[PATCH ghak90 V8 00/16] audit: implement container identifier
by Richard Guy Briggs
Implement kernel audit container identifier.
This patchset is an eighth based on the proposal document (V4) posted:
https://www.redhat.com/archives/linux-audit/2019-September/msg00052.html
The first patch was the last patch from ghak81 that was absorbed into
this patchset since its primary justification is the rest of this
patchset.
The second patch implements the proc fs write to set the audit container
identifier of a process, emitting an AUDIT_CONTAINER_OP record to
announce the registration of that audit container identifier on that
process. This patch requires userspace support for record acceptance
and proper type display.
The third implements reading the audit container identifier from the
proc filesystem for debugging. This patch wasn't planned for upstream
inclusion but is starting to become more likely.
The fourth converts over from a simple u64 to a list member that includes
owner information to check for descendancy, allow process injection into
a container and prevent id reuse by other orchestrators.
The fifth logs the drop of an audit container identifier once all tasks
using that audit container identifier have exited.
The 6th implements the auxiliary record AUDIT_CONTAINER_ID if an audit
container identifier is associated with an event. This patch requires
userspace support for proper type display.
The 7th adds audit daemon signalling provenance through audit_sig_info2.
The 8th creates a local audit context to be able to bind a standalone
record with a locally created auxiliary record.
The 9th patch adds audit container identifier records to the user
standalone records.
The 10th adds audit container identifier filtering to the exit,
exclude and user lists. This patch adds the AUDIT_CONTID field and
requires auditctl userspace support for the --contid option.
The 11th adds network namespace audit container identifier labelling
based on member tasks' audit container identifier labels which supports
standalone netfilter records that don't have a task context and lists
each container to which that net namespace belongs.
The 12th checks that the target is a descendant for nesting and
refactors to avoid a duplicate of the copied function.
The 13th adds tracking and reporting for container nesting.
This enables kernel filtering and userspace searches of nested audit
container identifiers.
The 14th checks and clamps the nesting depth of containers while the
15th checks and clamps the total number of audit container identifiers
sharing one network namespace. The combination of these two pararmeters
prevents the overflow of the contid field in CONTAINER_* records.
The 16th adds a mechanism to allow a process to be designated as a
container orchestrator/engine in non-init user namespaces.
Example: Set an audit container identifier of 123456 to the "sleep" task:
sleep 2&
child=$!
echo 123456 > /proc/$child/audit_containerid; echo $?
ausearch -ts recent -m container_op
echo child:$child contid:$( cat /proc/$child/audit_containerid)
This should produce a record such as:
type=CONTAINER_OP msg=audit(2018-06-06 12:39:29.636:26949) : op=set opid=2209 contid=123456 old-contid=18446744073709551615
Example: Set a filter on an audit container identifier 123459 on /tmp/tmpcontainerid:
contid=123459
key=tmpcontainerid
auditctl -a exit,always -F dir=/tmp -F perm=wa -F contid=$contid -F key=$key
perl -e "sleep 1; open(my \$tmpfile, '>', \"/tmp/$key\"); close(\$tmpfile);" &
child=$!
echo $contid > /proc/$child/audit_containerid
sleep 2
ausearch -i -ts recent -k $key
auditctl -d exit,always -F dir=/tmp -F perm=wa -F contid=$contid -F key=$key
rm -f /tmp/$key
This should produce an event such as:
type=CONTAINER_ID msg=audit(2018-06-06 12:46:31.707:26953) : contid=123459
type=PROCTITLE msg=audit(2018-06-06 12:46:31.707:26953) : proctitle=perl -e sleep 1; open(my $tmpfile, '>', "/tmp/tmpcontainerid"); close($tmpfile);
type=PATH msg=audit(2018-06-06 12:46:31.707:26953) : item=1 name=/tmp/tmpcontainerid inode=25656 dev=00:26 mode=file,644 ouid=root ogid=root rdev=00:00 obj=unconfined_u:object_r:user_tmp_t:s0 nametype=CREATE cap_fp=none cap_fi=none cap_fe=0 cap_fver=0
type=PATH msg=audit(2018-06-06 12:46:31.707:26953) : item=0 name=/tmp/ inode=8985 dev=00:26 mode=dir,sticky,777 ouid=root ogid=root rdev=00:00 obj=system_u:object_r:tmp_t:s0 nametype=PARENT cap_fp=none cap_fi=none cap_fe=0 cap_fver=0
type=CWD msg=audit(2018-06-06 12:46:31.707:26953) : cwd=/root
type=SYSCALL msg=audit(2018-06-06 12:46:31.707:26953) : arch=x86_64 syscall=openat success=yes exit=3 a0=0xffffffffffffff9c a1=0x5621f2b81900 a2=O_WRONLY|O_CREAT|O_TRUNC a3=0x1b6 items=2 ppid=628 pid=2232 auid=root uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=ttyS0 ses=1 comm=perl exe=/usr/bin/perl subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=tmpcontainerid
Example: Test multiple containers on one netns:
sleep 5 &
child1=$!
