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Re: [PATCH] audit: audit on the future execution of a binary.



Hey Eric,

did you have any comments on this? Is there a better way to do this?

Cheers,
peter

On Thu, Aug 23, 2012 at 12:24 PM, Peter Moody <pmoody google com> wrote:
> This adds the ability audit the actions of a not-yet-running process,
> as well as the children of a not-yet-running process.
>
> Signed-off-by: Peter Moody <pmoody google com>
> ---
>  include/linux/audit.h |    2 ++
>  kernel/auditfilter.c  |    6 ++++++
>  kernel/auditsc.c      |   47 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 55 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/audit.h b/include/linux/audit.h
> index 22f292a..5506cb1 100644
> --- a/include/linux/audit.h
> +++ b/include/linux/audit.h
> @@ -260,6 +260,8 @@
>  #define AUDIT_OBJ_UID  109
>  #define AUDIT_OBJ_GID  110
>  #define AUDIT_FIELD_COMPARE    111
> +#define AUDIT_EXE      112
> +#define AUDIT_EXE_CHILDREN     113
>
>  #define AUDIT_ARG0      200
>  #define AUDIT_ARG1      (AUDIT_ARG0+1)
> diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
> index a6c3f1a..1e6c571 100644
> --- a/kernel/auditfilter.c
> +++ b/kernel/auditfilter.c
> @@ -546,6 +546,12 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data,
>                         if (f->val > AUDIT_MAX_FIELD_COMPARE)
>                                 goto exit_free;
>                         break;
> +               case AUDIT_EXE:
> +               case AUDIT_EXE_CHILDREN:
> +                       if (f->op != Audit_equal) {
> +                               goto exit_free;
> +                       }
> +                       break;
>                 default:
>                         goto exit_free;
>                 }
> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
> index 4b96415..9cebe95 100644
> --- a/kernel/auditsc.c
> +++ b/kernel/auditsc.c
> @@ -46,6 +46,7 @@
>  #include <asm/types.h>
>  #include <linux/atomic.h>
>  #include <linux/fs.h>
> +#include <linux/dcache.h>
>  #include <linux/namei.h>
>  #include <linux/mm.h>
>  #include <linux/export.h>
> @@ -68,6 +69,7 @@
>  #include <linux/capability.h>
>  #include <linux/fs_struct.h>
>  #include <linux/compat.h>
> +#include <linux/sched.h>
>
>  #include "audit.h"
>
> @@ -592,6 +594,35 @@ static int audit_field_compare(struct task_struct *tsk,
>         return 0;
>  }
>
> +int audit_match_exe(struct task_struct *tsk, struct audit_field *f)
> +{
> +       int result = 0;
> +       struct mm_struct *mm;
> +       struct vm_area_struct *vma;
> +
> +       if (!tsk)
> +               goto out;
> +
> +       mm = tsk->mm;
> +       if (!mm)
> +               goto out;
> +
> +       down_read(&mm->mmap_sem);
> +       vma = mm->mmap;
> +       while (vma) {
> +               if ((vma->vm_flags & VM_EXECUTABLE) &&
> +                   vma->vm_file) {
> +                       struct inode *ino = vma->vm_file->f_path.dentry->d_inode;
> +                       result = audit_comparator(ino->i_ino, f->op, f->val);
> +                       break;
> +               }
> +               vma = vma->vm_next;
> +       }
> +       up_read(&mm->mmap_sem);
> +out:
> +       return result;
> +}
> +
>  /* Determine if any context name data matches a rule's watch data */
>  /* Compare a task_struct with an audit_rule.  Return 1 on match, 0
>   * otherwise.
> @@ -629,6 +660,22 @@ static int audit_filter_rules(struct task_struct *tsk,
>                                 result = audit_comparator(ctx->ppid, f->op, f->val);
>                         }
>                         break;
> +               case AUDIT_EXE:
> +                       result = audit_match_exe(tsk, f);
> +                       break;
> +               case AUDIT_EXE_CHILDREN:
> +               {
> +                       struct task_struct *ptsk;
> +                       for (ptsk = tsk;
> +                            ptsk->parent->pid > 0;
> +                            ptsk = find_task_by_vpid(ptsk->parent->pid)) {
> +                               if (audit_match_exe(ptsk, f)) {
> +                                       ++result;
> +                                       break;
> +                               }
> +                       }
> +               }
> +                       break;
>                 case AUDIT_UID:
>                         result = audit_comparator(cred->uid, f->op, f->val);
>                         break;
> --
> 1.7.7.3
>



-- 
Peter Moody      Google    1.650.253.7306
Security Engineer  pgp:0xC3410038


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