Re: [PATCH V2] audit: log module name on init_module

From: Richard Guy Briggs
Date: Tue Feb 14 2017 - 13:11:38 EST


On 2017-02-14 13:02, Steve Grubb wrote:
> On Monday, February 13, 2017 4:20:55 PM EST Paul Moore wrote:
> > On Sat, Feb 4, 2017 at 1:10 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-fo
> > > rmat
> > Correction for the record:
> >
> > *
> > https://github.com/linux-audit/audit-kernel/wiki/RFE-Module-Load-Record-For
> > mat
> >
> > [NOTE: don't resend please, I'll fix this when merging]
>
> OK. Support was added to user space for this record. While doing this, I
> wondered if we also get this auxiliary record when unloading a module?

I thought of that at the time, which influenced the design and wording.
It is not supported yet, but that should be easier to add.

> -Steve
>
> > > 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 | 14 ++++++++++++++
> > > kernel/module.c | 5 ++++-
> > > 5 files changed, 34 insertions(+), 1 deletions(-)
> >
> > This patch looks fine to me, and due to lack of comments I'm going to
> > assume that Jessica is okay with the kernel/module.c portions of this
> > patch. Normally this would be too close to the merge window, but this
> > patch is trivial and since it is new functionality it is unlikely to
> > cause any regressions so I'm going to merge it into audit/next now.
> >
> > > diff --git a/include/linux/audit.h b/include/linux/audit.h
> > > index 2be99b2..aba3a26 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_log_kern_module(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_log_kern_module(char *name)
> > > +{
> > > + if (!audit_dummy_context())
> > > + __audit_log_kern_module(name);
> > > +}
> > > +
> > >
> > > 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_log_kern_module(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..3c02bb2 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_KERN_MODULE 1330 /* Kernel Module events */
> > >
> > > #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..bde3aac 100644
> > > --- a/kernel/auditsc.c
> > > +++ b/kernel/auditsc.c
> > > @@ -1268,6 +1268,11 @@ static void show_special(struct audit_context
> > > *context, int *call_panic)>
> > > case AUDIT_EXECVE: {
> > >
> > > audit_log_execve_info(context, &ab);
> > > break; }
> > >
> > > + case AUDIT_KERN_MODULE:
> > > + audit_log_format(ab, "name=");
> > > + audit_log_untrustedstring(ab, context->module.name);
> > > + kfree(context->module.name);
> > > + break;
> > >
> > > }
> > > audit_log_end(ab);
> > >
> > > }
> > >
> > > @@ -2368,6 +2373,15 @@ void __audit_mmap_fd(int fd, int flags)
> > >
> > > context->type = AUDIT_MMAP;
> > >
> > > }
> > >
> > > +void __audit_log_kern_module(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_KERN_MODULE;
> > > +}
> > > +
> > >
> > > 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..5432dbe 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_log_kern_module(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;
> > >
> > > --
> > > 1.7.1
> > >
> > > --
> > > Linux-audit mailing list
> > > Linux-audit@xxxxxxxxxx
> > > https://www.redhat.com/mailman/listinfo/linux-audit
>
>

- 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