containerid1=123451
echo $containerid1 > /proc/$child1/audit_containerid
sleep 5 &
child2=$!
containerid2=123452
echo $containerid2 > /proc/$child2/audit_containerid
iptables -I INPUT -i lo -p icmp --icmp-type echo-request -j AUDIT --type accept
iptables -I INPUT -t mangle -i lo -p icmp --icmp-type echo-request -j MARK --set-mark 0x12345555
sleep 1;
bash -c "ping -q -c 1 127.0.0.1 >/dev/null 2>&1"
sleep 1;
ausearch -i -m NETFILTER_PKT -ts boot|grep mark=0x12345555
ausearch -i -m NETFILTER_PKT -ts boot|grep contid=|grep $containerid1|grep $containerid2
This should produce an event such as:
type=NETFILTER_PKT msg=audit(03/15/2019 14:16:13.369:244) : mark=0x12345555 saddr=127.0.0.1 daddr=127.0.0.1 proto=icmp
type=CONTAINER_ID msg=audit(03/15/2019 14:16:13.369:244) : contid=123452,123451
Includes the last patch of https://github.com/linux-audit/audit-kernel/issues/81
Please see the github audit kernel issue for the main feature:
https://github.com/linux-audit/audit-kernel/issues/90
and the kernel filter code:
https://github.com/linux-audit/audit-kernel/issues/91
and the network support:
https://github.com/linux-audit/audit-kernel/issues/92
Please see the github audit userspace issue for supporting record types:
https://github.com/linux-audit/audit-userspace/issues/51
and filter code:
https://github.com/linux-audit/audit-userspace/issues/40
Please see the github audit testsuiite issue for the test case:
https://github.com/linux-audit/audit-testsuite/issues/64
https://github.com/rgbriggs/audit-testsuite/tree/ghat64-contid
https://githu.com/linux-audit/audit-testsuite/pull/91
Please see the github audit wiki for the feature overview:
https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Container-ID
The code is also posted at:
git://toccata2.tricolour.ca/linux-2.6-rgb.git ghak90-audit-containerID.v8
Changelog:
v8
- rebase on v5.5-rc1 audit/next
- remove subject attrs in CONTAINER_OP record
- group audit_contid_list_lock with audit_contid_hash
- in audit_{set,log}_contid(), break out of loop after finding target
- use target var to size kmalloc
- rework audit_cont_owner() to bool audit_contid_isowner() and move to where used
- create static void audit_cont_hold(struct audit_contobj *cont) { refcount_inc(&cont->refcount); }
- rename audit_cont{,_*} refs to audit_contobj{,_*}
- prefix special local functions with _ [audit_contobj*()]
- protect contid list traversals with rcu_read_lock() and updates with audit_contid_list_lock
- protect real_parent in audit_contid_depth() with rcu_dereference
- give new contid field nesting format in patch description
- squash task_is_descendant()
- squash support for NETFILTER_PKT into network namespaces
- limit nesting depth based on record length overflow, bandwidth and storage
- implent control for audit container identifier nesting depth limit
- make room for audit_bpf patches (bump CONTAINER_ID to 1335)
- squash proc interface into capcontid
- remove netlink access to loginuid/sessionid/contid/capcontid
- delete 32k contid limit patch
- document potential overlap between signal delivery and contid reuse
- document audit_contobj_list_lock coverage
- document disappearing orch task injection limitation
- limit the number of containers that can be associated with a network namespace
- implent control for audit container identifier netns count limit
v7
- remove BUG() in audit_comparator64()
- rebase on v5.2-rc1 audit/next
- resolve merge conflict with ghak111 (signal_info regardless syscall)
- resolve merge conflict with ghak73 (audit_field_valid)
- resolve merge conflict with ghak64 (saddr_fam filter)
- resolve merge conflict with ghak10 (ntp audit) change AUDIT_CONTAINER_ID from 1332 to 1334
- rebase on v5.3-rc1 audit/next
- track container owner
- only permit setting contid of descendants for nesting
- track drop of contid and permit reuse
- track and report container nesting
- permit filtering on any nested contid
- set/get contid and loginuid/sessionid via netlink
- implement capcontid to enable orchestrators in non-init user
namespaces
- limit number of containers
- limit depth of container nesting
v6
- change TMPBUFLEN from 11 to 21 to cover the decimal value of contid
u64 (nhorman)
- fix bug overwriting ctx in struct audit_sig_info, move cid above
ctx[0] (nhorman)
- fix bug skipping remaining fields and not advancing bufp when copying
out contid in audit_krule_to_data (omosnacec)
- add acks, tidy commit descriptions, other formatting fixes (checkpatch
wrong on audit_log_lost)
