Re: [PATCH] audit: allow not equal op for audit by executable

On 2018-04-06 10:32, Steve Grubb wrote: > On Friday, April 6, 2018 4:43:00 AM EDT Ondrej Mosnacek wrote: > > Current implementation of auditing by executable name only implements > > the 'equal' operator. This patch extends it to also support the 'not > > equal' operator. > > > > See: https://github.com/linux-audit/audit-kernel/issues/53 > > What would an audit rule that uses this new capability look like? auditctl -a exit,always ... -F exe!=/path/to/exec

> > Signed-off-by: Ondrej Mosnacek <omosnace(a)redhat.com&gt; > > --- > > > > Hi Paul, > > > > this turned out to be easier than I anticipated so I'm sending the > > patch > > already :) I hope I got everything right. Note that the userspace tools > > also need to be updated to check the feature bit and allow/disallow the > > operator based on that. > > > > Ondrej > > > > include/uapi/linux/audit.h | 18 ++++++++++-------- > > kernel/auditfilter.c | 2 +- > > kernel/auditsc.c | 2 ++ > > 3 files changed, 13 insertions(+), 9 deletions(-) > > > > diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h > > index 4e61a9e05132..03393f7e8932 100644 > > --- a/include/uapi/linux/audit.h > > +++ b/include/uapi/linux/audit.h > > @@ -333,13 +333,14 @@ enum { > > > > #define AUDIT_STATUS_BACKLOG_WAIT_TIME 0x0020 > > #define AUDIT_STATUS_LOST 0x0040 > > > > -#define AUDIT_FEATURE_BITMAP_BACKLOG_LIMIT 0x00000001 > > -#define AUDIT_FEATURE_BITMAP_BACKLOG_WAIT_TIME 0x00000002 > > -#define AUDIT_FEATURE_BITMAP_EXECUTABLE_PATH 0x00000004 > > -#define AUDIT_FEATURE_BITMAP_EXCLUDE_EXTEND 0x00000008 > > -#define AUDIT_FEATURE_BITMAP_SESSIONID_FILTER 0x00000010 > > -#define AUDIT_FEATURE_BITMAP_LOST_RESET 0x00000020 > > -#define AUDIT_FEATURE_BITMAP_FILTER_FS 0x00000040 > > +#define AUDIT_FEATURE_BITMAP_BACKLOG_LIMIT 0x00000001 > > +#define AUDIT_FEATURE_BITMAP_BACKLOG_WAIT_TIME 0x00000002 > > +#define AUDIT_FEATURE_BITMAP_EXECUTABLE_PATH 0x00000004 > > +#define AUDIT_FEATURE_BITMAP_EXCLUDE_EXTEND 0x00000008 > > +#define AUDIT_FEATURE_BITMAP_SESSIONID_FILTER 0x00000010 > > +#define AUDIT_FEATURE_BITMAP_LOST_RESET 0x00000020 > > +#define AUDIT_FEATURE_BITMAP_FILTER_FS 0x00000040 > > +#define AUDIT_FEATURE_BITMAP_EXECUTABLE_PATH_NEQ 0x00000080 > > > > #define AUDIT_FEATURE_BITMAP_ALL (AUDIT_FEATURE_BITMAP_BACKLOG_LIMIT | > > \ > > > > AUDIT_FEATURE_BITMAP_BACKLOG_WAIT_TIME | \ > > > > @@ -347,7 +348,8 @@ enum { > > > > AUDIT_FEATURE_BITMAP_EXCLUDE_EXTEND | \ > > AUDIT_FEATURE_BITMAP_SESSIONID_FILTER | \ > > AUDIT_FEATURE_BITMAP_LOST_RESET | \ > > > > - AUDIT_FEATURE_BITMAP_FILTER_FS) > > + AUDIT_FEATURE_BITMAP_FILTER_FS | \ > > + AUDIT_FEATURE_BITMAP_EXECUTABLE_PATH_NEQ) > > > > /* deprecated: AUDIT_VERSION_* */ > > #define AUDIT_VERSION_LATEST AUDIT_FEATURE_BITMAP_ALL > > > > diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c > > index d7a807e81451..a0c5a3ec6e60 100644 > > --- a/kernel/auditfilter.c > > +++ b/kernel/auditfilter.c > > @@ -426,7 +426,7 @@ static int audit_field_valid(struct audit_entry > > *entry, struct audit_field *f) return -EINVAL; > > > > break; > > > > case AUDIT_EXE: > > - if (f->op != Audit_equal) > > + if (f->op != Audit_not_equal && f->op != Audit_equal) > > > > return -EINVAL; > > > > if (entry->rule.listnr != AUDIT_FILTER_EXIT) > > > > return -EINVAL; > > > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > > index 4e0a4ac803db..479c031ec54c 100644 > > --- a/kernel/auditsc.c > > +++ b/kernel/auditsc.c > > @@ -471,6 +471,8 @@ static int audit_filter_rules(struct task_struct > > *tsk, > > > > break; > > > > case AUDIT_EXE: > > result = audit_exe_compare(tsk, rule->exe); > > > > + if (f->op == Audit_not_equal) > > + result = !result; > > > > break; > > > > case AUDIT_UID: > > result = audit_uid_comparator(cred->uid, f->op, f->uid); - RGB -- Richard Guy Briggs <rgb(a)redhat.com&gt; Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635