diff options
| author | Jeff Vander Stoep <jeffv@google.com> | 2016-04-05 13:06:27 -0700 |
|---|---|---|
| committer | Paul Moore <paul@paul-moore.com> | 2016-04-05 16:11:56 -0400 |
| commit | 61d612ea731e57dc510472fb746b55cdc017f371 (patch) | |
| tree | b44c2c0228284fffaa2f7a09de7bae85da0a3d72 | |
| parent | 0c6181cb301fd04a5800920ba423be753b0a4a01 (diff) | |
selinux: restrict kernel module loading
Utilize existing kernel_read_file hook on kernel module load.
Add module_load permission to the system class.
Enforces restrictions on kernel module origin when calling the
finit_module syscall. The hook checks that source type has
permission module_load for the target type.
Example for finit_module:
allow foo bar_file:system module_load;
Similarly restrictions are enforced on kernel module loading when
calling the init_module syscall. The hook checks that source
type has permission module_load with itself as the target object
because the kernel module is sourced from the calling process.
Example for init_module:
allow foo foo:system module_load;
Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
[PM: fixed return value of selinux_kernel_read_file()]
Signed-off-by: Paul Moore <paul@paul-moore.com>
| -rw-r--r-- | security/selinux/hooks.c | 47 | ||||
| -rw-r--r-- | security/selinux/include/classmap.h | 2 |
2 files changed, 48 insertions, 1 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 5003b5aa3b43..fce7dc81f2d9 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -3722,6 +3722,52 @@ static int selinux_kernel_module_request(char *kmod_name) SYSTEM__MODULE_REQUEST, &ad); } +static int selinux_kernel_module_from_file(struct file *file) +{ + struct common_audit_data ad; + struct inode_security_struct *isec; + struct file_security_struct *fsec; + u32 sid = current_sid(); + int rc; + + /* init_module */ + if (file == NULL) + return avc_has_perm(sid, sid, SECCLASS_SYSTEM, + SYSTEM__MODULE_LOAD, NULL); + + /* finit_module */ + ad.type = LSM_AUDIT_DATA_PATH; + ad.u.path = file->f_path; + + isec = inode_security(file_inode(file)); + fsec = file->f_security; + + if (sid != fsec->sid) { + rc = avc_has_perm(sid, fsec->sid, SECCLASS_FD, FD__USE, &ad); + if (rc) + return rc; + } + + return avc_has_perm(sid, isec->sid, SECCLASS_SYSTEM, + SYSTEM__MODULE_LOAD, &ad); +} + +static int selinux_kernel_read_file(struct file *file, + enum kernel_read_file_id id) +{ + int rc = 0; + + switch (id) { + case READING_MODULE: + rc = selinux_kernel_module_from_file(file); + break; + default: + break; + } + + return rc; +} + static int selinux_task_setpgid(struct task_struct *p, pid_t pgid) { return current_has_perm(p, PROCESS__SETPGID); @@ -6018,6 +6064,7 @@ static struct security_hook_list selinux_hooks[] = { LSM_HOOK_INIT(kernel_act_as, selinux_kernel_act_as), LSM_HOOK_INIT(kernel_create_files_as, selinux_kernel_create_files_as), LSM_HOOK_INIT(kernel_module_request, selinux_kernel_module_request), + LSM_HOOK_INIT(kernel_read_file, selinux_kernel_read_file), LSM_HOOK_INIT(task_setpgid, selinux_task_setpgid), LSM_HOOK_INIT(task_getpgid, selinux_task_getpgid), LSM_HOOK_INIT(task_getsid, selinux_task_getsid), diff --git a/security/selinux/include/classmap.h b/security/selinux/include/classmap.h index ef83c4b85a33..8fbd1383d75e 100644 --- a/security/selinux/include/classmap.h +++ b/security/selinux/include/classmap.h @@ -32,7 +32,7 @@ struct security_class_mapping secclass_map[] = { "setsockcreate", NULL } }, { "system", { "ipc_info", "syslog_read", "syslog_mod", - "syslog_console", "module_request", NULL } }, + "syslog_console", "module_request", "module_load", NULL } }, { "capability", { "chown", "dac_override", "dac_read_search", "fowner", "fsetid", "kill", "setgid", "setuid", "setpcap", |