- cast ull for u64 prints
- target_cid tracking was moved from the ptrace/signal patch to
container_op
- target ptrace and signal records were moved from the ptrace/signal
patch to container_id
- auditd signaller tracking was moved to a new AUDIT_SIGNAL_INFO2
request and record
- ditch unnecessary list_empty() checks
- check for null net and aunet in audit_netns_contid_add()
- swap CONTAINER_OP contid/old-contid order to ease parsing
v5
- address loginuid and sessionid syscall scope in ghak104
- address audit_context in CONFIG_AUDIT vs CONFIG_AUDITSYSCALL in ghak105
- remove tty patch, addressed in ghak106
- rebase on audit/next v5.0-rc1
w/ghak59/ghak104/ghak103/ghak100/ghak107/ghak105/ghak106/ghak105sup
- update CONTAINER_ID to CONTAINER_OP in patch description
- move audit_context in audit_task_info to CONFIG_AUDITSYSCALL
- move audit_alloc() and audit_free() out of CONFIG_AUDITSYSCALL and into
CONFIG_AUDIT and create audit_{alloc,free}_syscall
- use plain kmem_cache_alloc() rather than kmem_cache_zalloc() in audit_alloc()
- fix audit_get_contid() declaration type error
- move audit_set_contid() from auditsc.c to audit.c
- audit_log_contid() returns void
- audit_log_contid() handed contid rather than tsk
- switch from AUDIT_CONTAINER to AUDIT_CONTAINER_ID for aux record
- move audit_log_contid(tsk/contid) & audit_contid_set(tsk)/audit_contid_valid(contid)
- switch from tsk to current
- audit_alloc_local() calls audit_log_lost() on failure to allocate a context
- add AUDIT_USER* non-syscall contid record
- cosmetic cleanup double parens, goto out on err
- ditch audit_get_ns_contid_list_lock(), fix aunet lock race
- switch from all-cpu read spinlock to rcu, keep spinlock for write
- update audit_alloc_local() to use ktime_get_coarse_real_ts64()
- add nft_log support
- add call from do_exit() in audit_free() to remove contid from netns
- relegate AUDIT_CONTAINER ref= field (was op=) to debug patch
v4
- preface set with ghak81:"collect audit task parameters"
- add shallyn and sgrubb acks
- rename feature bitmap macro
- rename cid_valid() to audit_contid_valid()
- rename AUDIT_CONTAINER_ID to AUDIT_CONTAINER_OP
- delete audit_get_contid_list() from headers
- move work into inner if, delete "found"
- change netns contid list function names
- move exports for audit_log_contid audit_alloc_local audit_free_context to non-syscall patch
- list contids CSV
- pass in gfp flags to audit_alloc_local() (fix audit_alloc_context callers)
- use "local" in lieu of abusing in_syscall for auditsc_get_stamp()
- read_lock(&tasklist_lock) around children and thread check
- task_lock(tsk) should be taken before first check of tsk->audit
- add spin lock to contid list in aunet
- restrict /proc read to CAP_AUDIT_CONTROL
- remove set again prohibition and inherited flag
- delete contidion spelling fix from patchset, send to netdev/linux-wireless
v3
- switched from containerid in task_struct to audit_task_info (depends on ghak81)
- drop INVALID_CID in favour of only AUDIT_CID_UNSET
- check for !audit_task_info, throw -ENOPROTOOPT on set
- changed -EPERM to -EEXIST for parent check
- return AUDIT_CID_UNSET if !audit_enabled
- squash child/thread check patch into AUDIT_CONTAINER_ID patch
- changed -EPERM to -EBUSY for child check
- separate child and thread checks, use -EALREADY for latter
- move addition of op= from ptrace/signal patch to AUDIT_CONTAINER patch
- fix && to || bashism in ptrace/signal patch
- uninline and export function for audit_free_context()
- drop CONFIG_CHANGE, FEATURE_CHANGE, ANOM_ABEND, ANOM_SECCOMP patches
- move audit_enabled check (xt_AUDIT)
- switched from containerid list in struct net to net_generic's struct audit_net
- move containerid list iteration into audit (xt_AUDIT)
- create function to move namespace switch into audit
- switched /proc/PID/ entry from containerid to audit_containerid
- call kzalloc with GFP_ATOMIC on in_atomic() in audit_alloc_context()
- call kzalloc with GFP_ATOMIC on in_atomic() in audit_log_container_info()
- use xt_net(par) instead of sock_net(skb->sk) to get net
- switched record and field names: initial CONTAINER_ID, aux CONTAINER, field CONTID
- allow to set own contid
- open code audit_set_containerid
- add contid inherited flag
- ccontainerid and pcontainerid eliminated due to inherited flag
- change name of container list funcitons
- rename containerid to contid
- convert initial container record to syscall aux
- fix spelling mistake of contidion in net/rfkill/core.c to avoid contid name collision
