| Message ID | 2e5d93ee46feca915a101c2fc3062da674a98223.1519930146.git.rgb@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 2018-03-01 14:41, Richard Guy Briggs wrote: > Implement the proc fs write to set the audit container ID of a process, > emitting an AUDIT_CONTAINER record to document the event. > > This is a write from the container orchestrator task to a proc entry of > the form /proc/PID/containerid where PID is the process ID of the newly > created task that is to become the first task in a container, or an > additional task added to a container. > > The write expects up to a u64 value (unset: 18446744073709551615). > > This will produce a record such as this: > type=UNKNOWN[1333] msg=audit(1519903238.968:261): op=set pid=596 uid=0 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 auid=0 tty=pts0 ses=1 opid=596 old-contid=18446744073709551615 contid=123455 res=0 > > The "op" field indicates an initial set. The "pid" to "ses" fields are > the orchestrator while the "opid" field is the object's PID, the process > being "contained". Old and new container ID values are given in the > "contid" fields, while res indicates its success. > > It is not permitted to self-set, unset or re-set the container ID. A > child inherits its parent's container ID, but then can be set only once > after. There are more restrictions coming later: - check that the child being set has no children or threads yet, or forcibly set them all to the same container ID (assuming they all pass the same tests). This will also prevent an orch from setting its parent and other tit-for-tat games to circumvent the basic checks. > See: https://github.com/linux-audit/audit-kernel/issues/32 > > Signed-off-by: Richard Guy Briggs <rgb@redhat.com> > --- > fs/proc/base.c | 37 ++++++++++++++++++++ > include/linux/audit.h | 16 +++++++++ > include/linux/init_task.h | 4 ++- > include/linux/sched.h | 1 + > include/uapi/linux/audit.h | 2 ++ > kernel/auditsc.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++ > 6 files changed, 145 insertions(+), 1 deletion(-) > > diff --git a/fs/proc/base.c b/fs/proc/base.c > index 60316b5..6ce4fbe 100644 > --- a/fs/proc/base.c > +++ b/fs/proc/base.c > @@ -1299,6 +1299,41 @@ static ssize_t proc_sessionid_read(struct file * file, char __user * buf, > .read = proc_sessionid_read, > .llseek = generic_file_llseek, > }; > + > +static ssize_t proc_containerid_write(struct file *file, const char __user *buf, > + size_t count, loff_t *ppos) > +{ > + struct inode *inode = file_inode(file); > + u64 containerid; > + int rv; > + struct task_struct *task = get_proc_task(inode); > + > + if (!task) > + return -ESRCH; > + if (*ppos != 0) { > + /* No partial writes. */ > + put_task_struct(task); > + return -EINVAL; > + } > + > + rv = kstrtou64_from_user(buf, count, 10, &containerid); > + if (rv < 0) { > + put_task_struct(task); > + return rv; > + } > + > + rv = audit_set_containerid(task, containerid); > + put_task_struct(task); > + if (rv < 0) > + return rv; > + return count; > +} > + > +static const struct file_operations proc_containerid_operations = { > + .write = proc_containerid_write, > + .llseek = generic_file_llseek, > +}; > + > #endif > > #ifdef CONFIG_FAULT_INJECTION > @@ -2961,6 +2996,7 @@ static int proc_pid_patch_state(struct seq_file *m, struct pid_namespace *ns, > #ifdef CONFIG_AUDITSYSCALL > REG("loginuid", S_IWUSR|S_IRUGO, proc_loginuid_operations), > REG("sessionid", S_IRUGO, proc_sessionid_operations), > + REG("containerid", S_IWUSR, proc_containerid_operations), > #endif > #ifdef CONFIG_FAULT_INJECTION > REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations), > @@ -3355,6 +3391,7 @@ static int proc_tid_comm_permission(struct inode *inode, int mask) > #ifdef CONFIG_AUDITSYSCALL > REG("loginuid", S_IWUSR|S_IRUGO, proc_loginuid_operations), > REG("sessionid", S_IRUGO, proc_sessionid_operations), > + REG("containerid", S_IWUSR, proc_containerid_operations), > #endif > #ifdef CONFIG_FAULT_INJECTION > REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations), > diff --git a/include/linux/audit.h b/include/linux/audit.h > index af410d9..fe4ba3f 100644 > --- a/include/linux/audit.h > +++ b/include/linux/audit.h > @@ -29,6 +29,7 @@ > > #define AUDIT_INO_UNSET ((unsigned long)-1) > #define AUDIT_DEV_UNSET ((dev_t)-1) > +#define INVALID_CID AUDIT_CID_UNSET > > struct audit_sig_info { > uid_t uid; > @@ -321,6 +322,7 @@ static inline void audit_ptrace(struct task_struct *t) > extern int auditsc_get_stamp(struct audit_context *ctx, > struct timespec64 *t, unsigned int *serial); > extern int audit_set_loginuid(kuid_t loginuid); > +extern int audit_set_containerid(struct task_struct *tsk, u64 containerid); > > static inline kuid_t audit_get_loginuid(struct task_struct *tsk) > { > @@ -332,6 +334,11 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk) > return tsk->sessionid; > } > > +static inline u64 audit_get_containerid(struct task_struct *tsk) > +{ > + return tsk->containerid; > +} > + > extern void __audit_ipc_obj(struct kern_ipc_perm *ipcp); > extern void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, umode_t mode); > extern void __audit_bprm(struct linux_binprm *bprm); > @@ -517,6 +524,10 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk) > { > return -1; > } > +static inline kuid_t audit_get_containerid(struct task_struct *tsk) > +{ > + return INVALID_CID; > +} > static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp) > { } > static inline void audit_ipc_set_perm(unsigned long qbytes, uid_t uid, > @@ -581,6 +592,11 @@ static inline bool audit_loginuid_set(struct task_struct *tsk) > return uid_valid(audit_get_loginuid(tsk)); > } > > +static inline bool audit_containerid_set(struct task_struct *tsk) > +{ > + return audit_get_containerid(tsk) != INVALID_CID; > +} > + > static inline void audit_log_string(struct audit_buffer *ab, const char *buf) > { > audit_log_n_string(ab, buf, strlen(buf)); > diff --git a/include/linux/init_task.h b/include/linux/init_task.h > index 6a53262..046bd0a 100644 > --- a/include/linux/init_task.h > +++ b/include/linux/init_task.h > @@ -18,6 +18,7 @@ > #include <linux/sched/rt.h> > #include <linux/livepatch.h> > #include <linux/mm_types.h> > +#include <linux/audit.h> > > #include <asm/thread_info.h> > > @@ -120,7 +121,8 @@ > #ifdef CONFIG_AUDITSYSCALL > #define INIT_IDS \ > .loginuid = INVALID_UID, \ > - .sessionid = (unsigned int)-1, > + .sessionid = (unsigned int)-1, \ > + .containerid = INVALID_CID, > #else > #define INIT_IDS > #endif > diff --git a/include/linux/sched.h b/include/linux/sched.h > index d258826..1b82191 100644 > --- a/include/linux/sched.h > +++ b/include/linux/sched.h > @@ -796,6 +796,7 @@ struct task_struct { > #ifdef CONFIG_AUDITSYSCALL > kuid_t loginuid; > unsigned int sessionid; > + u64 containerid; > #endif > struct seccomp seccomp; > > diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h > index 4e61a9e..921a71f 100644 > --- a/include/uapi/linux/audit.h > +++ b/include/uapi/linux/audit.h > @@ -71,6 +71,7 @@ > #define AUDIT_TTY_SET 1017 /* Set TTY auditing status */ > #define AUDIT_SET_FEATURE 1018 /* Turn an audit feature on or off */ > #define AUDIT_GET_FEATURE 1019 /* Get which features are enabled */ > +#define AUDIT_CONTAINER 1020 /* Define the container id and information */ > > #define AUDIT_FIRST_USER_MSG 1100 /* Userspace messages mostly uninteresting to kernel */ > #define AUDIT_USER_AVC 1107 /* We filter this differently */ > @@ -465,6 +466,7 @@ struct audit_tty_status { > }; > > #define AUDIT_UID_UNSET (unsigned int)-1 > +#define AUDIT_CID_UNSET ((u64)-1) > > /* audit_rule_data supports filter rules with both integer and string > * fields. It corresponds with AUDIT_ADD_RULE, AUDIT_DEL_RULE and > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > index 4e0a4ac..0ee1e59 100644 > --- a/kernel/auditsc.c > +++ b/kernel/auditsc.c > @@ -2073,6 +2073,92 @@ int audit_set_loginuid(kuid_t loginuid) > return rc; > } > > +static int audit_set_containerid_perm(struct task_struct *task, u64 containerid) > +{ > + struct task_struct *parent; > + u64 pcontainerid, ccontainerid; > + pid_t ppid; > + > + /* Don't allow to set our own containerid */ > + if (current == task) > + return -EPERM; > + /* Don't allow the containerid to be unset */ > + if (!cid_valid(containerid)) > + return -EINVAL; > + /* if we don't have caps, reject */ > + if (!capable(CAP_AUDIT_CONTROL)) > + return -EPERM; > + /* if containerid is unset, allow */ > + if (!audit_containerid_set(task)) > + return 0; > + /* it is already set, and not inherited from the parent, reject */ > + ccontainerid = audit_get_containerid(task); > + rcu_read_lock(); > + parent = rcu_dereference(task->real_parent); > + rcu_read_unlock(); > + task_lock(parent); > + pcontainerid = audit_get_containerid(parent); > + ppid = task_tgid_nr(parent); > + task_unlock(parent); > + if (ccontainerid != pcontainerid) > + return -EPERM; > + return 0; > +} > + > +static void audit_log_set_containerid(struct task_struct *task, u64 oldcontainerid, > + u64 containerid, int rc) > +{ > + struct audit_buffer *ab; > + uid_t uid; > + struct tty_struct *tty; > + > + if (!audit_enabled) > + return; > + > + ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONTAINER); > + if (!ab) > + return; > + > + uid = from_kuid(&init_user_ns, task_uid(current)); > + tty = audit_get_tty(current); > + > + audit_log_format(ab, "op=set pid=%d uid=%u", task_tgid_nr(current), uid); > + audit_log_task_context(ab); > + audit_log_format(ab, " auid=%u tty=%s ses=%u opid=%d old-contid=%llu contid=%llu res=%d", > + from_kuid(&init_user_ns, audit_get_loginuid(current)), > + tty ? tty_name(tty) : "(none)", audit_get_sessionid(current), > + task_tgid_nr(task), oldcontainerid, containerid, !rc); > + > + audit_put_tty(tty); > + audit_log_end(ab); > +} > + > +/** > + * audit_set_containerid - set current task's audit_context containerid > + * @containerid: containerid value > + * > + * Returns 0 on success, -EPERM on permission failure. > + * > + * Called (set) from fs/proc/base.c::proc_containerid_write(). > + */ > +int audit_set_containerid(struct task_struct *task, u64 containerid) > +{ > + u64 oldcontainerid; > + int rc; > + > + oldcontainerid = audit_get_containerid(task); > + > + rc = audit_set_containerid_perm(task, containerid); > + if (!rc) { > + task_lock(task); > + task->containerid = containerid; > + task_unlock(task); > + } > + > + audit_log_set_containerid(task, oldcontainerid, containerid, rc); > + return rc; > +} > + > /** > * __audit_mq_open - record audit data for a POSIX MQ open > * @oflag: open flag > -- > 1.8.3.1 > - RGB -- Richard Guy Briggs <rgb@redhat.com> Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635
On Thu, Mar 1, 2018 at 8:41 PM, Richard Guy Briggs <rgb@redhat.com> wrote: > On 2018-03-01 14:41, Richard Guy Briggs wrote: >> Implement the proc fs write to set the audit container ID of a process, >> emitting an AUDIT_CONTAINER record to document the event. >> >> This is a write from the container orchestrator task to a proc entry of >> the form /proc/PID/containerid where PID is the process ID of the newly >> created task that is to become the first task in a container, or an >> additional task added to a container. >> >> The write expects up to a u64 value (unset: 18446744073709551615). >> >> This will produce a record such as this: >> type=UNKNOWN[1333] msg=audit(1519903238.968:261): op=set pid=596 uid=0 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 auid=0 tty=pts0 ses=1 opid=596 old-contid=18446744073709551615 contid=123455 res=0 >> >> The "op" field indicates an initial set. The "pid" to "ses" fields are >> the orchestrator while the "opid" field is the object's PID, the process >> being "contained". Old and new container ID values are given in the >> "contid" fields, while res indicates its success. >> >> It is not permitted to self-set, unset or re-set the container ID. A >> child inherits its parent's container ID, but then can be set only once >> after. > > There are more restrictions coming later: > - check that the child being set has no children or threads yet, or > forcibly set them all to the same container ID (assuming they all pass > the same tests). This will also prevent an orch from setting its > parent and other tit-for-tat games to circumvent the basic checks. FYI, I think you may have a problem with something in your outgoing mail path; I didn't receive the original patchset you are referencing and it doesn't appear in the mail archive either.
On Fri, Mar 02, 2018 at 10:48:42AM -0500, Paul Moore wrote: > On Thu, Mar 1, 2018 at 8:41 PM, Richard Guy Briggs <rgb@redhat.com> wrote: > > On 2018-03-01 14:41, Richard Guy Briggs wrote: > FYI, I think you may have a problem with something in your outgoing > mail path; I didn't receive the original patchset you are referencing > and it doesn't appear in the mail archive either. I have those patches. Which mail archive is missing them?
