by Richard Guy Briggs

[permalink] [raw]

Subject: [PATCH ghau51/ghau40 v9 11/11] libaudit: add support to get and set capcontid on a task

Add support to be able to set a capability to allow a task to set the
audit container identifier of descendants.

See: https://github.com/linux-audit/audit-userspace/issues/51
See: https://github.com/linux-audit/audit-kernel/issues/90
See: https://github.com/linux-audit/audit-testsuite/issues/64
See: https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID

Add the audit_get_capcontid() and audit_set_capcontid() calls analogous
to CAP_AUDIT_CONTROL for descendant user namespaces.

Signed-off-by: Richard Guy Briggs <[email protected]>
---
auparse/normalize.c | 1 +
auparse/normalize_record_map.h | 1 +
docs/Makefile.am | 1 +
docs/audit_get_capcontid.3 | 25 ++++++++++++++++
docs/audit_set_capcontid.3 | 24 +++++++++++++++
lib/libaudit.c | 68 ++++++++++++++++++++++++++++++++++++++++++
lib/libaudit.h | 4 +++
lib/msg_typetab.h | 1 +
lib/netlink.c | 1 +
src/ausearch-lol.c | 2 ++
src/ausearch-parse.c | 1 +
11 files changed, 129 insertions(+)
create mode 100644 docs/audit_get_capcontid.3
create mode 100644 docs/audit_set_capcontid.3

diff --git a/auparse/normalize.c b/auparse/normalize.c
index 2d7878ce9ba9..8bcfce280d1a 100644
--- a/auparse/normalize.c
+++ b/auparse/normalize.c
@@ -911,6 +911,7 @@ static const char *normalize_determine_evkind(int type)
case AUDIT_FEATURE_CHANGE ... AUDIT_REPLACE:
case AUDIT_USER_DEVICE:
case AUDIT_SOFTWARE_UPDATE:
+ case AUDIT_SET_CAPCONTID:
kind = NORM_EVTYPE_CONFIG;
break;
case AUDIT_SECCOMP:
diff --git a/auparse/normalize_record_map.h b/auparse/normalize_record_map.h
index 7332249c7b34..2e8c87447313 100644
--- a/auparse/normalize_record_map.h
+++ b/auparse/normalize_record_map.h
@@ -26,6 +26,7 @@
_S(AUDIT_USER, "sent-message")
_S(AUDIT_LOGIN, "changed-login-id-to")
_S(AUDIT_CONTAINER_OP, "changed-container-id-to")
+_S(AUDIT_SET_CAPCONTID, "set-capcontid-to")
_S(AUDIT_USER_AUTH, "authenticated")
_S(AUDIT_USER_ACCT, "was-authorized")
_S(AUDIT_USER_MGMT, "modified-user-account")
diff --git a/docs/Makefile.am b/docs/Makefile.am
index 209789bb2051..6b981b296d0c 100644
--- a/docs/Makefile.am
+++ b/docs/Makefile.am
@@ -29,6 +29,7 @@ auditd.conf.5 auditd-plugins.5 \
audit_delete_rule_data.3 audit_detect_machine.3 \
audit_encode_nv_string.3 audit_getloginuid.3 \
audit_get_reply.3 audit_get_session.3 audit_get_containerid.3 \
+audit_get_capcontid.3 audit_set_capcontid.3 \
audit_log_acct_message.3 audit_log_user_avc_message.3 \
audit_log_user_command.3 audit_log_user_comm_message.3 \
audit_log_user_message.3 audit_log_semanage_message.3 \
diff --git a/docs/audit_get_capcontid.3 b/docs/audit_get_capcontid.3
new file mode 100644
index 000000000000..652a4960a020
--- /dev/null
+++ b/docs/audit_get_capcontid.3
@@ -0,0 +1,25 @@
+.TH "AUDIT_GET_CAPCONTID" "26" "Aug 2019" "Red Hat" "Linux Audit API"
+.SH NAME
+audit_get_capcontid \- Get a program's capability container id value
+.SH SYNOPSIS
+.B #include <libaudit.h>
+.sp
+int audit_get_capcontid(pid_t pid);
+
+.SH DESCRIPTION
+This function returns the pid task's audit capability container identifier attribute.
+
+.SH "RETURN VALUE"
+
+This function returns the audit capability container identifier value if it is implemented. It will return a \-1 if the audit capability container identifier is unavailable.
+
+.SH "ERRORS"
+
+This function returns \-2 on failure. Additionally, in the event of a real error, errno would be set. The function can set errno based on failures of open, read, or strtoull.
+
+.SH "SEE ALSO"
+
+.BR audit_set_capcontid (3).
+
+.SH AUTHOR
+Richard Guy Briggs
diff --git a/docs/audit_set_capcontid.3 b/docs/audit_set_capcontid.3
new file mode 100644
index 000000000000..70ac8c7a4e95
--- /dev/null
+++ b/docs/audit_set_capcontid.3
@@ -0,0 +1,24 @@
+.TH "AUDIT_SET_CAPCONTID" "26" "Aug 2019" "Red Hat" "Linux Audit API"
+.SH NAME
+audit_set_capcontid \- Set a program's capability container id value
+.SH SYNOPSIS
+.B #include <libaudit.h>
+.sp
+int audit_set_capcontid(pid_t pid, uint32_t capcontid);
+
+.SH "DESCRIPTION"
+
+This function sets the pid task's attribute capability container id with the value of capcontid. The capcontid value may only be set by programs with the CAP_AUDIT_CONTROL capability in the initial user namespace or with capcontid. This normally means the root account or root in a container.
+.sp
+The capcontid value is part of the task structure and is inheritted by child processes within a user namespace. It is used to enable the capability to set container identifier of a child task in a descendent user namespace. Container orchestrator/engines should set this value only on children it wishes to be able to set audit container identifiers.
+
+.SH "RETURN VALUE"
+
+This function returns 0 on success and non-zero otherwise.
+
+.SH "SEE ALSO"
+
+.BR audit_get_capcontid (3).
+
+.SH AUTHOR
+Richard Guy Briggs
diff --git a/lib/libaudit.c b/lib/libaudit.c
index 1a7fed76b9b0..4a2678ca2171 100644
--- a/lib/libaudit.c
+++ b/lib/libaudit.c
@@ -992,6 +992,74 @@ uint32_t audit_get_session(void)
}

