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Merge tag 'audit-pr-20180403' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit

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Pull audit updates from Paul Moore:
 "We didn't have anything to send for v4.16, but we're back with a
  little more than usual for v4.17.

  Eleven patches in total, most fall into the small fix category, but
  there are three non-trivial changes worth calling out:

   - the audit entry filter is being removed after deprecating it for
     quite a while (years of no one really using it because it turns out
     to be not very practical)

   - created our own version of "__mutex_owner()" because the locking
     folks were upset we were using theirs

   - improved our handling of kernel command line parameters to make
     them more forgiving

   - we fixed auditing of symlink operations

  Everything passes the audit-testsuite and as of a few minutes ago it
  merges well with your tree"

* tag 'audit-pr-20180403' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/audit:
  audit: add refused symlink to audit_names
  audit: remove path param from link denied function
  audit: link denied should not directly generate PATH record
  audit: make ANOM_LINK obey audit_enabled and audit_dummy_context
  audit: do not panic on invalid boot parameter
  audit: track the owner of the command mutex ourselves
  audit: return on memory error to avoid null pointer dereference
  audit: bail before bug check if audit disabled
  audit: deprecate the AUDIT_FILTER_ENTRY filter
  audit: session ID should not set arch quick field pointer
  audit: update bugtracker and source URIs
This commit is contained in:
Linus Torvalds
2018-04-06 15:01:25 -07:00
parent 69824bcc4b ea841bafda
commit 6ad11bdd57
9 changed files with 106 additions and 66 deletions
Download Patch File Download Diff File Expand all files Collapse all files