On Fri, Mar 2, 2018 at 1:23 PM, Matthew Wilcox <willy@infradead.org> wrote: > On Fri, Mar 02, 2018 at 10:48:42AM -0500, Paul Moore wrote: >> On Thu, Mar 1, 2018 at 8:41 PM, Richard Guy Briggs <rgb@redhat.com> wrote: >> > On 2018-03-01 14:41, Richard Guy Briggs wrote: >> FYI, I think you may have a problem with something in your outgoing >> mail path; I didn't receive the original patchset you are referencing >> and it doesn't appear in the mail archive either. > > I have those patches. Which mail archive is missing them? The archive run by the linux-audit mailing list: * https://www.redhat.com/archives/linux-audit
On Fri, Mar 2, 2018 at 2:25 PM, Paul Moore <paul@paul-moore.com> wrote: > On Fri, Mar 2, 2018 at 1:23 PM, Matthew Wilcox <willy@infradead.org> wrote: >> On Fri, Mar 02, 2018 at 10:48:42AM -0500, Paul Moore wrote: >>> On Thu, Mar 1, 2018 at 8:41 PM, Richard Guy Briggs <rgb@redhat.com> wrote: >>> > On 2018-03-01 14:41, Richard Guy Briggs wrote: >>> FYI, I think you may have a problem with something in your outgoing >>> mail path; I didn't receive the original patchset you are referencing >>> and it doesn't appear in the mail archive either. >> >> I have those patches. Which mail archive is missing them? > > The archive run by the linux-audit mailing list: > > * https://www.redhat.com/archives/linux-audit After having my reply get bounced from the linux-audit list I realized that Richard had gotten a little overzealous with the number of recipients (note to Richard, you easily could have dropped some of those lists/people from the To/CC line). I was able to get in and free those patches from the moderation queue, they should be arriving on the linux-audit list shortly.
On Thu, Mar 01, 2018 at 02:41:04PM -0500, Richard Guy Briggs wrote: ... > +static inline bool audit_containerid_set(struct task_struct *tsk) Hi Richard, the calls to audit_containerid_set() confused me. Could you make it is_audit_containerid_set() or audit_containerid_isset()? > +{ > + return audit_get_containerid(tsk) != INVALID_CID; > +}
On Sat, Mar 3, 2018 at 4:19 AM, Serge E. Hallyn <serge@hallyn.com> wrote: > On Thu, Mar 01, 2018 at 02:41:04PM -0500, Richard Guy Briggs wrote: > ... >> +static inline bool audit_containerid_set(struct task_struct *tsk) > > Hi Richard, > > the calls to audit_containerid_set() confused me. Could you make it > is_audit_containerid_set() or audit_containerid_isset()? I haven't gone through the entire patchset yet, but I wanted to quickly comment on this ... I really dislike the function-names-as-sentences approach and would would greatly prefer audit_containerid_isset(). >> +{ >> + return audit_get_containerid(tsk) != INVALID_CID; >> +}
On 2018-03-04 10:01, Paul Moore wrote: > On Sat, Mar 3, 2018 at 4:19 AM, Serge E. Hallyn <serge@hallyn.com> wrote: > > On Thu, Mar 01, 2018 at 02:41:04PM -0500, Richard Guy Briggs wrote: > > ... > >> +static inline bool audit_containerid_set(struct task_struct *tsk) > > > > Hi Richard, > > > > the calls to audit_containerid_set() confused me. Could you make it > > is_audit_containerid_set() or audit_containerid_isset()? > > I haven't gone through the entire patchset yet, but I wanted to > quickly comment on this ... I really dislike the > function-names-as-sentences approach and would would greatly prefer > audit_containerid_isset(). I'd be ok with this latter if necessary, but the naming mimics the existing loginuid naming convention. > >> +{ > >> + return audit_get_containerid(tsk) != INVALID_CID; > >> +} > > paul moore - RGB -- Richard Guy Briggs <rgb@redhat.com> Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635
On 03/01/2018 02:41 PM, Richard Guy Briggs wrote: > Implement the proc fs write to set the audit container ID of a process, > emitting an AUDIT_CONTAINER record to document the event. > > This is a write from the container orchestrator task to a proc entry of > the form /proc/PID/containerid where PID is the process ID of the newly > created task that is to become the first task in a container, or an > additional task added to a container. > > The write expects up to a u64 value (unset: 18446744073709551615). > > This will produce a record such as this: > type=UNKNOWN[1333] msg=audit(1519903238.968:261): op=set pid=596 uid=0 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 auid=0 tty=pts0 ses=1 opid=596 old-contid=18446744073709551615 contid=123455 res=0 > > The "op" field indicates an initial set. The "pid" to "ses" fields are > the orchestrator while the "opid" field is the object's PID, the process > being "contained". Old and new container ID values are given in the > "contid" fields, while res indicates its success. > > It is not permitted to self-set, unset or re-set the container ID. A > child inherits its parent's container ID, but then can be set only once > after. > > See: https://github.com/linux-audit/audit-kernel/issues/32 > > > /* audit_rule_data supports filter rules with both integer and string > * fields. It corresponds with AUDIT_ADD_RULE, AUDIT_DEL_RULE and > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > index 4e0a4ac..0ee1e59 100644 > --- a/kernel/auditsc.c > +++ b/kernel/auditsc.c > @@ -2073,6 +2073,92 @@ int audit_set_loginuid(kuid_t loginuid) > return rc; > } > > +static int audit_set_containerid_perm(struct task_struct *task, u64 containerid) > +{ > + struct task_struct *parent; > + u64 pcontainerid, ccontainerid; > + pid_t ppid; > + > + /* Don't allow to set our own containerid */ > + if (current == task) > + return -EPERM; > + /* Don't allow the containerid to be unset */ > + if (!cid_valid(containerid)) > + return -EINVAL; > + /* if we don't have caps, reject */ > + if (!capable(CAP_AUDIT_CONTROL)) > + return -EPERM; > + /* if containerid is unset, allow */ > + if (!audit_containerid_set(task)) > + return 0; I am wondering whether there should be a check for the target process that will receive the containerid to not have CAP_SYS_ADMIN that would otherwise allow it to arbitrarily unshare()/clone() and leave the set of namespaces that may make up the container whose containerid we assign here? > + /* it is already set, and not inherited from the parent, reject */ > + ccontainerid = audit_get_containerid(task); > + rcu_read_lock(); > + parent = rcu_dereference(task->real_parent); > + rcu_read_unlock(); > + task_lock(parent); > + pcontainerid = audit_get_containerid(parent); > + ppid = task_tgid_nr(parent); ppid not needed... > + task_unlock(parent); > + if (ccontainerid != pcontainerid) > + return -EPERM; > + return 0; > +} > + > +static void audit_log_set_containerid(struct task_struct *task, u64 oldcontainerid, > + u64 containerid, int rc) > +{ > + struct audit_buffer *ab; > + uid_t uid; > + struct tty_struct *tty; > + > + if (!audit_enabled) > + return; > + > + ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONTAINER); > + if (!ab) > + return; > + > + uid = from_kuid(&init_user_ns, task_uid(current)); > + tty = audit_get_tty(current); > + > + audit_log_format(ab, "op=set pid=%d uid=%u", task_tgid_nr(current), uid); > + audit_log_task_context(ab); > + audit_log_format(ab, " auid=%u tty=%s ses=%u opid=%d old-contid=%llu contid=%llu res=%d", > + from_kuid(&init_user_ns, audit_get_loginuid(current)), > + tty ? tty_name(tty) : "(none)", audit_get_sessionid(current), > + task_tgid_nr(task), oldcontainerid, containerid, !rc); > + > + audit_put_tty(tty); > + audit_log_end(ab); > +} > + > +/** > + * audit_set_containerid - set current task's audit_context containerid > + * @containerid: containerid value > + * > + * Returns 0 on success, -EPERM on permission failure. > + * > + * Called (set) from fs/proc/base.c::proc_containerid_write(). > + */ > +int audit_set_containerid(struct task_struct *task, u64 containerid) > +{ > + u64 oldcontainerid; > + int rc; > + > + oldcontainerid = audit_get_containerid(task); > + > + rc = audit_set_containerid_perm(task, containerid); > + if (!rc) { > + task_lock(task); > + task->containerid = containerid; > + task_unlock(task); > + } > + > + audit_log_set_containerid(task, oldcontainerid, containerid, rc); > + return rc; > +} > + > /** > * __audit_mq_open - record audit data for a POSIX MQ open > * @oflag: open flag
On 2018-03-15 16:27, Stefan Berger wrote: > On 03/01/2018 02:41 PM, Richard Guy Briggs wrote: > > Implement the proc fs write to set the audit container ID of a process, > > emitting an AUDIT_CONTAINER record to document the event. > > > > This is a write from the container orchestrator task to a proc entry of > > the form /proc/PID/containerid where PID is the process ID of the newly > > created task that is to become the first task in a container, or an > > additional task added to a container. > > > > The write expects up to a u64 value (unset: 18446744073709551615). > > > > This will produce a record such as this: > > type=UNKNOWN[1333] msg=audit(1519903238.968:261): op=set pid=596 uid=0 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 auid=0 tty=pts0 ses=1 opid=596 old-contid=18446744073709551615 contid=123455 res=0 > > > > The "op" field indicates an initial set. The "pid" to "ses" fields are > > the orchestrator while the "opid" field is the object's PID, the process > > being "contained". Old and new container ID values are given in the > > "contid" fields, while res indicates its success. > > > > It is not permitted to self-set, unset or re-set the container ID. A > > child inherits its parent's container ID, but then can be set only once > > after. > > > > See: https://github.com/linux-audit/audit-kernel/issues/32 > > > > > > /* audit_rule_data supports filter rules with both integer and string > > * fields. It corresponds with AUDIT_ADD_RULE, AUDIT_DEL_RULE and > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > > index 4e0a4ac..0ee1e59 100644 > > --- a/kernel/auditsc.c > > +++ b/kernel/auditsc.c > > @@ -2073,6 +2073,92 @@ int audit_set_loginuid(kuid_t loginuid) > > return rc; > > } > > > > +static int audit_set_containerid_perm(struct task_struct *task, u64 containerid) > > +{ > > + struct task_struct *parent; > > + u64 pcontainerid, ccontainerid; > > + pid_t ppid; > > + > > + /* Don't allow to set our own containerid */ > > + if (current == task) > > + return -EPERM; > > + /* Don't allow the containerid to be unset */ > > + if (!cid_valid(containerid)) > > + return -EINVAL; > > + /* if we don't have caps, reject */ > > + if (!capable(CAP_AUDIT_CONTROL)) > > + return -EPERM; > > + /* if containerid is unset, allow */ > > + if (!audit_containerid_set(task)) > > + return 0; > > I am wondering whether there should be a check for the target process that > will receive the containerid to not have CAP_SYS_ADMIN that would otherwise > allow it to arbitrarily unshare()/clone() and leave the set of namespaces > that may make up the container whose containerid we assign here? This is a reasonable question. This has been debated and I understood the conclusion was that without a clear definition of a "container", the task still remains in that container that just now has more sub-namespaces (in the case of hierarchical namespaces), we don't want to restrict it in such a way and that allows it to create nested containers. I see setns being more problematic if it could switch to another existing namespace that was set up by the orchestrator for a different container. The coming v2 patchset acknowledges this situation with the network namespace being potentially shared by multiple containers. This is the motivation for the code below that allows to set the containerid even if it is already inherited from its parent. > > + /* it is already set, and not inherited from the parent, reject */ > > + ccontainerid = audit_get_containerid(task); > > + rcu_read_lock(); > > + parent = rcu_dereference(task->real_parent); > > + rcu_read_unlock(); > > + task_lock(parent); > > + pcontainerid = audit_get_containerid(parent); > > + ppid = task_tgid_nr(parent); > > ppid not needed... Thanks for catching this. It was the vestige of a failed devel experiment that didn't flush that useless appendage. :-) > > + task_unlock(parent); > > + if (ccontainerid != pcontainerid) > > + return -EPERM; > > + return 0; > > +} > > + > > +static void audit_log_set_containerid(struct task_struct *task, u64 oldcontainerid, > > + u64 containerid, int rc) > > +{ > > + struct audit_buffer *ab; > > + uid_t uid; > > + struct tty_struct *tty; > > + > > + if (!audit_enabled) > > + return; > > + > > + ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONTAINER); > > + if (!ab) > > + return; > > + > > + uid = from_kuid(&init_user_ns, task_uid(current)); > > + tty = audit_get_tty(current); > > + > > + audit_log_format(ab, "op=set pid=%d uid=%u", task_tgid_nr(current), uid); > > + audit_log_task_context(ab); > > + audit_log_format(ab, " auid=%u tty=%s ses=%u opid=%d old-contid=%llu contid=%llu res=%d", > > + from_kuid(&init_user_ns, audit_get_loginuid(current)), > > + tty ? tty_name(tty) : "(none)", audit_get_sessionid(current), > > + task_tgid_nr(task), oldcontainerid, containerid, !rc); > > + > > + audit_put_tty(tty); > > + audit_log_end(ab); > > +} > > + > > +/** > > + * audit_set_containerid - set current task's audit_context containerid > > + * @containerid: containerid value > > + * > > + * Returns 0 on success, -EPERM on permission failure. > > + * > > + * Called (set) from fs/proc/base.c::proc_containerid_write(). > > + */ > > +int audit_set_containerid(struct task_struct *task, u64 containerid) > > +{ > > + u64 oldcontainerid; > > + int rc; > > + > > + oldcontainerid = audit_get_containerid(task); > > + > > + rc = audit_set_containerid_perm(task, containerid); > > + if (!rc) { > > + task_lock(task); > > + task->containerid = containerid; > > + task_unlock(task); > > + } > > + > > + audit_log_set_containerid(task, oldcontainerid, containerid, rc); > > + return rc; > > +} > > + > > /** > > * __audit_mq_open - record audit data for a POSIX MQ open > > * @oflag: open flag > > - RGB -- Richard Guy Briggs <rgb@redhat.com> Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635
On 03/15/2018 11:58 PM, Richard Guy Briggs wrote: > On 2018-03-15 16:27, Stefan Berger wrote: >> On 03/01/2018 02:41 PM, Richard Guy Briggs wrote: >>> Implement the proc fs write to set the audit container ID of a process, >>> emitting an AUDIT_CONTAINER record to document the event. >>> >>> This is a write from the container orchestrator task to a proc entry of >>> the form /proc/PID/containerid where PID is the process ID of the newly >>> created task that is to become the first task in a container, or an >>> additional task added to a container. >>> >>> The write expects up to a u64 value (unset: 18446744073709551615). >>> >>> This will produce a record such as this: >>> type=UNKNOWN[1333] msg=audit(1519903238.968:261): op=set pid=596 uid=0 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 auid=0 tty=pts0 ses=1 opid=596 old-contid=18446744073709551615 contid=123455 res=0 >>> >>> The "op" field indicates an initial set. The "pid" to "ses" fields are >>> the orchestrator while the "opid" field is the object's PID, the process >>> being "contained". Old and new container ID values are given in the >>> "contid" fields, while res indicates its success. >>> >>> It is not permitted to self-set, unset or re-set the container ID. A >>> child inherits its parent's container ID, but then can be set only once >>> after. >>> >>> See: https://github.com/linux-audit/audit-kernel/issues/32 >>> >>> >>> /* audit_rule_data supports filter rules with both integer and string >>> * fields. It corresponds with AUDIT_ADD_RULE, AUDIT_DEL_RULE and >>> diff --git a/kernel/auditsc.c b/kernel/auditsc.c >>> index 4e0a4ac..0ee1e59 100644 >>> --- a/kernel/auditsc.c >>> +++ b/kernel/auditsc.c >>> @@ -2073,6 +2073,92 @@ int audit_set_loginuid(kuid_t loginuid) >>> return rc; >>> } >>> >>> +static int audit_set_containerid_perm(struct task_struct *task, u64 containerid) >>> +{ >>> + struct task_struct *parent; >>> + u64 pcontainerid, ccontainerid; >>> + pid_t ppid; >>> + >>> + /* Don't allow to set our own containerid */ >>> + if (current == task) >>> + return -EPERM; >>> + /* Don't allow the containerid to be unset */ >>> + if (!cid_valid(containerid)) >>> + return -EINVAL; >>> + /* if we don't have caps, reject */ >>> + if (!capable(CAP_AUDIT_CONTROL)) >>> + return -EPERM; >>> + /* if containerid is unset, allow */ >>> + if (!audit_containerid_set(task)) >>> + return 0; >> I am wondering whether there should be a check for the target process that >> will receive the containerid to not have CAP_SYS_ADMIN that would otherwise >> allow it to arbitrarily unshare()/clone() and leave the set of namespaces >> that may make up the container whose containerid we assign here? > This is a reasonable question. This has been debated and I understood > the conclusion was that without a clear definition of a "container", the > task still remains in that container that just now has more > sub-namespaces (in the case of hierarchical namespaces), we don't want > to restrict it in such a way and that allows it to create nested > containers. I see setns being more problematic if it could switch to > another existing namespace that was set up by the orchestrator for a > different container. The coming v2 patchset acknowledges this situation > with the network namespace being potentially shared by multiple > containers. Are you going to post v2 soon? We would like to build on top of it for IMA namespacing and auditing inside of IMA namespaces. Stefan
On 2018-04-18 14:45, Stefan Berger wrote: > On 03/15/2018 11:58 PM, Richard Guy Briggs wrote: > > On 2018-03-15 16:27, Stefan Berger wrote: > > > On 03/01/2018 02:41 PM, Richard Guy Briggs wrote: > > > > Implement the proc fs write to set the audit container ID of a process, > > > > emitting an AUDIT_CONTAINER record to document the event. > > > > > > > > This is a write from the container orchestrator task to a proc entry of > > > > the form /proc/PID/containerid where PID is the process ID of the newly > > > > created task that is to become the first task in a container, or an > > > > additional task added to a container. > > > > > > > > The write expects up to a u64 value (unset: 18446744073709551615). > > > > > > > > This will produce a record such as this: > > > > type=UNKNOWN[1333] msg=audit(1519903238.968:261): op=set pid=596 uid=0 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 auid=0 tty=pts0 ses=1 opid=596 old-contid=18446744073709551615 contid=123455 res=0 > > > > > > > > The "op" field indicates an initial set. The "pid" to "ses" fields are > > > > the orchestrator while the "opid" field is the object's PID, the process > > > > being "contained". Old and new container ID values are given in the > > > > "contid" fields, while res indicates its success. > > > > > > > > It is not permitted to self-set, unset or re-set the container ID. A > > > > child inherits its parent's container ID, but then can be set only once > > > > after. > > > > > > > > See: https://github.com/linux-audit/audit-kernel/issues/32 > > > > > > > > > > > > /* audit_rule_data supports filter rules with both integer and string > > > > * fields. It corresponds with AUDIT_ADD_RULE, AUDIT_DEL_RULE and > > > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > > > > index 4e0a4ac..0ee1e59 100644 > > > > --- a/kernel/auditsc.c > > > > +++ b/kernel/auditsc.c > > > > @@ -2073,6 +2073,92 @@ int audit_set_loginuid(kuid_t loginuid) > > > > return rc; > > > > } > > > > > > > > +static int audit_set_containerid_perm(struct task_struct *task, u64 containerid) > > > > +{ > > > > + struct task_struct *parent; > > > > + u64 pcontainerid, ccontainerid; > > > > + pid_t ppid; > > > > + > > > > + /* Don't allow to set our own containerid */ > > > > + if (current == task) > > > > + return -EPERM; > > > > + /* Don't allow the containerid to be unset */ > > > > + if (!cid_valid(containerid)) > > > > + return -EINVAL; > > > > + /* if we don't have caps, reject */ > > > > + if (!capable(CAP_AUDIT_CONTROL)) > > > > + return -EPERM; > > > > + /* if containerid is unset, allow */ > > > > + if (!audit_containerid_set(task)) > > > > + return 0; > > > I am wondering whether there should be a check for the target process that > > > will receive the containerid to not have CAP_SYS_ADMIN that would otherwise > > > allow it to arbitrarily unshare()/clone() and leave the set of namespaces > > > that may make up the container whose containerid we assign here? > > This is a reasonable question. This has been debated and I understood > > the conclusion was that without a clear definition of a "container", the > > task still remains in that container that just now has more > > sub-namespaces (in the case of hierarchical namespaces), we don't want > > to restrict it in such a way and that allows it to create nested > > containers. I see setns being more problematic if it could switch to > > another existing namespace that was set up by the orchestrator for a > > different container. The coming v2 patchset acknowledges this situation > > with the network namespace being potentially shared by multiple > > containers. > > Are you going to post v2 soon? We would like to build on top of it for IMA > namespacing and auditing inside of IMA namespaces. I don't know if it addresses your specific needs, but V2 was posted on March 16th along with userspace patches: https://www.redhat.com/archives/linux-audit/2018-March/msg00110.html https://www.redhat.com/archives/linux-audit/2018-March/msg00124.html V3 is pending. > Stefan - RGB -- Richard Guy Briggs <rgb@redhat.com> Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635
On 04/18/2018 03:23 PM, Richard Guy Briggs wrote: > On 2018-04-18 14:45, Stefan Berger wrote: >> On 03/15/2018 11:58 PM, Richard Guy Briggs wrote: >>> On 2018-03-15 16:27, Stefan Berger wrote: >>>> On 03/01/2018 02:41 PM, Richard Guy Briggs wrote: >>>>> Implement the proc fs write to set the audit container ID of a process, >>>>> emitting an AUDIT_CONTAINER record to document the event. >>>>> >>>>> This is a write from the container orchestrator task to a proc entry of >>>>> the form /proc/PID/containerid where PID is the process ID of the newly >>>>> created task that is to become the first task in a container, or an >>>>> additional task added to a container. >>>>> >>>>> The write expects up to a u64 value (unset: 18446744073709551615). >>>>> >>>>> This will produce a record such as this: >>>>> type=UNKNOWN[1333] msg=audit(1519903238.968:261): op=set pid=596 uid=0 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 auid=0 tty=pts0 ses=1 opid=596 old-contid=18446744073709551615 contid=123455 res=0 >>>>> >>>>> The "op" field indicates an initial set. The "pid" to "ses" fields are >>>>> the orchestrator while the "opid" field is the object's PID, the process >>>>> being "contained". Old and new container ID values are given in the >>>>> "contid" fields, while res indicates its success. >>>>> >>>>> It is not permitted to self-set, unset or re-set the container ID. A >>>>> child inherits its parent's container ID, but then can be set only once >>>>> after. >>>>> >>>>> See: https://github.com/linux-audit/audit-kernel/issues/32 >>>>> >>>>> >>>>> /* audit_rule_data supports filter rules with both integer and string >>>>> * fields. It corresponds with AUDIT_ADD_RULE, AUDIT_DEL_RULE and >>>>> diff --git a/kernel/auditsc.c b/kernel/auditsc.c >>>>> index 4e0a4ac..0ee1e59 100644 >>>>> --- a/kernel/auditsc.c >>>>> +++ b/kernel/auditsc.c >>>>> @@ -2073,6 +2073,92 @@ int audit_set_loginuid(kuid_t loginuid) >>>>> return rc; >>>>> } >>>>> >>>>> +static int audit_set_containerid_perm(struct task_struct *task, u64 containerid) >>>>> +{ >>>>> + struct task_struct *parent; >>>>> + u64 pcontainerid, ccontainerid; >>>>> + pid_t ppid; >>>>> + >>>>> + /* Don't allow to set our own containerid */ >>>>> + if (current == task) >>>>> + return -EPERM; >>>>> + /* Don't allow the containerid to be unset */ >>>>> + if (!cid_valid(containerid)) >>>>> + return -EINVAL; >>>>> + /* if we don't have caps, reject */ >>>>> + if (!capable(CAP_AUDIT_CONTROL)) >>>>> + return -EPERM; >>>>> + /* if containerid is unset, allow */ >>>>> + if (!audit_containerid_set(task)) >>>>> + return 0; >>>> I am wondering whether there should be a check for the target process that >>>> will receive the containerid to not have CAP_SYS_ADMIN that would otherwise >>>> allow it to arbitrarily unshare()/clone() and leave the set of namespaces >>>> that may make up the container whose containerid we assign here? >>> This is a reasonable question. This has been debated and I understood >>> the conclusion was that without a clear definition of a "container", the >>> task still remains in that container that just now has more >>> sub-namespaces (in the case of hierarchical namespaces), we don't want >>> to restrict it in such a way and that allows it to create nested >>> containers. I see setns being more problematic if it could switch to >>> another existing namespace that was set up by the orchestrator for a >>> different container. The coming v2 patchset acknowledges this situation >>> with the network namespace being potentially shared by multiple >>> containers. >> Are you going to post v2 soon? We would like to build on top of it for IMA >> namespacing and auditing inside of IMA namespaces. > I don't know if it addresses your specific needs, but V2 was posted on > March 16th along with userspace patches: > https://www.redhat.com/archives/linux-audit/2018-March/msg00110.html > https://www.redhat.com/archives/linux-audit/2018-March/msg00124.html > > V3 is pending. Thanks. I hadn't actually looked at primarily due to the ghak and ghau in the title. Whatever these may mean. Does V2 or will V3 prevent a privileged process to setns() to a whole different set of namespaces and still be audited with that initial container id ?
