diff options
Diffstat (limited to 'security/security.c')
| -rw-r--r-- | security/security.c | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/security/security.c b/security/security.c index 67af9228c4e9..4e999f023651 100644 --- a/security/security.c +++ b/security/security.c @@ -61,6 +61,7 @@ const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX + 1] = { [LOCKDOWN_BPF_WRITE_USER] = "use of bpf to write user RAM", [LOCKDOWN_DBG_WRITE_KERNEL] = "use of kgdb/kdb to write kernel RAM", [LOCKDOWN_RTAS_ERROR_INJECTION] = "RTAS error injection", + [LOCKDOWN_XEN_USER_ACTIONS] = "Xen guest user action", [LOCKDOWN_INTEGRITY_MAX] = "integrity", [LOCKDOWN_KCORE] = "/proc/kcore access", [LOCKDOWN_KPROBES] = "use of kprobes", @@ -81,6 +82,7 @@ const struct lsm_id *lsm_idlist[MAX_LSM_COUNT]; struct lsm_blob_sizes blob_sizes; struct kmem_cache *lsm_file_cache; +struct kmem_cache *lsm_backing_file_cache; struct kmem_cache *lsm_inode_cache; #define SECURITY_HOOK_ACTIVE_KEY(HOOK, IDX) security_hook_active_##HOOK##_##IDX @@ -173,6 +175,30 @@ static int lsm_file_alloc(struct file *file) } /** + * lsm_backing_file_alloc - allocate a composite backing file blob + * @backing_file: the backing file + * + * Allocate the backing file blob for all the modules. + * + * Returns 0, or -ENOMEM if memory can't be allocated. + */ +static int lsm_backing_file_alloc(struct file *backing_file) +{ + void *blob; + + if (!lsm_backing_file_cache) { + backing_file_set_security(backing_file, NULL); + return 0; + } + + blob = kmem_cache_zalloc(lsm_backing_file_cache, GFP_KERNEL); + backing_file_set_security(backing_file, blob); + if (!blob) + return -ENOMEM; + return 0; +} + +/** * lsm_blob_alloc - allocate a composite blob * @dest: the destination for the blob * @size: the size of the blob @@ -2418,6 +2444,57 @@ void security_file_free(struct file *file) } /** + * security_backing_file_alloc() - Allocate and setup a backing file blob + * @backing_file: the backing file + * @user_file: the associated user visible file + * + * Allocate a backing file LSM blob and perform any necessary initialization of + * the LSM blob. There will be some operations where the LSM will not have + * access to @user_file after this point, so any important state associated + * with @user_file that is important to the LSM should be captured in the + * backing file's LSM blob. + * + * LSM's should avoid taking a reference to @user_file in this hook as it will + * result in problems later when the system attempts to drop/put the file + * references due to a circular dependency. + * + * Return: Return 0 if the hook is successful, negative values otherwise. + */ +int security_backing_file_alloc(struct file *backing_file, + const struct file *user_file) +{ + int rc; + + rc = lsm_backing_file_alloc(backing_file); + if (rc) + return rc; + rc = call_int_hook(backing_file_alloc, backing_file, user_file); + if (unlikely(rc)) + security_backing_file_free(backing_file); + + return rc; +} + +/** + * security_backing_file_free() - Free a backing file blob + * @backing_file: the backing file + * + * Free any LSM state associate with a backing file's LSM blob, including the + * blob itself. + */ +void security_backing_file_free(struct file *backing_file) +{ + void *blob = backing_file_security(backing_file); + + call_void_hook(backing_file_free, backing_file); + + if (blob) { + backing_file_set_security(backing_file, NULL); + kmem_cache_free(lsm_backing_file_cache, blob); + } +} + +/** * security_file_ioctl() - Check if an ioctl is allowed * @file: associated file * @cmd: ioctl cmd @@ -2506,6 +2583,32 @@ int security_mmap_file(struct file *file, unsigned long prot, } /** + * security_mmap_backing_file - Check if mmap'ing a backing file is allowed + * @vma: the vm_area_struct for the mmap'd region + * @backing_file: the backing file being mmap'd + * @user_file: the user file being mmap'd + * + * Check permissions for a mmap operation on a stacked filesystem. This hook + * is called after the security_mmap_file() and is responsible for authorizing + * the mmap on @backing_file. It is important to note that the mmap operation + * on @user_file has already been authorized and the @vma->vm_file has been + * set to @backing_file. + * + * Return: Returns 0 if permission is granted. + */ +int security_mmap_backing_file(struct vm_area_struct *vma, + struct file *backing_file, + struct file *user_file) +{ + /* recommended by the stackable filesystem devs */ + if (WARN_ON_ONCE(!(backing_file->f_mode & FMODE_BACKING))) + return -EIO; + + return call_int_hook(mmap_backing_file, vma, backing_file, user_file); +} +EXPORT_SYMBOL_GPL(security_mmap_backing_file); + +/** * security_mmap_addr() - Check if mmap'ing an address is allowed * @addr: address * @@ -4731,6 +4834,26 @@ int security_mptcp_add_subflow(struct sock *sk, struct sock *ssk) #endif /* CONFIG_SECURITY_NETWORK */ +#if defined(CONFIG_SECURITY_NETWORK) && defined(CONFIG_SECURITY_PATH) +/** + * security_unix_find() - Check if a named AF_UNIX socket can connect + * @path: path of the socket being connected to + * @other: peer sock + * @flags: flags associated with the socket + * + * This hook is called to check permissions before connecting to a named + * AF_UNIX socket. The caller does not hold any locks on @other. + * + * Return: Returns 0 if permission is granted. + */ +int security_unix_find(const struct path *path, struct sock *other, int flags) +{ + return call_int_hook(unix_find, path, other, flags); +} +EXPORT_SYMBOL(security_unix_find); + +#endif /* CONFIG_SECURITY_NETWORK && CONFIG_SECURITY_PATH */ + #ifdef CONFIG_SECURITY_INFINIBAND /** * security_ib_pkey_access() - Check if access to an IB pkey is allowed |