v2
- add check for children and threads
- add network namespace container identifier list
- add NETFILTER_PKT audit container identifier logging
- patch description and documentation clean-up and example
- reap unused ppid
Richard Guy Briggs (16):
audit: collect audit task parameters
audit: add container id
audit: read container ID of a process
audit: convert to contid list to check for orch/engine ownership
audit: log drop of contid on exit of last task
audit: log container info of syscalls
audit: add contid support for signalling the audit daemon
audit: add support for non-syscall auxiliary records
audit: add containerid support for user records
audit: add containerid filtering
audit: add support for containerid to network namespaces
audit: contid check descendancy and nesting
audit: track container nesting
audit: check contid depth and add limit config param
audit: check contid count per netns and add config param limit
audit: add capcontid to set contid outside init_user_ns
fs/proc/base.c | 112 +++++++-
include/linux/audit.h | 140 +++++++++-
include/linux/nsproxy.h | 2 +-
include/linux/sched.h | 10 +-
include/uapi/linux/audit.h | 14 +-
init/init_task.c | 3 +-
init/main.c | 2 +
kernel/audit.c | 626 +++++++++++++++++++++++++++++++++++++++++++-
kernel/audit.h | 29 ++
kernel/auditfilter.c | 61 +++++
kernel/auditsc.c | 91 +++++--
kernel/fork.c | 11 +-
kernel/nsproxy.c | 27 +-
kernel/sched/core.c | 33 +++
net/netfilter/nft_log.c | 11 +-
net/netfilter/xt_AUDIT.c | 11 +-
security/selinux/nlmsgtab.c | 1 +
security/yama/yama_lsm.c | 33 ---
18 files changed, 1115 insertions(+), 102 deletions(-)
--
1.8.3.1
3 years, 11 months
[PATCH] audit: mark expected switch fall-through
by Gustavo A. R. Silva
In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.
This patch fixes the following warning:
kernel/auditfilter.c: In function ‘audit_krule_to_data’:
kernel/auditfilter.c:668:7: warning: this statement may fall through [-Wimplicit-fallthrough=]
if (krule->pflags & AUDIT_LOGINUID_LEGACY && !f->val) {
^
kernel/auditfilter.c:674:3: note: here
default:
^~~~~~~
Warning level 3 was used: -Wimplicit-fallthrough=3
Notice that, in this particular case, the code comment is modified
in accordance with what GCC is expecting to find.
This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough.
Signed-off-by: Gustavo A. R. Silva <gustavo(a)embeddedor.com>
---
kernel/auditfilter.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index add360b46b38..63f8b3f26fab 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -670,7 +670,7 @@ static struct audit_rule_data *audit_krule_to_data(struct audit_krule *krule)
data->values[i] = AUDIT_UID_UNSET;
break;
}
- /* fallthrough if set */
+ /* fall through - if set */
default:
data->values[i] = f->val;
}
--
2.20.1
4 years
[PATCH ghak28 V7] audit: log audit netlink multicast bind and unbind events
by Richard Guy Briggs
Log information about programs connecting to and disconnecting from the
audit netlink multicast socket. This is needed so that during
investigations a security officer can tell who or what had access to the
audit trail. This helps to meet the FAU_SAR.2 requirement for Common
Criteria. Here is the systemd startup event:
type=PROCTITLE msg=audit(2020-02-18 15:26:50.775:10) : proctitle=/init
type=SYSCALL msg=audit(2020-02-18 15:26:50.775:10) : arch=x86_64 syscall=bind success=yes exit=0 a0=0x19 a1=0x55645c369b70 a2=0xc a3=0x7fff9fedec24 items=0 ppid=0 pid=1 auid=unset uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=(none) ses=unset comm=systemd exe=/usr/lib/systemd/systemd subj=kernel key=(null)
type=UNKNOWN[1335] msg=audit(2020-02-18 15:26:50.775:10) : pid=1 uid=root auid=unset tty=(none) ses=unset subj=kernel comm=systemd exe=/usr/lib/systemd/systemd nl-mcgrp=1 op=connect res=yes
And the events from the test suite:
type=PROCTITLE msg=audit(2020-02-18 15:28:01.594:307) : proctitle=/usr/bin/perl -w amcast_joinpart/test
type=SYSCALL msg=audit(2020-02-18 15:28:01.594:307) : arch=x86_64 syscall=bind success=yes exit=0 a0=0x7 a1=0x558ebc428be0 a2=0xc a3=0x0 items=0 ppid=642 pid=645 auid=root uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=ttyS0 ses=1 comm=perl exe=/usr/bin/perl subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)
type=UNKNOWN[1335] msg=audit(2020-02-18 15:28:01.594:307) : pid=645 uid=root auid=root tty=ttyS0 ses=1 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 comm=perl exe=/usr/bin/perl nl-mcgrp=1 op=connect res=yes