On 2018-04-18 15:39, Stefan Berger wrote: > On 04/18/2018 03:23 PM, Richard Guy Briggs wrote: > > On 2018-04-18 14:45, Stefan Berger wrote: > > > On 03/15/2018 11:58 PM, Richard Guy Briggs wrote: > > > > On 2018-03-15 16:27, Stefan Berger wrote: > > > > > On 03/01/2018 02:41 PM, Richard Guy Briggs wrote: > > > > > > Implement the proc fs write to set the audit container ID of a process, > > > > > > emitting an AUDIT_CONTAINER record to document the event. > > > > > > > > > > > > This is a write from the container orchestrator task to a proc entry of > > > > > > the form /proc/PID/containerid where PID is the process ID of the newly > > > > > > created task that is to become the first task in a container, or an > > > > > > additional task added to a container. > > > > > > > > > > > > The write expects up to a u64 value (unset: 18446744073709551615). > > > > > > > > > > > > This will produce a record such as this: > > > > > > type=UNKNOWN[1333] msg=audit(1519903238.968:261): op=set pid=596 uid=0 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 auid=0 tty=pts0 ses=1 opid=596 old-contid=18446744073709551615 contid=123455 res=0 > > > > > > > > > > > > The "op" field indicates an initial set. The "pid" to "ses" fields are > > > > > > the orchestrator while the "opid" field is the object's PID, the process > > > > > > being "contained". Old and new container ID values are given in the > > > > > > "contid" fields, while res indicates its success. > > > > > > > > > > > > It is not permitted to self-set, unset or re-set the container ID. A > > > > > > child inherits its parent's container ID, but then can be set only once > > > > > > after. > > > > > > > > > > > > See: https://github.com/linux-audit/audit-kernel/issues/32 > > > > > > > > > > > > > > > > > > /* audit_rule_data supports filter rules with both integer and string > > > > > > * fields. It corresponds with AUDIT_ADD_RULE, AUDIT_DEL_RULE and > > > > > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > > > > > > index 4e0a4ac..0ee1e59 100644 > > > > > > --- a/kernel/auditsc.c > > > > > > +++ b/kernel/auditsc.c > > > > > > @@ -2073,6 +2073,92 @@ int audit_set_loginuid(kuid_t loginuid) > > > > > > return rc; > > > > > > } > > > > > > > > > > > > +static int audit_set_containerid_perm(struct task_struct *task, u64 containerid) > > > > > > +{ > > > > > > + struct task_struct *parent; > > > > > > + u64 pcontainerid, ccontainerid; > > > > > > + pid_t ppid; > > > > > > + > > > > > > + /* Don't allow to set our own containerid */ > > > > > > + if (current == task) > > > > > > + return -EPERM; > > > > > > + /* Don't allow the containerid to be unset */ > > > > > > + if (!cid_valid(containerid)) > > > > > > + return -EINVAL; > > > > > > + /* if we don't have caps, reject */ > > > > > > + if (!capable(CAP_AUDIT_CONTROL)) > > > > > > + return -EPERM; > > > > > > + /* if containerid is unset, allow */ > > > > > > + if (!audit_containerid_set(task)) > > > > > > + return 0; > > > > > I am wondering whether there should be a check for the target process that > > > > > will receive the containerid to not have CAP_SYS_ADMIN that would otherwise > > > > > allow it to arbitrarily unshare()/clone() and leave the set of namespaces > > > > > that may make up the container whose containerid we assign here? > > > > This is a reasonable question. This has been debated and I understood > > > > the conclusion was that without a clear definition of a "container", the > > > > task still remains in that container that just now has more > > > > sub-namespaces (in the case of hierarchical namespaces), we don't want > > > > to restrict it in such a way and that allows it to create nested > > > > containers. I see setns being more problematic if it could switch to > > > > another existing namespace that was set up by the orchestrator for a > > > > different container. The coming v2 patchset acknowledges this situation > > > > with the network namespace being potentially shared by multiple > > > > containers. > > > Are you going to post v2 soon? We would like to build on top of it for IMA > > > namespacing and auditing inside of IMA namespaces. > > I don't know if it addresses your specific needs, but V2 was posted on > > March 16th along with userspace patches: > > https://www.redhat.com/archives/linux-audit/2018-March/msg00110.html > > https://www.redhat.com/archives/linux-audit/2018-March/msg00124.html > > > > V3 is pending. > Thanks. I hadn't actually looked at primarily due to the ghak and ghau in > the title. Whatever these may mean. They are Github issue numbers: GHAK: GitHub Audit Kernel GHAU: GitHub Audit Userspace GHAD: GitHub Audit Documentation GHAT: GitHub Audit Testsuite > Does V2 or will V3 prevent a privileged process to setns() to a whole > different set of namespaces and still be audited with that initial container > id ? No, not significantly different from V1 in that respect. It does not prevent setns(), but will maintain its containerid. It will prevent games by blocking a child and parent from setting each other's containerids. It does check that the task being conainered does not yet have any children or peer threads. - RGB -- Richard Guy Briggs <rgb@redhat.com> Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635
diff --git a/fs/proc/base.c b/fs/proc/base.c index 60316b5..6ce4fbe 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -1299,6 +1299,41 @@ static ssize_t proc_sessionid_read(struct file * file, char __user * buf, .read = proc_sessionid_read, .llseek = generic_file_llseek, }; + +static ssize_t proc_containerid_write(struct file *file, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct inode *inode = file_inode(file); + u64 containerid; + int rv; + struct task_struct *task = get_proc_task(inode); + + if (!task) + return -ESRCH; + if (*ppos != 0) { + /* No partial writes. */ + put_task_struct(task); + return -EINVAL; + } + + rv = kstrtou64_from_user(buf, count, 10, &containerid); + if (rv < 0) { + put_task_struct(task); + return rv; + } + + rv = audit_set_containerid(task, containerid); + put_task_struct(task); + if (rv < 0) + return rv; + return count; +} + +static const struct file_operations proc_containerid_operations = { + .write = proc_containerid_write, + .llseek = generic_file_llseek, +}; + #endif #ifdef CONFIG_FAULT_INJECTION @@ -2961,6 +2996,7 @@ static int proc_pid_patch_state(struct seq_file *m, struct pid_namespace *ns, #ifdef CONFIG_AUDITSYSCALL REG("loginuid", S_IWUSR|S_IRUGO, proc_loginuid_operations), REG("sessionid", S_IRUGO, proc_sessionid_operations), + REG("containerid", S_IWUSR, proc_containerid_operations), #endif #ifdef CONFIG_FAULT_INJECTION REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations), @@ -3355,6 +3391,7 @@ static int proc_tid_comm_permission(struct inode *inode, int mask) #ifdef CONFIG_AUDITSYSCALL REG("loginuid", S_IWUSR|S_IRUGO, proc_loginuid_operations), REG("sessionid", S_IRUGO, proc_sessionid_operations), + REG("containerid", S_IWUSR, proc_containerid_operations), #endif #ifdef CONFIG_FAULT_INJECTION REG("make-it-fail", S_IRUGO|S_IWUSR, proc_fault_inject_operations), diff --git a/include/linux/audit.h b/include/linux/audit.h index af410d9..fe4ba3f 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -29,6 +29,7 @@ #define AUDIT_INO_UNSET ((unsigned long)-1) #define AUDIT_DEV_UNSET ((dev_t)-1) +#define