v1.2.3