[PATCH] Enable splitting the logs to both auditd and kernel simultaneously
William Roberts
bill.c.roberts at gmail.com
Fri May 24 18:35:39 UTC 2013
By any chance do you have a public branch somewhere I can pull these
patches from. Gmail and patches is a pain..
Bill
On Fri, May 24, 2013 at 10:29 AM, William Roberts
<bill.c.roberts at gmail.com>wrote:
> Ok I can port on top of your series. The KConfig default is really nice,
> as it allows for an ignorant userspace. However, I could nix that if its a
> show stopper.
>
> Bill
>
>
> On Fri, May 24, 2013 at 9:34 AM, Eric Paris <eparis at parisplace.org> wrote:
>
>> On Wed, 2013-05-22 at 19:18 -0700, William Roberts wrote:
>> > This need came about in Samsung's mobile products. Id like to see and
>> > attempt to get this mainstreamed. Any feedback would be greatly
>> > appreciated. Thanks.
>>
>> My first thought is that I just sent a patch to introduce a flexible
>> on/off flipping of bits for audit system features. Rather timely, so we
>> don't have to keep introducing message types. AUDIT_SET/AUDIT_GET
>> certainly weren't well thought out in that way. I'd like your thoughts
>> on those patches (really 1/7 does the heavy lifting 6/7 and 7/7 use
>> it)
>>
>> I thinking porting on top of my series will result in your patch being
>> about 10 lines.
>>
>> I also don't love the name. This isn't about splitting logs, it's about
>> also logging to kmsg.
>>
>> Do we need the Kconfig default? I'd think we should be able to get this
>> set early enough in userspace. Any messages before auditd are going to
>> go to kmsg. I envision that we should be able to set features in the
>> audit.rules so you should be able to turn this on before auditd starts
>> and things would stop going to kmsg.
>>
>> But I don't see a problem with it. If you port on top of this series
>> I'm ok with queuing for 3.11
>>
>> > On Wed, May 22, 2013 at 7:16 PM, William Roberts
>> > <bill.c.roberts at gmail.com> wrote:
>> > Allow the audit subsystem to send audit events to both the
>> > kernel
>> > message buffer and auditd at the same time.
>> >
>> > Signed-off-by: William Roberts <w.roberts at sta.samsung.com>
>> > ---
>> > include/uapi/linux/audit.h | 11 ++++++++++
>> > init/Kconfig | 8 +++++++
>> > kernel/audit.c | 52
>> > ++++++++++++++++++++++++++++++++++++++++------
>> > kernel/audit.h | 6 ++++++
>> > 4 files changed, 71 insertions(+), 6 deletions(-)
>> >
>> > diff --git a/include/uapi/linux/audit.h
>> > b/include/uapi/linux/audit.h
>> > index 75cef3f..0af5d78 100644
>> > --- a/include/uapi/linux/audit.h
>> > +++ b/include/uapi/linux/audit.h
>> > @@ -68,6 +68,8 @@
>> > #define AUDIT_MAKE_EQUIV 1015 /* Append to watched
>> > tree */
>> > #define AUDIT_TTY_GET 1016 /* Get TTY auditing
>> > status */
>> > #define AUDIT_TTY_SET 1017 /* Set TTY auditing
>> > status */
>> > +#define AUDIT_LOGSPLIT_GET 1018 /* Get logsplit
>> > status */
>> > +#define AUDIT_LOGSPLIT_SET 1019 /* Set logsplit
>> > status */
>> >
>> > #define AUDIT_FIRST_USER_MSG 1100 /* Userspace messages
>> > mostly uninteresting to kernel */
>> > #define AUDIT_USER_AVC 1107 /* We filter this
>> > differently */
>> > @@ -321,6 +323,10 @@ enum {
>> > #define AUDIT_FAIL_PRINTK 1
>> > #define AUDIT_FAIL_PANIC 2
>> >
>> > +/* Audit splitlog options */
>> > +#define AUDIT_LOGSPLIT_OFF 0
>> > +#define AUDIT_LOGSPLIT_ON 1
>> > +
>> > /* distinguish syscall tables */
>> > #define __AUDIT_ARCH_64BIT 0x80000000
>> > #define __AUDIT_ARCH_LE 0x40000000
>> > @@ -374,6 +380,11 @@ struct audit_tty_status {
>> > __u32 log_passwd; /* 1 = enabled, 0 =
>> > disabled */
>> > };
>> >
>> > +struct audit_logsplit_status {
>> > + __u32 enabled; /* AUDIT_LOGSPLIT_ON
>> > or
>> > +
>> > AUDIT_LOGSPLIT_OFF */
>> > +};
>> > +
>> > /* audit_rule_data supports filter rules with both integer
>> > and string
>> > * fields. It corresponds with AUDIT_ADD_RULE,
>> > AUDIT_DEL_RULE and
>> > * AUDIT_LIST_RULES requests.
