Re: [PATCH ghak90 V5 08/10] audit: add containerid filtering

On 2019-03-18 21:02, Ondrej Mosnacek wrote: > On Fri, Mar 15, 2019 at 7:35 PM Richard Guy Briggs <rgb(a)redhat.com&gt; wrote: > > > > Implement audit container identifier filtering using the AUDIT_CONTID > > field name to send an 8-character string representing a u64 since the > > value field is only u32. > > > > Sending it as two u32 was considered, but gathering and comparing two > > fields was more complex. > > > > The feature indicator is AUDIT_FEATURE_BITMAP_CONTAINERID. > > > > See: https://github.com/linux-audit/audit-kernel/issues/91 > > See: https://github.com/linux-audit/audit-userspace/issues/40 > > See: https://github.com/linux-audit/audit-testsuite/issues/64 > > See: https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID > > Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com&gt; > > Acked-by: Serge Hallyn <serge(a)hallyn.com&gt; > > --- > > include/linux/audit.h | 1 + > > include/uapi/linux/audit.h | 5 ++++- > > kernel/audit.h | 1 + > > kernel/auditfilter.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++ > > kernel/auditsc.c | 3 +++ > > 5 files changed, 56 insertions(+), 1 deletion(-) > > > > diff --git a/include/linux/audit.h b/include/linux/audit.h > > index 6db5aba7cc01..fa19fa408931 100644 > > --- a/include/linux/audit.h > > +++ b/include/linux/audit.h > > @@ -77,6 +77,7 @@ struct audit_field { > > u32 type; > > union { > > u32 val; > > + u64 val64; > > kuid_t uid; > > kgid_t gid; > > struct { > > diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h > > index a6383e28b2c8..741ab6f38294 100644 > > --- a/include/uapi/linux/audit.h > > +++ b/include/uapi/linux/audit.h > > @@ -265,6 +265,7 @@ > > #define AUDIT_LOGINUID_SET 24 > > #define AUDIT_SESSIONID 25 /* Session ID */ > > #define AUDIT_FSTYPE 26 /* FileSystem Type */ > > +#define AUDIT_CONTID 27 /* Container ID */ > > > > /* These are ONLY useful when checking > > * at syscall exit time (AUDIT_AT_EXIT). */ > > @@ -345,6 +346,7 @@ enum { > > #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_CONTAINERID 0x00000080 > > > > #define AUDIT_FEATURE_BITMAP_ALL (AUDIT_FEATURE_BITMAP_BACKLOG_LIMIT | \ > > AUDIT_FEATURE_BITMAP_BACKLOG_WAIT_TIME | \ > > @@ -352,7 +354,8 @@ 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_CONTAINERID) > > > > /* deprecated: AUDIT_VERSION_* */ > > #define AUDIT_VERSION_LATEST AUDIT_FEATURE_BITMAP_ALL > > diff --git a/kernel/audit.h b/kernel/audit.h > > index 2a1a8b8a8019..3a40b608bf8d 100644 > > --- a/kernel/audit.h > > +++ b/kernel/audit.h > > @@ -230,6 +230,7 @@ static inline int audit_hash_ino(u32 ino) > > > > extern int audit_match_class(int class, unsigned syscall); > > extern int audit_comparator(const u32 left, const u32 op, const u32 right); > > +extern int audit_comparator64(const u64 left, const u32 op, const u64 right); > > extern int audit_uid_comparator(kuid_t left, u32 op, kuid_t right); > > extern int audit_gid_comparator(kgid_t left, u32 op, kgid_t right); > > extern int parent_len(const char *path); > > diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c > > index add360b46b38..516b8e58959e 100644 > > --- a/kernel/auditfilter.c > > +++ b/kernel/auditfilter.c > > @@ -410,6 +410,7 @@ static int audit_field_valid(struct audit_entry *entry, struct audit_field *f) > > /* FALL THROUGH */ > > case AUDIT_ARCH: > > case AUDIT_FSTYPE: > > + case AUDIT_CONTID: > > if (f->op != Audit_not_equal && f->op != Audit_equal) > > return -EINVAL; > > break; > > @@ -582,6 +583,14 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, > > } > > entry->rule.exe = audit_mark; > > break; > > + case AUDIT_CONTID: > > + if (f->val != sizeof(u64)) > > + goto exit_free; > > + str = audit_unpack_string(&bufp, &remain, f->val); > > + if (IS_ERR(str)) > > + goto exit_free; > > + f->val64 = ((u64 *)str)[0]; > > + break; > > } > > } > > > > @@ -664,6 +673,11 @@ static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule) > > data->buflen += data->values[i] = > > audit_pack_string(&bufp, audit_mark_path(krule->exe)); > > break; > > + case AUDIT_CONTID: > > + data->buflen += data->values[i] = sizeof(u64); > > + for (i = 0; i < sizeof(u64); i++) > > + ((char *)bufp)[i] = ((char *)&f->val64)[i]; > > How about just: > > memcpy(bufp, &f->val64, sizeof(u64)); > > instead of the awkward for loop? It is simpler and also more in line > with the code in audit_pack_string(). I'll grant you that. I'll use that instead.