type=PROCTITLE msg=audit(2020-03-17 11:35:31.474:344) : proctitle=/usr/bin/perl -w amcast_joinpart/test
type=SYSCALL msg=audit(2020-03-17 11:35:31.474:344) : arch=x86_64 syscall=setsockopt success=yes exit=0 a0=0x7 a1=SOL_NETLINK a2=0x2 a3=0x7ffee21ca5f0 items=0 ppid=686 pid=689 auid=root uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=ttyS0 ses=3 comm=perl exe=/usr/bin/perl subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 key=(null)
type=UNKNOWN[1335] msg=audit(2020-03-17 11:35:31.474:344) : pid=689 uid=root auid=root tty=ttyS0 ses=3 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 comm=perl exe=/usr/bin/perl nl-mcgrp=1 op=disconnect res=yes
type=UNKNOWN[1335] msg=audit(2020-01-17 10:36:24.051:295) : pid=674 uid=root auid=root tty=ttyS0 ses=3 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 comm=perl exe=/usr/bin/perl nl-mcgrp=1 op=disconnect res=yes
Please see the upstream issue tracker at
https://github.com/linux-audit/audit-kernel/issues/28
With the feature description at
https://github.com/linux-audit/audit-kernel/wiki/RFE-Audit-Multicast-Sock...
The testsuite support is at
https://github.com/rgbriggs/audit-testsuite/compare/ghak28-mcast-part-join
https://github.com/linux-audit/audit-testsuite/pull/93
And the userspace support patch is at
https://github.com/linux-audit/audit-userspace/pull/114
Signed-off-by: Richard Guy Briggs <rgb(a)redhat.com>
---
Note: subj attrs included due to missing syscall record for disconnect on close
Note: tried refactor of subj attrs, but this is yet another new order.
Changelog:
v7:
- rename audit_log_multicast_bind to audit_log_multicast
v6:
- rebased on 5.6-rc1 audit/next and audit log BPF
- updated patch description sample records
v5:
- rebased on 5.5-rc1 audit/next
- group bind/unbind ops
- add audit context
- justify message number skip
- check audit_enabled
- change field name from nlnk-grp to nl-mcgrp
- fix whitespace issues
v4:
- 2017-10-13 sgrubb
- squash to 1 patch
- rebase on KERN_MODULE event
- open code subj attrs
v3:
- 2016-11-30 sgrubb
- rebase on REPLACE event
- minimize audit_log_format calls
- rename audit_log_bind to audit_log_multicast_bind
v2:
- 2015-07-23 sgrubb
- spin off audit_log_task_simple in seperate patch
v1:
- 2014-10-07 rgb
---
include/uapi/linux/audit.h | 1 +
kernel/audit.c | 48 ++++++++++++++++++++++++++++++++++++++++++----
2 files changed, 45 insertions(+), 4 deletions(-)
diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index a534d71e689a..9b6a973f4cc3 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -117,6 +117,7 @@
#define AUDIT_TIME_INJOFFSET 1332 /* Timekeeping offset injected */
#define AUDIT_TIME_ADJNTPVAL 1333 /* NTP value adjustment */
#define AUDIT_BPF 1334 /* BPF subsystem */
+#define AUDIT_EVENT_LISTENER 1335 /* Task joined multicast read socket */
#define AUDIT_AVC 1400 /* SE Linux avc denial or grant */
#define AUDIT_SELINUX_ERR 1401 /* Internal SE Linux Errors */
diff --git a/kernel/audit.c b/kernel/audit.c
index b96331e1976d..612bd818f6d7 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1520,20 +1520,60 @@ static void audit_receive(struct sk_buff *skb)
audit_ctl_unlock();
}
+/* Log information about who is connecting to the audit multicast socket */
+static void audit_log_multicast(int group, const char *op, int err)
+{
+ const struct cred *cred;
+ struct tty_struct *tty;
+ char comm[sizeof(current->comm)];
+ struct audit_buffer *ab;
+
+ if (!audit_enabled)
+ return;
+
+ ab = audit_log_start(audit_context(), GFP_KERNEL, AUDIT_EVENT_LISTENER);
+ if (!ab)
+ return;
+
+ cred = current_cred();
+ tty = audit_get_tty();
+ audit_log_format(ab, "pid=%u uid=%u auid=%u tty=%s ses=%u",
+ task_pid_nr(current),
+ from_kuid(&init_user_ns, cred->uid),
+ from_kuid(&init_user_ns, audit_get_loginuid(current)),
+ tty ? tty_name(tty) : "(none)",
+ audit_get_sessionid(current));
+ audit_put_tty(tty);
+ audit_log_task_context(ab); /* subj= */
+ audit_log_format(ab, " comm=");
+ audit_log_untrustedstring(ab, get_task_comm(comm, current));
+ audit_log_d_path_exe(ab, current->mm); /* exe= */
+ audit_log_format(ab, " nl-mcgrp=%d op=%s res=%d", group, op, !err);
+ audit_log_end(ab);
+}
+
/* Run custom bind function on netlink socket group connect or bind requests. */
-static int audit_bind(struct net *net, int group)
+static int audit_multicast_bind(struct net *net, int group)
{
+ int err = 0;
+
if (!capable(CAP_AUDIT_READ))
- return -EPERM;
+ err = -EPERM;
+ audit_log_multicast(group, "connect", err);