INVALID_CID AUDIT_CID_UNSET struct audit_sig_info { uid_t uid; @@ -321,6 +322,7 @@ static inline void audit_ptrace(struct task_struct *t) extern int auditsc_get_stamp(struct audit_context *ctx, struct timespec64 *t, unsigned int *serial); extern int audit_set_loginuid(kuid_t loginuid); +extern int audit_set_containerid(struct task_struct *tsk, u64 containerid); static inline kuid_t audit_get_loginuid(struct task_struct *tsk) { @@ -332,6 +334,11 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk) return tsk->sessionid; } +static inline u64 audit_get_containerid(struct task_struct *tsk) +{ + return tsk->containerid; +} + extern void __audit_ipc_obj(struct kern_ipc_perm *ipcp); extern void __audit_ipc_set_perm(unsigned long qbytes, uid_t uid, gid_t gid, umode_t mode); extern void __audit_bprm(struct linux_binprm *bprm); @@ -517,6 +524,10 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk) { return -1; } +static inline kuid_t audit_get_containerid(struct task_struct *tsk) +{ + return INVALID_CID; +} static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp) { } static inline void audit_ipc_set_perm(unsigned long qbytes, uid_t uid, @@ -581,6 +592,11 @@ static inline bool audit_loginuid_set(struct task_struct *tsk) return uid_valid(audit_get_loginuid(tsk)); } +static inline bool audit_containerid_set(struct task_struct *tsk) +{ + return audit_get_containerid(tsk) != INVALID_CID; +} + static inline void audit_log_string(struct audit_buffer *ab, const char *buf) { audit_log_n_string(ab, buf, strlen(buf)); diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 6a53262..046bd0a 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -18,6 +18,7 @@ #include <linux/sched/rt.h> #include <linux/livepatch.h> #include <linux/mm_types.h> +#include <linux/audit.h> #include <asm/thread_info.h> @@ -120,7 +121,8 @@ #ifdef CONFIG_AUDITSYSCALL #define INIT_IDS \ .loginuid = INVALID_UID, \ - .sessionid = (unsigned int)-1, + .sessionid = (unsigned int)-1, \ + .containerid = INVALID_CID, #else #define INIT_IDS #endif diff --git a/include/linux/sched.h b/include/linux/sched.h index d258826..1b82191 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -796,6 +796,7 @@ struct task_struct { #ifdef CONFIG_AUDITSYSCALL kuid_t loginuid; unsigned int sessionid; + u64 containerid; #endif struct seccomp seccomp; diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h index 4e61a9e..921a71f 100644 --- a/include/uapi/linux/audit.h +++ b/include/uapi/linux/audit.h @@ -71,6 +71,7 @@ #define AUDIT_TTY_SET 1017 /* Set TTY auditing status */ #define AUDIT_SET_FEATURE 1018 /* Turn an audit feature on or off */ #define AUDIT_GET_FEATURE 1019 /* Get which features are enabled */ +#define AUDIT_CONTAINER 1020 /* Define the container id and information */ #define AUDIT_FIRST_USER_MSG 1100 /* Userspace messages mostly uninteresting to kernel */ #define AUDIT_USER_AVC 1107 /* We filter this differently */ @@ -465,6 +466,7 @@ struct audit_tty_status { }; #define AUDIT_UID_UNSET (unsigned int)-1 +#define AUDIT_CID_UNSET ((u64)-1) /* audit_rule_data supports filter rules with both integer and string * fields. It corresponds with AUDIT_ADD_RULE, AUDIT_DEL_RULE and diff --git a/kernel/auditsc.c b/kernel/auditsc.c index 4e0a4ac..0ee1e59 100644 --- a/kernel/auditsc.c +++ b/kernel/auditsc.c @@ -2073,6 +2073,92 @@ int audit_set_loginuid(kuid_t loginuid) return rc; } +static int audit_set_containerid_perm(struct task_struct *task, u64 containerid) +{ + struct task_struct *parent; + u64 pcontainerid, ccontainerid; + pid_t ppid; + + /* Don't allow to set our own containerid */ + if (current == task) + return -EPERM; + /* Don't allow the containerid to be unset */ + if (!cid_valid(containerid)) + return -EINVAL; + /* if we don't have caps, reject */ + if (!capable(CAP_AUDIT_CONTROL)) + return -EPERM; + /* if containerid is unset, allow */ + if (!audit_containerid_set(task)) + return 0; + /* it is already set, and not inherited from the parent, reject */ + ccontainerid = audit_get_containerid(task); + rcu_read_lock(); + parent = rcu_dereference(task->real_parent); + rcu_read_unlock(); + task_lock(parent); + pcontainerid = audit_get_containerid(parent); + ppid = task_tgid_nr(parent); + task_unlock(parent); + if (ccontainerid != pcontainerid) + return -EPERM; + return 0; +} + +static void audit_log_set_containerid(struct task_struct *task, u64 oldcontainerid, + u64 containerid, int rc) +{ + struct audit_buffer *ab; + uid_t uid; + struct tty_struct *tty; + + if (!audit_enabled) + return; + + ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONTAINER); + if (!ab) + return; + + uid = from_kuid(&init_user_ns, task_uid(current)); + tty = audit_get_tty(current); + + audit_log_format(ab, "op=set pid=%d uid=%u", task_tgid_nr(current), uid); + audit_log_task_context(ab); + audit_log_format(ab, " auid=%u tty=%s ses=%u opid=%d old-contid=%llu contid=%llu res=%d", + from_kuid(&init_user_ns, audit_get_loginuid(current)), + tty ? tty_name(tty) : "(none)", audit_get_sessionid(current), + task_tgid_nr(task), oldcontainerid, containerid, !rc); + + audit_put_tty(tty); + audit_log_end(ab); +} + +/** + * audit_set_containerid - set current task's audit_context containerid + * @containerid: containerid value + * + * Returns 0 on success, -EPERM on permission failure. + * + * Called (set) from fs/proc/base.c::proc_containerid_write(). + */ +int audit_set_containerid(struct task_struct *task, u64 containerid) +{ + u64 oldcontainerid; + int rc; + + oldcontainerid = audit_get_containerid(task); + + rc = audit_set_containerid_perm(task, containerid); + if (!rc) { + task_lock(task); + task->containerid = containerid; + task_unlock(task); + } + + audit_log_set_containerid(task, oldcontainerid, containerid, rc); + return rc; +} + /** * __audit_mq_open - record audit data for a POSIX MQ open * @oflag: open flag
Implement the proc fs write to set the audit container ID of a process, emitting an AUDIT_CONTAINER record to document the event. This is a write from the container orchestrator task to a proc entry of the form /proc/PID/containerid where PID is the process ID of the newly created task that is to become the first task in a container, or an additional task added to a container. The write expects up to a u64 value (unset: 18446744073709551615). This will produce a record such as this: type=UNKNOWN[1333] msg=audit(1519903238.968:261): op=set pid=596 uid=0 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 auid=0 tty=pts0 ses=1 opid=596 old-contid=18446744073709551615 contid=123455 res=0 The "op" field indicates an initial set. The "pid" to "ses" fields are the orchestrator while the "opid" field is the object's PID, the process being "contained". Old and new container ID values are given in the "contid" fields, while res indicates its success. It is not permitted to self-set, unset or re-set the container ID. A child inherits its parent's container ID, but then can be set only once after. See: https://github.com/linux-audit/audit-kernel/issues/32 Signed-off-by: Richard Guy Briggs <rgb@redhat.com> --- fs/proc/base.c | 37 ++++++++++++++++++++ include/linux/audit.h | 16 +++++++++ include/linux/init_task.h | 4 ++- include/linux/sched.h | 1 + include/uapi/linux/audit.h | 2 ++ kernel/auditsc.c | 86 ++++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 145 insertions(+), 1 deletion(-)