Discussion:
[RFC PATCH] auditctl: add support for containerid filter
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Richard Guy Briggs
2018-03-05 08:06:06 UTC
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A u64 container identifier has been added to the kernel view of tasks.
This allows container orchestrators to label tasks with a unique
tamperproof identifier that gets inherited by its children to be able to
track the provenance of actions by a container.

Add support to libaudit and auditctl for the containerid field to filter
based on container identifier. Since it is a u64 and larger than any
other numeric field, send it as a string but do the appropriate
conversions on each end in each direction.

See: https://github.com/linux-audit/audit-userspace/issues/40
See: https://github.com/linux-audit/audit-kernel/issues/32
See: https://github.com/linux-audit/audit-testsuite/issues/64
Signed-off-by: Richard Guy Briggs <***@redhat.com>
---
Note: This is a userspace patch for the audit utils to support the
kernel RFC patchset, in optimism of kernel support acceptance.
ausearch would also need support added.
---
docs/auditctl.8 | 3 +++
lib/fieldtab.h | 1 +
lib/libaudit.c | 36 ++++++++++++++++++++++++++++++++++++
lib/libaudit.h | 7 +++++++
src/auditctl-listing.c | 21 +++++++++++++++++++++
5 files changed, 68 insertions(+)

diff --git a/docs/auditctl.8 b/docs/auditctl.8
index 88466de..8bda43d 100644
--- a/docs/auditctl.8
+++ b/docs/auditctl.8
@@ -210,6 +210,9 @@ Parent's Process ID
.B sessionid
User's login session ID
.TP
+.B containerid
+Process' container ID
+.TP
.B subj_user
Program's SE Linux User
.TP
diff --git a/lib/fieldtab.h b/lib/fieldtab.h
index c425d5b..755800a 100644
--- a/lib/fieldtab.h
+++ b/lib/fieldtab.h
@@ -47,6 +47,7 @@ _S(AUDIT_OBJ_TYPE, "obj_type" )
_S(AUDIT_OBJ_LEV_LOW, "obj_lev_low" )
_S(AUDIT_OBJ_LEV_HIGH, "obj_lev_high" )
_S(AUDIT_SESSIONID, "sessionid" )
+_S(AUDIT_CONTAINERID, "containerid" )

_S(AUDIT_DEVMAJOR, "devmajor" )
_S(AUDIT_DEVMINOR, "devminor" )
diff --git a/lib/libaudit.c b/lib/libaudit.c
index aa8258c..2e01a22 100644
--- a/lib/libaudit.c
+++ b/lib/libaudit.c
@@ -1737,6 +1737,42 @@ int audit_rule_fieldpair_data(struct audit_rule_data **rulep, const char *pair,
else if (strcmp(v, "unset") == 0)
rule->values[rule->field_count] = 4294967295;
break;
+ case AUDIT_CONTAINERID: {
+ unsigned long long val;
+
+ if ((audit_get_features() &
+ AUDIT_FEATURE_BITMAP_CONTAINERID_FILTER) == 0)
+ return -EAU_FIELDNOSUPPORT;
+ if (flags != AUDIT_FILTER_EXCLUDE &&
+ flags != AUDIT_FILTER_USER &&
+ flags != AUDIT_FILTER_EXIT)
+ return -EAU_FIELDNOFILTER;
+ if (isdigit((char)*(v)))
+ val = strtoull(v, NULL, 0);
+ else if (strlen(v) >= 2 && *(v)=='-' &&
+ (isdigit((char)*(v+1))))
+ val = strtoll(v, NULL, 0);
+ else if (strcmp(v, "unset") == 0)
+ val = ULLONG_MAX;
+ else
+ return -EAU_FIELDVALNUM;
+ if (errno)
+ return -EAU_FIELDVALNUM;
+ vlen = sizeof(unsigned long long);
+ rule->values[rule->field_count] = vlen;
+ offset = rule->buflen;
+ rule->buflen += vlen;
+ *rulep = realloc(rule, sizeof(*rule) + rule->buflen);
+ if (*rulep == NULL) {
+ free(rule);
+ audit_msg(LOG_ERR, "Cannot realloc memory!\n");
+ return -3;
+ } else {
+ rule = *rulep;
+ }
+ *(unsigned long long*)(&rule->buf[offset]) = val;
+ break;
+ }
case AUDIT_DEVMAJOR...AUDIT_INODE:
case AUDIT_SUCCESS:
if (flags != AUDIT_FILTER_EXIT)
diff --git a/lib/libaudit.h b/lib/libaudit.h
index b681e8d..542ec62 100644
--- a/lib/libaudit.h
+++ b/lib/libaudit.h
@@ -320,6 +320,9 @@ extern "C" {
#ifndef AUDIT_FEATURE_BITMAP_FILTER_FS
#define AUDIT_FEATURE_BITMAP_FILTER_FS 0x00000040
#endif
+#ifndef AUDIT_FEATURE_BITMAP_CONTAINERID_FILTER
+#define AUDIT_FEATURE_BITMAP_CONTAINERID_FILTER 0x00000080
+#endif

/* Defines for interfield comparison update */
#ifndef AUDIT_OBJ_UID
@@ -343,6 +346,10 @@ extern "C" {
#define AUDIT_FSTYPE 26
#endif

+#ifndef AUDIT_CONTAINERID
+#define AUDIT_CONTAINERID 27
+#endif
+
#ifndef AUDIT_COMPARE_UID_TO_OBJ_UID
#define AUDIT_COMPARE_UID_TO_OBJ_UID 1
#endif
diff --git a/src/auditctl-listing.c b/src/auditctl-listing.c
index f670ff9..974dcb4 100644
--- a/src/auditctl-listing.c
+++ b/src/auditctl-listing.c
@@ -25,6 +25,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <limits.h>
#include "auditctl-listing.h"
#include "private.h"
#include "auditctl-llist.h"
@@ -460,6 +461,26 @@ static void print_rule(const struct audit_rule_data *r)
audit_operator_to_symbol(op),
audit_fstype_to_name(
r->values[i]));
+ } else if (field == AUDIT_CONTAINERID) {
+ unsigned long long val;
+
+ if (r->values[i] == sizeof(unsigned long long)) {
+ val = *(unsigned long long*)(&r->buf[boffset]);
+
+ if (val != ULLONG_MAX)
+ printf(" -F %s%s%llu", name,
+ audit_operator_to_symbol(op),
+ val);
+ else
+ printf(" -F %s%s%s", name,
+ audit_operator_to_symbol(op),
+ "unset");
+ } else {
+ printf(" -F %s%s%s", name,
+ audit_operator_to_symbol(op),
+ "inval");
+ }
+ boffset += r->values[i];
} else {
// The default is signed decimal
printf(" -F %s%s%d", name,
--
1.8.3.1
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