+ return err;
+}
- return 0;
+static void audit_multicast_unbind(struct net *net, int group)
+{
+ audit_log_multicast(group, "disconnect", 0);
}
static int __net_init audit_net_init(struct net *net)
{
struct netlink_kernel_cfg cfg = {
.input = audit_receive,
- .bind = audit_bind,
+ .bind = audit_multicast_bind,
+ .unbind = audit_multicast_unbind,
.flags = NL_CFG_F_NONROOT_RECV,
.groups = AUDIT_NLGRP_MAX,
};
--
1.8.3.1
4 years
[PATCH ghak25 v3 0/3] Address NETFILTER_CFG issues
by Richard Guy Briggs
There were questions about the presence and cause of unsolicited syscall events
in the logs containing NETFILTER_CFG records and sometimes unaccompanied
NETFILTER_CFG records.
During testing at least the following list of events trigger NETFILTER_CFG
records and the syscalls related (There may be more events that will trigger
this message type.):
init_module, finit_module: modprobe
delete_module: rmmod
setsockopt: iptables-restore, ip6tables-restore, ebtables-restore
unshare: (h?)ostnamed, updatedb
clone: libvirtd
kernel threads garbage collecting empty ebtables
The syscall events unsolicited by any audit rule were found to be caused by a
missing !audit_dummy_context() check before issuing a NETFILTER_CFG
record. In fact, since this is a configuration change it is required,
and we always want the accompanying syscall record even with no rules
present, so this has been addressed by ghak120.
The vast majority of unaccompanied records are caused by the fedora default
rule: "-a never,task" and the occasional early startup one is I believe caused
by the iptables filter table module hard linked into the kernel rather than a
loadable module.
A couple of other factors should help eliminate unaccompanied records
which include commit cb74ed278f80 ("audit: always enable syscall
auditing when supported and audit is enabled") which makes sure that
when audit is enabled, so automatically is syscall auditing, and ghak66
which addressed initializing audit before PID 1.
Ebtables module initialization to register tables doesn't generate records
because it was never hooked in to audit. Recommend adding audit hooks to log
this covered by ghak43 covered by patch 1.
Table unregistration was never logged, which is now covered by ghak44 in
patch 2. Unaccompanied records were caused by kernel threads
automatically unregistering empty ebtables, which necessitates adding
subject credentials covered in patch 3.
Seemingly duplicate records are not actually exact duplicates that are caused
by netfilter table initialization in different network namespaces from the same
syscall. Recommend adding the network namespace ID (proc inode and dev)
to the record to make this obvious (address later with ghak79 after nsid
patches).
See: https://github.com/linux-audit/audit-kernel/issues/25
See: https://github.com/linux-audit/audit-kernel/issues/35
See: https://github.com/linux-audit/audit-kernel/issues/43
See: https://github.com/linux-audit/audit-kernel/issues/44
Changelog:
v3
- rebase on v5.6-rc1 audit/next
- change audit_nf_cfg to audit_log_nfcfg
- squash 2,3,4,5 to 1 and update patch descriptions
- add subject credentials to cover garbage collecting kernel threads
v2
- Rebase (audit/next 5.5-rc1) to get audit_context access and ebt_register_table ret code
- Split x_tables and ebtables updates
- Check audit_dummy_context
- Store struct audit_nfcfg params in audit_context, abstract to audit_nf_cfg() call
- Restore back to "table, family, entries" from "family, table, entries"
- Log unregistration of tables
- Add "op=" at the end of the AUDIT_NETFILTER_CFG record
- Defer nsid patch (ghak79) to once nsid patchset upstreamed (ghak32)
- Add ghak refs
- Ditch NETFILTER_CFGSOLO record
Richard Guy Briggs (3):
audit: tidy and extend netfilter_cfg x_tables and ebtables logging
netfilter: add audit table unregister actions
audit: add subj creds to NETFILTER_CFG record to cover async
unregister
include/linux/audit.h | 20 +++++++++++++++++++
kernel/auditsc.c | 43 +++++++++++++++++++++++++++++++++++++++++
net/bridge/netfilter/ebtables.c | 14 ++++++--------
net/netfilter/x_tables.c | 14 +++++---------
4 files changed, 74 insertions(+), 17 deletions(-)
--
1.8.3.1
4 years
Re: [PATCH v2] kernel: audit.c: Add __rcu notation to RCU pointer
by Joel Fernandes
On Thu, Nov 28, 2019 at 09:02:03PM +0530, Amol Grover wrote:
> add __rcu notation to RCU protected global pointer auditd_conn
Again, please use proper punctuation and captilization. This is unacceptable.