>> > diff --git a/init/Kconfig b/init/Kconfig
>> > index 9d3a788..52efca6 100644
>> > --- a/init/Kconfig
>> > +++ b/init/Kconfig
>> > @@ -286,6 +286,14 @@ config AUDIT_LOGINUID_IMMUTABLE
>> > one to drop potentially dangerous capabilites from
>> > the login tasks,
>> > but may not be backwards compatible with older init
>> > systems.
>> >
>> > +config AUDIT_SPLITLOG
>> > + bool "Split audit messages to userspace and kernel by
>> > default"
>> > + depends on AUDIT
>> > + help
>> > + Setting this to true will cause the audit messages
>> > to be split
>> > + by default to both the kernel message log and a
>> > userspace audit
>> > + daemon if registered.
>> > +
>> > source "kernel/irq/Kconfig"
>> > source "kernel/time/Kconfig"
>> >
>> > diff --git a/kernel/audit.c b/kernel/audit.c
>> > index 21c7fa6..ccd2f60 100644
>> > --- a/kernel/audit.c
>> > +++ b/kernel/audit.c
>> > @@ -88,6 +88,9 @@ static int audit_default;
>> > /* If auditing cannot proceed, audit_failure selects what
>> > happens. */
>> > static int audit_failure = AUDIT_FAIL_PRINTK;
>> >
>> > +/* Whether or not logsplit is enabled */
>> > +static int audit_logsplit = AUDIT_SPLITLOG_INIT;
>> > +
>> > /*
>> > * If audit records are to be written to the netlink socket,
>> > audit_pid
>> > * contains the pid of the auditd process and
>> > audit_nlk_portid contains
>> > @@ -343,6 +346,17 @@ static int audit_set_failure(int state)
>> > return audit_do_config_change("audit_failure",
>> > &audit_failure, state);
>> > }
>> >
>> > +static int audit_set_logsplit(int state)
>> > +{
>> > + if (state != AUDIT_LOGSPLIT_OFF
>> > + && state != AUDIT_LOGSPLIT_ON)
>> > + return -EINVAL;
>> > +
>> > + return audit_do_config_change("audit_logsplit",
>> > &audit_logsplit, state);
>> > +}
>> > +
>> > +
>> > +
>> > /*
>> > * Queue skbs to be sent to auditd when/if it comes back.
>> > These skbs should
>> > * already have been sent via prink/syslog and so if these
>> > messages are dropped
>> > @@ -361,11 +375,8 @@ static void audit_hold_skb(struct sk_buff
>> > *skb)
>> > kfree_skb(skb);
>> > }
>> >
>> > -/*
>> > - * For one reason or another this nlh isn't getting delivered
>> > to the userspace
>> > - * audit daemon, just send it to printk.
>> > - */
>> > -static void audit_printk_skb(struct sk_buff *skb)
>> > +/* Just printks the skb, no audit_hold or free of any kind */
>> > +static void __audit_printk_skb(struct sk_buff *skb)
>> > {
>> > struct nlmsghdr *nlh = nlmsg_hdr(skb);
>> > char *data = nlmsg_data(nlh);
>> > @@ -376,7 +387,14 @@ static void audit_printk_skb(struct
>> > sk_buff *skb)
>> > else
>> > audit_log_lost("printk limit exceeded
>> > \n");
>> > }
>> > -
>> > +}
>> > +/*
>> > + * For one reason or another this nlh isn't getting delivered
>> > to the userspace
>> > + * audit daemon, just send it to printk.
