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

[Richard Guy Briggs <rgb@redhat.com>]

On 2017-01-30 11:54, Steve Grubb wrote:
> On Thu, 26 Jan 2017 14:50:07 -0500
> Richard Guy Briggs <rgb@redhat.com> wrote:
> 
> > This adds a new auxiliary record MODULE_INIT to the SYSCALL event.
> 
> Thanks, this is definitely needed. Can you provide an example event
> generated by this?

It's in the wiki RFE, the second link provided.

> -Steve
> 
> > 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
> > 
> > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
> > ---
> >  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 476bc12..6222042 100644
> > --- a/include/linux/audit.h
> > +++ b/include/linux/audit.h
> > @@ -358,6 +358,7 @@ 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)
> >  {
> > @@ -434,6 +435,12 @@ 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);
> > +}
> > +
> >  extern int audit_n_rules;
> >  extern int audit_signals;
> >  #else /* CONFIG_AUDITSYSCALL */
> > @@ -539,6 +546,11 @@ 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 843540c..513c930 100644
> > --- a/include/uapi/linux/audit.h
> > +++ b/include/uapi/linux/audit.h
> > @@ -110,6 +110,7 @@
> >  #define AUDIT_SECCOMP		1326	/* Secure Computing
> > event */ #define AUDIT_PROCTITLE		1327	/*
> > Proctitle emit event */ #define AUDIT_FEATURE_CHANGE
> > 1328	/* audit log listing feature changes */ +#define
> > AUDIT_MODULE_INIT	1329	/* 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 de6cbb7..cf86486 100644
> > --- a/kernel/audit.h
> > +++ b/kernel/audit.h
> > @@ -198,6 +198,9 @@ 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 b86cc04..93967b8 100644
> > --- a/kernel/auditsc.c
> > +++ b/kernel/auditsc.c
> > @@ -1168,6 +1168,14 @@ static void audit_log_execve_info(struct
> > audit_context *context, kfree(buf);
> >  }
> >  
> > +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;
> > @@ -1264,6 +1272,9 @@ 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;
> >  	}
> >  	audit_log_end(ab);
> >  }
> > @@ -2356,6 +2367,15 @@ 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 8f051a1..214ba85 100644
> > --- a/kernel/module.c
> > +++ b/kernel/module.c
> > @@ -59,6 +59,7 @@
> >  #include <linux/jump_label.h>
> >  #include <linux/pfn.h>
> >  #include <linux/bsearch.h>
> > +#include <linux/audit.h>
> >  #include <uapi/linux/module.h>
> >  #include "module-internal.h"
> >  
> > @@ -3441,6 +3442,8 @@ 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)
> > @@ -3525,7 +3528,7 @@ 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 bug_cleanup;
> 

- RGB

--
Richard Guy Briggs <rgb@redhat.com>
Kernel Security Engineering, Base Operating Systems, Red Hat
Remote, Ottawa, Canada
Voice: +1.647.777.2635, Internal: (81) 32635