/*
+ * This function will retrieve the capability container identifier or -2 if
+ * there is an error.
+ */
+uint32_t audit_get_capcontid(pid_t pid)
+{
+ int capcontid;
+ int len, in;
+ char buf[16], fnbuf[48];
+
+ if ((audit_get_features() & AUDIT_FEATURE_BITMAP_CONTAINERID) == 0)
+ return -2;
+ errno = 0;
+ snprintf(fnbuf, sizeof(fnbuf), "/proc/%d/audit_capcontainerid", pid);
+ in = open(fnbuf, O_NOFOLLOW|O_RDONLY);
+ if (in < 0)
+ return -2;
+ do {
+ len = read(in, buf, sizeof(buf));
+ } while (len < 0 && errno == EINTR);
+ close(in);
+ if (len < 0 || len >= sizeof(buf))
+ return -2;
+ buf[len] = 0;
+ errno = 0;
+ capcontid = strtol(buf, 0, 10);
+ if (errno)
+ return -2;
+ return capcontid;
+}
+
+/*
+ * This function returns 0 on success and 1 on failure
+ */
+int audit_set_capcontid(pid_t pid, uint32_t capcontid)
+{
+ char capcontidbuf[16], fnbuf[48];
+ int o, count, rc = 0;
+
+ if ((audit_get_features() & AUDIT_FEATURE_BITMAP_CONTAINERID) == 0)
+ return -2;
+ errno = 0;
+ count = snprintf(capcontidbuf, sizeof(capcontidbuf), "%u", capcontid);
+ snprintf(fnbuf, sizeof(fnbuf), "/proc/%d/audit_capcontainerid", pid);
+ o = open(fnbuf, O_NOFOLLOW|O_WRONLY|O_TRUNC);
+ if (o >= 0) {
+ int block, offset = 0;
+
+ while (count > 0) {
+ block = write(o, &capcontidbuf[offset], (unsigned int)count);
+ if (block < 0) {
+ if (errno == EINTR)
+ continue;
+ audit_msg(LOG_ERR, "Error writing capcontid");
+ close(o);
+ return 1;
+ }
+ offset += block;
+ count -= block;
+ }
+ close(o);
+ } else {
+ audit_msg(LOG_ERR, "Error opening %s", fnbuf);
+ rc = 1;
+ }
+ return rc;
+}
+
+/*
* This function will retrieve the audit container identifier or -2 if
* there is an error.
*/
diff --git a/lib/libaudit.h b/lib/libaudit.h
index f4e820e9b097..2a140f6d0e4b 100644
--- a/lib/libaudit.h
+++ b/lib/libaudit.h
@@ -255,6 +255,10 @@ extern "C" {
#define AUDIT_SIGNAL_INFO2 1021 /* auditd signal sender info */
#endif