Please put more effort into changelog.
Otherwise the patch diff itself looks good to me, with the above nit
corrected, you could add my tag to the next revision:
Reviewed-by: Joel Fernandes (Google) <joel(a)joelfernandes.org>
thanks,
- Joel
>
> Fixes multiple instances of sparse error:
> error: incompatible types in comparison expression
> (different address spaces)
>
> Signed-off-by: Amol Grover <frextrite(a)gmail.com>
> ---
> v2:
> - fix erroneous RCU pointer initialization
>
> kernel/audit.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/audit.c b/kernel/audit.c
> index da8dc0db5bd3..ff7cfc61f53d 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -102,12 +102,13 @@ struct audit_net {
> * This struct is RCU protected; you must either hold the RCU lock for reading
> * or the associated spinlock for writing.
> */
> -static struct auditd_connection {
> +struct auditd_connection {
> struct pid *pid;
> u32 portid;
> struct net *net;
> struct rcu_head rcu;
> -} *auditd_conn = NULL;
> +};
> +static struct auditd_connection __rcu *auditd_conn;
> static DEFINE_SPINLOCK(auditd_conn_lock);
>
> /* If audit_rate_limit is non-zero, limit the rate of sending audit records
> --
> 2.24.0
>
4 years, 1 month
[GIT PULL] Audit patches for v5.7
by Paul Moore
Hi Linus,
We've got two audit patches for the v5.7 merge window with a stellar
14 lines changed between the two patches. The patch descriptions are
far more lengthy than the patches themselves, which is a very good
thing for patches this size IMHO. The patches pass our test suites
and a quick summary is below, please merge for v5.7.
- Stop logging inode information when updating an audit file watch.
Since we are not changing the inode, or the fact that we are watching
the associated file, the inode information is just noise that we can
do without.
- Fix a problem where mandatory audit records were missing their
accompanying audit records (e.g. SYSCALL records were missing). The
missing records often meant that we didn't have the necessary context
to understand what was going on when the event occurred.
Thanks,
-Paul
--
The following changes since commit bb6d3fb354c5ee8d6bde2d576eb7220ea09862b9:
Linux 5.6-rc1 (2020-02-09 16:08:48 -0800)
are available in the Git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit.git
tags/audit-pr-20200330
for you to fetch changes up to 1320a4052ea11eb2879eb7361da15a106a780972:
audit: trigger accompanying records when no rules present
(2020-03-12 10:42:51-0400)
----------------------------------------------------------------
audit/stable-5.7 PR 20200330
----------------------------------------------------------------
Richard Guy Briggs (1):
audit: trigger accompanying records when no rules present
Steve Grubb (1):
audit: CONFIG_CHANGE don't log internal bookkeeping as an event
kernel/audit.c | 1 +
kernel/audit.h | 8 ++++++++
kernel/audit_watch.c | 2 --
kernel/auditsc.c | 3 ---
4 files changed, 9 insertions(+), 5 deletions(-)
--
paul moore
www.paul-moore.com
4 years, 1 month
Audit record ordering requirements
by Casey Schaufler
I'm looking at adding an audit record type for the case where
there are multiple security modules providing subject data. There
are several reasons to create a new record rather than adding the
additional information to existing records, including possible
size overflows and format compatibility.
While working with the code I have found that it is much easier
if the new record (I'm calling it MAC_TASK_CONTEXTS) can be generated
before the "base" record, which could be a SYSCALL record, than
after it. Can I get away with this? I haven't seen any documentation
that says the CWD record has to follow the event's SYSCALL record,
but I wouldn't be at all surprised if it's implicitly assumed.
Thanks.
4 years, 1 month
Full shell access or sudo command
by MAUPERTUIS, PHILIPPE
Hi,
Our sysadmins are able to use sudo to take a root shell and do whatever they want.
On the contrary, application managers for example have only a limited set of sudo scripts and commands
Is it possible to find if a given audit message (for example due to a watch on a file) has been issued in the context of sudo or a shell?
My goal is to be able to search for potential sudo abuse through misconfiguration.