>> > + */
>> > +static void audit_printk_skb(struct sk_buff *skb)
>> > +{
>> > + __audit_printk_skb(skb);
>> > audit_hold_skb(skb);
>> > }
>> >
>> > @@ -590,6 +608,8 @@ static int audit_netlink_ok(struct sk_buff
>> > *skb, u16 msg_type)
>> > case AUDIT_SIGNAL_INFO:
>> > case AUDIT_TTY_GET:
>> > case AUDIT_TTY_SET:
>> > + case AUDIT_LOGSPLIT_GET:
>> > + case AUDIT_LOGSPLIT_SET:
>> > case AUDIT_TRIM:
>> > case AUDIT_MAKE_EQUIV:
>> > if (!capable(CAP_AUDIT_CONTROL))
>> > @@ -843,7 +863,24 @@ static int audit_receive_msg(struct
>> > sk_buff *skb, struct nlmsghdr *nlh)
>> > spin_unlock(&tsk->sighand->siglock);
>> > break;
>> > }
>> > + case AUDIT_LOGSPLIT_GET: {
>> > + struct audit_logsplit_status s;
>> > + s.enabled = audit_logsplit;
>> > + audit_send_reply(NETLINK_CB(skb).portid, seq,
>> > + AUDIT_LOGSPLIT_GET, 0, 0, &s,
>> > sizeof(s));
>> > + break;
>> > + }
>> > + case AUDIT_LOGSPLIT_SET: {
>> > + struct audit_logsplit_status *s;
>> > + if (nlh->nlmsg_len < sizeof(struct
>> > audit_logsplit_status))
>> > + return -EINVAL;
>> > + s = data;
>> > + err = audit_set_logsplit(s->enabled);
>> > + break;
>> > + }
>> > +
>> > default:
>> > + printk(KERN_ERR "Unkown audit command");
>> > err = -EINVAL;
>> > break;
>> > }
>> > @@ -1670,6 +1707,9 @@ void audit_log_end(struct audit_buffer
>> > *ab)
>> > nlh->nlmsg_len = ab->skb->len - NLMSG_HDRLEN;
>> >
>> > if (audit_pid) {
>> > + if (audit_logsplit ==
>> > AUDIT_LOGSPLIT_ON)
>> > + __audit_printk_skb(ab->skb);
>> > +
>> > skb_queue_tail(&audit_skb_queue,
>> > ab->skb);
>> > wake_up_interruptible(&kauditd_wait);
>> > } else {
>> > diff --git a/kernel/audit.h b/kernel/audit.h
>> > index 1c95131..ef43bb1 100644
>> > --- a/kernel/audit.h
>> > +++ b/kernel/audit.h
>> > @@ -321,4 +321,10 @@ extern struct list_head
>> > *audit_killed_trees(void);
>> > #define audit_filter_inodes(t,c) AUDIT_DISABLED
>> > #endif
>> >
>> > +#ifdef CONFIG_AUDIT_SPLITLOG
>> > +#define AUDIT_SPLITLOG_INIT AUDIT_LOGSPLIT_ON
>> > +#else
>> > +#define AUDIT_SPLITLOG_INIT AUDIT_LOGSPLIT_OFF
>> > +#endif
>> > +
>> > extern struct mutex audit_cmd_mutex;
>> > --
>> > 1.8.2.2
>> >
>> >
>> >
>> >
>> >
>> > --
>> > Respectfully,
>> >
>> > William C Roberts
>> >
>> >
>> > --
>> > Linux-audit mailing list
>> > Linux-audit at redhat.com
>> > https://www.redhat.com/mailman/listinfo/linux-audit
>>
>>
>>
>
>
> --
> Respectfully,
>
> William C Roberts
>
>
--
Respectfully,
William C Roberts
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