Re: [RFC PATCH ghak32 V2 04/13] audit: add containerid filtering

On Fri, Mar 16, 2018 at 5:00 AM, Richard Guy Briggs <rgb(a)redhat.com&gt; wrote: > Implement container ID filtering using the AUDIT_CONTAINERID 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. My only worry here is that you aren't really sending a string in the ASCII sense, you are sending an 8 byte buffer (that better be NUL terminated) that happens to be an unsigned 64-bit integer. To be clear, I'm okay with that (it's protected by AUDIT_CONTAINERID), and the code is okay with that, I just want us to pause for a minute and make sure that is an okay thing to do long term.

> The feature indicator is AUDIT_FEATURE_BITMAP_CONTAINERID_FILTER. > > This requires support from userspace to be useful. > See: https://github.com/linux-audit/audit-userspace/issues/40 > Signed-off-by: Richard Guy Briggs <rgb(a)redhat.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 3acbe9d..f10ca1b 100644 > --- a/include/linux/audit.h > +++ b/include/linux/audit.h > @@ -76,6 +76,7 @@ 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 e83ccbd..8443a8f 100644 > --- a/include/uapi/linux/audit.h > +++ b/include/uapi/linux/audit.h > @@ -262,6 +262,7 @@ > #define AUDIT_LOGINUID_SET 24 > #define AUDIT_SESSIONID 25 /* Session ID */ > #define AUDIT_FSTYPE 26 /* FileSystem Type */ > +#define AUDIT_CONTAINERID 27 /* Container ID */ > > /* These are ONLY useful when checking > * at syscall exit time (AUDIT_AT_EXIT). */ > @@ -342,6 +343,7 @@ 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_FILTER 0x00000080 > > #define AUDIT_FEATURE_BITMAP_ALL (AUDIT_FEATURE_BITMAP_BACKLOG_LIMIT | \ > AUDIT_FEATURE_BITMAP_BACKLOG_WAIT_TIME | \ > @@ -349,7 +351,8 @@ 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_FILTER) > > /* deprecated: AUDIT_VERSION_* */ > #define AUDIT_VERSION_LATEST AUDIT_FEATURE_BITMAP_ALL > diff --git a/kernel/audit.h b/kernel/audit.h > index 214e149..aaa651a 100644 > --- a/kernel/audit.h > +++ b/kernel/audit.h > @@ -234,6 +234,7 @@ 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 d7a807e..c4c8746 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_CONTAINERID: > if (f->op != Audit_not_equal && f->op != Audit_equal) > return -EINVAL; > break; > @@ -584,6 +585,14 @@ static struct audit_entry *audit_data_to_entry(struct audit_rule_data *data, > } > entry->rule.exe = audit_mark; > break; > + case AUDIT_CONTAINERID: > + 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; > } > } > > @@ -666,6 +675,11 @@ 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_CONTAINERID: > + data->buflen += data->values[i] = sizeof(u64); > + for (i = 0; i < sizeof(u64); i++) > + ((char *)bufp)[i] = ((char *)&f->val64)[i]; > + break; > case AUDIT_LOGINUID_SET: > if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) { > data->fields[i] = AUDIT_LOGINUID; > @@ -752,6 +766,10 @@ 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_CONTAINERID: > + if (a->fields[i].val64 != b->fields[i].val64) > + return 1; > + break; > default: > if (a->fields[i].val != b->fields[i].val) > return 1; > @@ -1210,6 +1228,31 @@ 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) { > @@ -1348,6 +1391,10 @@ int audit_filter(int msgtype, unsigned int listtype) > result = audit_comparator(audit_loginuid_set(current), > f->op, f->val); > break; > + case AUDIT_CONTAINERID: > + result = audit_comparator64(audit_get_containerid(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 65be110..2bba324 100644 > --- a/kernel/auditsc.c > +++ b/kernel/auditsc.c > @@ -614,6 +614,9 @@ 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_CONTAINERID: > + result = audit_comparator64(audit_get_containerid(tsk), f->op, f->val64); > + break; > case AUDIT_SUBJ_USER: > case AUDIT_SUBJ_ROLE: > case AUDIT_SUBJ_TYPE: > -- > 1.8.3.1 > > -- > Linux-audit mailing list > Linux-audit(a)redhat.com > https://www.redhat.com/mailman/listinfo/linux-audit -- paul moore www.paul-moore.com