Philippe
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4 years, 1 month
Re: Looking for help testing patch attestation
by Konstantin Ryabitsev
On Tue, Mar 17, 2020 at 06:51:38PM -0400, Paul Moore wrote:
> You might want to extend this test to the LSM list as well. I'm
> refraining from CC'ing them on this email because I don't want to
> spoil your beta test rollout, but I think it would be a good thing to
> do.
I'll do that, thanks! I'll also loop in kernel-hardening folks.
> Speaking as the person who merges patches for both the SELinux and
> audit kernel subsystems, I look at every patch I merge; I don't
> blindly merge patches (even from certain "trusted" individuals).
> Simply put, I've always considered that to be part of the job. While
> the patch attestation could provide some assurance about who created
> the patch (assuming a reasonable web-of-trust), and that it hadn't
> been tampered with, I feel it is more important to review correctness
> than it is to guarantee provenance. If you ever develop a tool which
> can help with the correctness part, I'll gladly jump to the front of
> the line to test that one! ;)
Yes I understand -- I view this as an auxiliary feature that helps
maintainers in their duties, but certainly doesn't aim to replace due
diligence. I am most worried about the following scenario:
1. a maintainer receives a long series of patches that arrives into
their inbox
2. they carefully review the patches and decide to merge them
3. they use "b4 am" to grab that patch series from lore.kernel.org
4. however, the archive has been manipulated and returns patches
containing malicious edits, which get merged because the maintainer
assumes that what "b4 am" returns is the same as what they reviewed
Cryptographic attestations helps hedge against this scenario by removing
any implicit trust from the centralized system like lore.kernel.org (or
patchwork.kernel.org, for that matter).
> Having said that, I'm happy to see work going into tools like this,
> and at some point I'll look into adding it into my workflow for an
> extra level of safety (although I'm on the fence about making it
> mandatory for submissions). Sorry to disappoint, but I'm probably not
> the best test monkey right now.
All good, this is why I'm casting the net wide looking for initial
adopters. :)
Best regards,
Konstantin
4 years, 2 months
Re: Looking for help testing patch attestation
by Paul Moore
[NOTE: fixed with the proper linux-audit address]
On Tue, Mar 17, 2020 at 6:51 PM Paul Moore <paul(a)paul-moore.com> wrote:
> On Tue, Mar 17, 2020 at 6:12 PM Konstantin Ryabitsev
> <konstantin(a)linuxfoundation.org> wrote:
> > Hello, all:
> >
> > I'm reaching out to you because you're a security-oriented mailing list
> > and would likely be among the folks most interested in end-to-end
> > cryptographic patch attestation features -- or, at least, you're likely
> > to be least indifferent about it. :)
> >
> > In brief:
> >
> > - the mechanism I propose uses an external mailing list for attestation
> > data, so list subscribers will see no changes to the mailing list
> > traffic at all (no proliferation of pgp signatures, extra junky
> > messages, etc)
> > - attestation can be submitted after the fact for patches/series that
> > were already sent to the list, so a maintainer can ask for attestation
> > to be provided post-fact before they apply the series to their git
> > tree
> > - a single attestation document is generated per series (or, in fact,
> > any collection of patches)
> >
> > For technical details of the proposed scheme, please see the following
> > LWN article:
> > https://lwn.net/Articles/813646/
> >
> > The proposal is still experimental and requires more real-life testing
> > before I feel comfortable inviting wider participation. This is why I am
> > approaching individual lists that are likely to show interest in this
> > idea.
> >
> > If you are interested in participating, all you need to do is to install
> > the "b4" tool and start submitting and checking patch attestation.
> > Please see the following post for details:
> >
> > https://people.kernel.org/monsieuricon/introducing-b4-and-patch-attestation
> >
> > With any feedback, please email the tools(a)linux.kernel.org list in order
> > to minimize off-topic conversations on this list.
>
> Hi Konstantin,
>
> You might want to extend this test to the LSM list as well. I'm
> refraining from CC'ing them on this email because I don't want to
> spoil your beta test rollout, but I think it would be a good thing to
> do.
>
> Speaking as the person who merges patches for both the SELinux and
> audit kernel subsystems, I look at every patch I merge; I don't
> blindly merge patches (even from certain "trusted" individuals).
> Simply put, I've always considered that to be part of the job. While
> the patch attestation could provide some assurance about who created
> the patch (assuming a reasonable web-of-trust), and that it hadn't
> been tampered with, I feel it is more important to review correctness
> than it is to guarantee provenance. If you ever develop a tool which
> can help with the correctness part, I'll gladly jump to the front of
> the line to test that one! ;)
>
> Having said that, I'm happy to see work going into tools like this,
> and at some point I'll look into adding it into my workflow for an
> extra level of safety (although I'm on the fence about making it
> mandatory for submissions). Sorry to disappoint, but I'm probably not
> the best test monkey right now.
>
> --
> paul moore
> www.paul-moore.com
--
paul moore
www.paul-moore.com
4 years, 2 months
