diff options
| author | Kees Cook <kees@ubuntu.com> | 2009-04-02 15:49:29 -0700 |
|---|---|---|
| committer | James Morris <jmorris@namei.org> | 2009-04-03 11:47:11 +1100 |
| commit | 3d43321b7015387cfebbe26436d0e9d299162ea1 (patch) | |
| tree | bae6bd123c8f573e844a7af11c96eb5f6a73e0ee /kernel/module.c | |
| parent | 8a6f83afd0c5355db6d11394a798e94950306239 (diff) | |
| download | lwn-3d43321b7015387cfebbe26436d0e9d299162ea1.tar.gz lwn-3d43321b7015387cfebbe26436d0e9d299162ea1.zip | |
modules: sysctl to block module loading
Implement a sysctl file that disables module-loading system-wide since
there is no longer a viable way to remove CAP_SYS_MODULE after the system
bounding capability set was removed in 2.6.25.
Value can only be set to "1", and is tested only if standard capability
checks allow CAP_SYS_MODULE. Given existing /dev/mem protections, this
should allow administrators a one-way method to block module loading
after initial boot-time module loading has finished.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'kernel/module.c')
| -rw-r--r-- | kernel/module.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/kernel/module.c b/kernel/module.c index f77ac320d0b5..eeb3f7b1383c 100644 --- a/kernel/module.c +++ b/kernel/module.c @@ -778,6 +778,9 @@ static void wait_for_zero_refcount(struct module *mod) mutex_lock(&module_mutex); } +/* Block module loading/unloading? */ +int modules_disabled = 0; + SYSCALL_DEFINE2(delete_module, const char __user *, name_user, unsigned int, flags) { @@ -785,7 +788,7 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user, char name[MODULE_NAME_LEN]; int ret, forced = 0; - if (!capable(CAP_SYS_MODULE)) + if (!capable(CAP_SYS_MODULE) || modules_disabled) return -EPERM; if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0) @@ -2349,7 +2352,7 @@ SYSCALL_DEFINE3(init_module, void __user *, umod, int ret = 0; /* Must have permission */ - if (!capable(CAP_SYS_MODULE)) + if (!capable(CAP_SYS_MODULE) || modules_disabled) return -EPERM; /* Only one module load at a time, please */ |