> Also, doesn't this loop interfere with the outer loop that also uses > 'i' as the control variable? Yes, it does. Thank you for catching that. Doing a auditctl -l reveals this. > > + break; > > case AUDIT_LOGINUID_SET: > > if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) { > > data->fields[i] = AUDIT_LOGINUID; > > @@ -750,6 +764,10 @@ static int audit_compare_rule(struct audit_krule *a, struct audit_krule *b) > > if (!gid_eq(a->fields[i].gid, b->fields[i].gid)) > > return 1; > > break; > > + case AUDIT_CONTID: > > + if (a->fields[i].val64 != b->fields[i].val64) > > + return 1; > > + break; > > default: > > if (a->fields[i].val != b->fields[i].val) > > return 1; > > @@ -1206,6 +1224,31 @@ int audit_comparator(u32 left, u32 op, u32 right) > > } > > } > > > > +int audit_comparator64(u64 left, u32 op, u64 right) > > +{ > > + switch (op) { > > + case Audit_equal: > > + return (left == right); > > + case Audit_not_equal: > > + return (left != right); > > + case Audit_lt: > > + return (left < right); > > + case Audit_le: > > + return (left <= right); > > + case Audit_gt: > > + return (left > right); > > + case Audit_ge: > > + return (left >= right); > > + case Audit_bitmask: > > + return (left & right); > > + case Audit_bittest: > > + return ((left & right) == right); > > + default: > > + BUG(); > > + return 0; > > + } > > +} > > + > > int audit_uid_comparator(kuid_t left, u32 op, kuid_t right) > > { > > switch (op) { > > @@ -1344,6 +1387,10 @@ int audit_filter(int msgtype, unsigned int listtype) > > result = audit_comparator(audit_loginuid_set(current), > > f->op, f->val); > > break; > > + case AUDIT_CONTID: > > + result = audit_comparator64(audit_get_contid(current), > > + f->op, f->val64); > > + break; > > case AUDIT_MSGTYPE: > > result = audit_comparator(msgtype, f->op, f->val); > > break; > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > > index aa5d13b4fbbb..2d74238e9638 100644 > > --- a/kernel/auditsc.c > > +++ b/kernel/auditsc.c > > @@ -616,6 +616,9 @@ static int audit_filter_rules(struct task_struct *tsk, > > case AUDIT_LOGINUID_SET: > > result = audit_comparator(audit_loginuid_set(tsk), f->op, f->val); > > break; > > + case AUDIT_CONTID: > > + result = audit_comparator64(audit_get_contid(tsk), f->op, f->val64); > > + break; > > case AUDIT_SUBJ_USER: > > case AUDIT_SUBJ_ROLE: > > case AUDIT_SUBJ_TYPE: > > -- > > 1.8.3.1 > > > > > -- > Ondrej Mosnacek <omosnace at redhat dot com> > Associate Software Engineer, Security Technologies > Red Hat, Inc. - 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