Re: [RFC] [PATCH] audit: log module name on init_module
From: Richard Guy Briggs
Date: Tue Jan 31 2017 - 07:36:38 EST
On 2017-01-31 06:59, Paul Moore wrote:
> On Thu, Jan 26, 2017 at 4:21 PM, Richard Guy Briggs <rgb@xxxxxxxxxx> wrote:
> > This adds a new auxiliary record MODULE_INIT to the SYSCALL event.
> >
> > We get finit_module for free since it made most sense to hook this in to
> > load_module().
> >
> > https://github.com/linux-audit/audit-kernel/issues/7
> > https://github.com/linux-audit/audit-kernel/wiki/RFE-Module-load-record-format
>
> Consistency nit: capitalize the first letter in the wiki page words
> (see the existing RFE pages)
>
> > Signed-off-by: Richard Guy Briggs <rgb@xxxxxxxxxx>
> > ---
> > include/linux/audit.h | 12 ++++++++++++
> > include/uapi/linux/audit.h | 1 +
> > kernel/audit.h | 3 +++
> > kernel/auditsc.c | 20 ++++++++++++++++++++
> > kernel/module.c | 5 ++++-
> > 5 files changed, 40 insertions(+), 1 deletions(-)
> >
> > diff --git a/include/linux/audit.h b/include/linux/audit.h
> > index 2be99b2..7bb23d5 100644
> > --- a/include/linux/audit.h
> > +++ b/include/linux/audit.h
> > @@ -360,6 +360,7 @@ extern int __audit_log_bprm_fcaps(struct linux_binprm *bprm,
> > const struct cred *old);
> > extern void __audit_log_capset(const struct cred *new, const struct cred *old);
> > extern void __audit_mmap_fd(int fd, int flags);
> > +extern void __audit_module_init(char *name);
> >
> > static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp)
> > {
> > @@ -450,6 +451,12 @@ static inline void audit_mmap_fd(int fd, int flags)
> > __audit_mmap_fd(fd, flags);
> > }
> >
> > +static inline void audit_module_init(char *name)
> > +{
> > + if (!audit_dummy_context())
> > + __audit_module_init(name);
> > +}
>
> More on this below, but I was expecting the function above to named
> audit_log_kern_module(), or something similar.
Ok fair enough, I had mis-understood your previous point.
Any comment on the new record format?
> > extern int audit_n_rules;
> > extern int audit_signals;
> > #else /* CONFIG_AUDITSYSCALL */
> > @@ -561,6 +568,11 @@ static inline void audit_log_capset(const struct cred *new,
> > { }
> > static inline void audit_mmap_fd(int fd, int flags)
> > { }
> > +
> > +static inline void audit_module_init(char *name)
> > +{
> > +}
> > +
> > static inline void audit_ptrace(struct task_struct *t)
> > { }
> > #define audit_n_rules 0
> > diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
> > index 3f24110..4a328b4 100644
> > --- a/include/uapi/linux/audit.h
> > +++ b/include/uapi/linux/audit.h
> > @@ -111,6 +111,7 @@
> > #define AUDIT_PROCTITLE 1327 /* Proctitle emit event */
> > #define AUDIT_FEATURE_CHANGE 1328 /* audit log listing feature changes */
> > #define AUDIT_REPLACE 1329 /* Replace auditd if this packet unanswerd */
> > +#define AUDIT_MODULE_INIT 1330 /* Module init event */
> >
> > #define AUDIT_AVC 1400 /* SE Linux avc denial or grant */
> > #define AUDIT_SELINUX_ERR 1401 /* Internal SE Linux Errors */
> > diff --git a/kernel/audit.h b/kernel/audit.h
> > index 431444c..144b7eb 100644
> > --- a/kernel/audit.h
> > +++ b/kernel/audit.h
> > @@ -199,6 +199,9 @@ struct audit_context {
> > struct {
> > int argc;
> > } execve;
> > + struct {
> > + char *name;
> > + } module;
> > };
> > int fds[2];
> > struct audit_proctitle proctitle;
> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> > index bb5f504..3e12678 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -1172,6 +1172,14 @@ out:
> > kfree(buf_head);
> > }
> >
> > +static void audit_log_kern_module(struct audit_context *context,
> > + struct audit_buffer **ab)
> > +{
> > + audit_log_format(*ab, " name=");
> > + audit_log_untrustedstring(*ab, context->module.name);
> > + kfree(context->module.name);
> > +}
> > +
> > static void show_special(struct audit_context *context, int *call_panic)
> > {
> > struct audit_buffer *ab;
> > @@ -1268,6 +1276,9 @@ static void show_special(struct audit_context *context, int *call_panic)
> > case AUDIT_EXECVE: {
> > audit_log_execve_info(context, &ab);
> > break; }
> > + case AUDIT_MODULE_INIT:
> > + audit_log_kern_module(context, &ab);
> > + break;
>
> With the exception of AUDIT_EXECVE everything else in show_special()
> is simply open coded inside the show_special() function; considering
> that audit_log_kern_module() is trivial it seems like a separate
> function isn't really needed here.
>
> > }
> > audit_log_end(ab);
> > }
> > @@ -2368,6 +2379,15 @@ void __audit_mmap_fd(int fd, int flags)
> > context->type = AUDIT_MMAP;
> > }
> >
> > +void __audit_module_init(char *name)
> > +{
> > + struct audit_context *context = current->audit_context;
> > +
> > + context->module.name = kmalloc(strlen(name) + 1, GFP_KERNEL);
> > + strcpy(context->module.name, name);
> > + context->type = AUDIT_MODULE_INIT;
> > +}
> > +
> > static void audit_log_task(struct audit_buffer *ab)
> > {
> > kuid_t auid, uid;
> > diff --git a/kernel/module.c b/kernel/module.c
> > index 529efae..678407e 100644
> > --- a/kernel/module.c
> > +++ b/kernel/module.c
> > @@ -61,6 +61,7 @@
> > #include <linux/pfn.h>
> > #include <linux/bsearch.h>
> > #include <linux/dynamic_debug.h>
> > +#include <linux/audit.h>
> > #include <uapi/linux/module.h>
> > #include "module-internal.h"
> >
> > @@ -3593,6 +3594,8 @@ static int load_module(struct load_info *info, const char __user *uargs,
> > goto free_copy;
> > }
> >
> > + audit_module_init(mod->name);
> > +
> > /* Reserve our place in the list. */
> > err = add_unformed_module(mod);
> > if (err)
> > @@ -3681,7 +3684,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
> > mod->name, after_dashes);
> > }
> >
> > - /* Link in to syfs. */
> > + /* Link in to sysfs. */
> > err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp);
> > if (err < 0)
> > goto coming_cleanup;
>
> paul moore
- RGB
--
Richard Guy Briggs <rgb@xxxxxxxxxx>
Kernel Security Engineering, Base Operating Systems, Red Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635