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

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().

Also, doesn't this loop interfere with the outer loop that also uses 'i' as the control variable?

> + 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.