+#ifndef AUDIT_SET_CAPCONTID
+#define AUDIT_SET_CAPCONTID 1022 /* set capcontid of specified pid */
+#endif
+
#ifndef AUDIT_MMAP
#define AUDIT_MMAP 1323 /* Descriptor and flags in mmap */
#endif
diff --git a/lib/msg_typetab.h b/lib/msg_typetab.h
index e904ece158ce..453013bf434f 100644
--- a/lib/msg_typetab.h
+++ b/lib/msg_typetab.h
@@ -46,6 +46,7 @@ _S(AUDIT_LOGIN, "LOGIN" )
//_S(AUDIT_GET_FEATURE, "GET_FEATURE" )
//_S(AUDIT_SIGNAL_INFO2, "SIGNAL_INFO2" )
_S(AUDIT_CONTAINER_OP, "CONTAINER_OP" )
+_S(AUDIT_SET_CAPCONTID, "SET_CAPCONTID" )
_S(AUDIT_USER_AUTH, "USER_AUTH" )
_S(AUDIT_USER_ACCT, "USER_ACCT" )
_S(AUDIT_USER_MGMT, "USER_MGMT" )
diff --git a/lib/netlink.c b/lib/netlink.c
index 66a3a3b7e83c..d7c3c6124a68 100644
--- a/lib/netlink.c
+++ b/lib/netlink.c
@@ -186,6 +186,7 @@ static int adjust_reply(struct audit_reply *rep, int len)
case AUDIT_USER:
case AUDIT_LOGIN:
case AUDIT_CONTAINER_OP:
+ case AUDIT_SET_CAPCONTID:
case AUDIT_KERNEL:
case AUDIT_FIRST_USER_MSG...AUDIT_LAST_USER_MSG:
case AUDIT_FIRST_USER_MSG2...AUDIT_LAST_USER_MSG2:
diff --git a/src/ausearch-lol.c b/src/ausearch-lol.c
index 05fe80fe3ad6..8ad88a14f30c 100644
--- a/src/ausearch-lol.c
+++ b/src/ausearch-lol.c
@@ -250,6 +250,8 @@ static void check_events(lol *lo, time_t sec)
(cur->l->e.type > AUDIT_LOGIN &&
cur->l->e.type < AUDIT_CONTAINER_OP ) ||
(cur->l->e.type > AUDIT_CONTAINER_OP &&
+ cur->l->e.type < AUDIT_SET_CAPCONTID ) ||
+ (cur->l->e.type > AUDIT_SET_CAPCONTID &&
cur->l->e.type < AUDIT_FIRST_EVENT ) ||
cur->l->e.type == AUDIT_PROCTITLE ||
(cur->l->e.type >= AUDIT_MAC_UNLBL_ALLOW &&
diff --git a/src/ausearch-parse.c b/src/ausearch-parse.c
index 93482be3606e..9d8a5dd2d092 100644
--- a/src/ausearch-parse.c
+++ b/src/ausearch-parse.c
@@ -192,6 +192,7 @@ int extract_search_items(llist *l)
case AUDIT_MMAP:
case AUDIT_PROCTITLE:
case AUDIT_REPLACE...AUDIT_BPF:
+ case AUDIT_SET_CAPCONTID:
// Nothing to parse
break;
case AUDIT_NETFILTER_CFG:
--
1.8.3.1