108
kernel/audit.c
View File

@@ -38,7 +38,8 @@
* 6) Support low-overhead kernel-based filtering to minimize the
* information that must be passed to user-space.
*
* Example user-space utilities: http://people.redhat.com/sgrubb/audit/
* Audit userspace, documentation, tests, and bug/issue trackers:
* https://github.com/linux-audit
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -180,9 +181,21 @@ static char *audit_feature_names[2] = {
"loginuid_immutable",
};
/* Serialize requests from userspace. */
DEFINE_MUTEX(audit_cmd_mutex);
/**
* struct audit_ctl_mutex - serialize requests from userspace
* @lock: the mutex used for locking
* @owner: the task which owns the lock
*
* Description:
* This is the lock struct used to ensure we only process userspace requests
* in an orderly fashion. We can't simply use a mutex/lock here because we
* need to track lock ownership so we don't end up blocking the lock owner in
* audit_log_start() or similar.
*/
static struct audit_ctl_mutex {
struct mutex lock;
void *owner;
} audit_cmd_mutex;
/* AUDIT_BUFSIZ is the size of the temporary buffer used for formatting
* audit records. Since printk uses a 1024 byte buffer, this buffer
@@ -226,6 +239,36 @@ int auditd_test_task(struct task_struct *task)
return rc;
}
/**
* audit_ctl_lock - Take the audit control lock
*/
void audit_ctl_lock(void)
{
mutex_lock(&audit_cmd_mutex.lock);
audit_cmd_mutex.owner = current;
}
/**
* audit_ctl_unlock - Drop the audit control lock
*/
void audit_ctl_unlock(void)
{
audit_cmd_mutex.owner = NULL;
mutex_unlock(&audit_cmd_mutex.lock);
}
/**
* audit_ctl_owner_current - Test to see if the current task owns the lock
*
* Description:
* Return true if the current task owns the audit control lock, false if it
* doesn't own the lock.
*/
static bool audit_ctl_owner_current(void)
{
return (current == audit_cmd_mutex.owner);
}
/**
* auditd_pid_vnr - Return the auditd PID relative to the namespace
*
@@ -860,8 +903,8 @@ int audit_send_list(void *_dest)
struct sock *sk = audit_get_sk(dest->net);
/* wait for parent to finish and send an ACK */
mutex_lock(&audit_cmd_mutex);
mutex_unlock(&audit_cmd_mutex);
audit_ctl_lock();
audit_ctl_unlock();
while ((skb = __skb_dequeue(&dest->q)) != NULL)
netlink_unicast(sk, skb, dest->portid, 0);
@@ -902,8 +945,8 @@ static int audit_send_reply_thread(void *arg)
struct audit_reply *reply = (struct audit_reply *)arg;
struct sock *sk = audit_get_sk(reply->net);
mutex_lock(&audit_cmd_mutex);
mutex_unlock(&audit_cmd_mutex);
audit_ctl_lock();
audit_ctl_unlock();
/* Ignore failure. It'll only happen if the sender goes away,
because our timeout is set to infinite. */
@@ -1058,6 +1101,8 @@ static void audit_log_feature_change(int which, u32 old_feature, u32 new_feature
return;
ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_FEATURE_CHANGE);
if (!ab)
return;
audit_log_task_info(ab, current);
audit_log_format(ab, " feature=%s old=%u new=%u old_lock=%u new_lock=%u res=%d",
audit_feature_names[which], !!old_feature, !!new_feature,
@@ -1466,7 +1511,7 @@ static void audit_receive(struct sk_buff *skb)
nlh = nlmsg_hdr(skb);
len = skb->len;
mutex_lock(&audit_cmd_mutex);
audit_ctl_lock();
while (nlmsg_ok(nlh, len)) {
err = audit_receive_msg(skb, nlh);
/* if err or if this message says it wants a response */
@@ -1475,7 +1520,7 @@ static void audit_receive(struct sk_buff *skb)
nlh = nlmsg_next(nlh, &len);
}
mutex_unlock(&audit_cmd_mutex);
audit_ctl_unlock();
}
/* Run custom bind function on netlink socket group connect or bind requests. */
@@ -1547,6 +1592,9 @@ static int __init audit_init(void)
for (i = 0; i < AUDIT_INODE_BUCKETS; i++)
INIT_LIST_HEAD(&audit_inode_hash[i]);
mutex_init(&audit_cmd_mutex.lock);
audit_cmd_mutex.owner = NULL;
pr_info("initializing netlink subsys (%s)\n",
audit_default ? "enabled" : "disabled");
register_pernet_subsys(&audit_net_ops);
@@ -1567,19 +1615,26 @@ static int __init audit_init(void)
}
postcore_initcall(audit_init);
/* Process kernel command-line parameter at boot time. audit=0 or audit=1. */
/*
* Process kernel command-line parameter at boot time.
* audit={0|off} or audit={1|on}.
*/
static int __init audit_enable(char *str)
{
long val;
if (kstrtol(str, 0, &val))
panic("audit: invalid 'audit' parameter value (%s)\n", str);
audit_default = (val ? AUDIT_ON : AUDIT_OFF);
if (!strcasecmp(str, "off") || !strcmp(str, "0"))
audit_default = AUDIT_OFF;
else if (!strcasecmp(str, "on") || !strcmp(str, "1"))
audit_default = AUDIT_ON;
else {
pr_err("audit: invalid 'audit' parameter value (%s)\n", str);
audit_default = AUDIT_ON;
}
if (audit_default == AUDIT_OFF)
audit_initialized = AUDIT_DISABLED;
if (audit_set_enabled(audit_default))
panic("audit: error setting audit state (%d)\n", audit_default);
pr_err("audit: error setting audit state (%d)\n",
audit_default);
pr_info("%s\n", audit_default ?
"enabled (after initialization)" : "disabled (until reboot)");
@@ -1710,8 +1765,7 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
* using a PID anchored in the caller's namespace
* 2. generator holding the audit_cmd_mutex - we don't want to block
* while holding the mutex */
if (!(auditd_test_task(current) ||
(current == __mutex_owner(&audit_cmd_mutex)))) {
if (!(auditd_test_task(current) || audit_ctl_owner_current())) {
long stime = audit_backlog_wait_time;
while (audit_backlog_limit &&
@@ -2254,33 +2308,23 @@ EXPORT_SYMBOL(audit_log_task_info);
/**
* audit_log_link_denied - report a link restriction denial
* @operation: specific link operation
* @link: the path that triggered the restriction
*/
void audit_log_link_denied(const char *operation, const struct path *link)
void audit_log_link_denied(const char *operation)
{
struct audit_buffer *ab;
struct audit_names *name;
name = kzalloc(sizeof(*name), GFP_NOFS);
if (!name)
if (!audit_enabled || audit_dummy_context())
return;
/* Generate AUDIT_ANOM_LINK with subject, operation, outcome. */
ab = audit_log_start(current->audit_context, GFP_KERNEL,
AUDIT_ANOM_LINK);
if (!ab)
goto out;
return;
audit_log_format(ab, "op=%s", operation);
audit_log_task_info(ab, current);
audit_log_format(ab, " res=0");
audit_log_end(ab);
/* Generate AUDIT_PATH record with object. */
name->type = AUDIT_TYPE_NORMAL;
audit_copy_inode(name, link->dentry, d_backing_inode(link->dentry));
audit_log_name(current->audit_context, name, link, 0, NULL);
out:
kfree(name);
}
/**