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Date: Thu, 21 Apr 2016 14:14:01 -0400
From: Richard Guy Briggs <rgb@...hat.com>
To: linux-audit@...hat.com, linux-kernel@...r.kernel.org
Cc: Richard Guy Briggs <rgb@...hat.com>, peter@...leysoftware.com,
sgrubb@...hat.com, pmoore@...hat.com, eparis@...hat.com
Subject: [PATCH V4] audit: add tty field to LOGIN event
The tty field was missing from AUDIT_LOGIN events.
Refactor code to create a new function audit_get_tty(), using it to
replace the call in audit_log_task_info() and to add it to
audit_log_set_loginuid(). Lock and bump the kref to protect it, adding
audit_put_tty() alias to decrement it.
Signed-off-by: Richard Guy Briggs <rgb@...hat.com>
---
V4: Add missing prototype for audit_put_tty() when audit syscall is not
enabled (MIPS).
V3: Introduce audit_put_tty() alias to decrement kref.
V2: Use kref to protect tty signal struct while in use.
---
include/linux/audit.h | 24 ++++++++++++++++++++++++
kernel/audit.c | 18 +++++-------------
kernel/auditsc.c | 8 ++++++--
3 files changed, 35 insertions(+), 15 deletions(-)
diff --git a/include/linux/audit.h b/include/linux/audit.h
index b40ed5d..32cdafb 100644
--- a/include/linux/audit.h
+++ b/include/linux/audit.h
@@ -26,6 +26,7 @@
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <uapi/linux/audit.h>
+#include <linux/tty.h>
#define AUDIT_INO_UNSET ((unsigned long)-1)
#define AUDIT_DEV_UNSET ((dev_t)-1)
@@ -343,6 +344,23 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
return tsk->sessionid;
}
+static inline struct tty_struct *audit_get_tty(struct task_struct *tsk)
+{
+ struct tty_struct *tty = NULL;
+ unsigned long flags;
+
+ spin_lock_irqsave(&tsk->sighand->siglock, flags);
+ if (tsk->signal)
+ tty = tty_kref_get(tsk->signal->tty);
+ spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
+ return tty;
+}
+
+static inline void audit_put_tty(struct tty_struct *tty)
+{
+ tty_kref_put(tty);
+}
+
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);
@@ -500,6 +518,12 @@ static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
{
return -1;
}
+static inline struct tty_struct *audit_get_tty(struct task_struct *tsk)
+{
+ return NULL;
+}
+static inline void audit_put_tty(struct tty_struct *tty)
+{ }
static inline void audit_ipc_obj(struct kern_ipc_perm *ipcp)
{ }
static inline void audit_ipc_set_perm(unsigned long qbytes, uid_t uid,
diff --git a/kernel/audit.c b/kernel/audit.c
index 3a3e5de..7edd776 100644
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -64,7 +64,6 @@
#include <linux/security.h>
#endif
#include <linux/freezer.h>
-#include <linux/tty.h>
#include <linux/pid_namespace.h>
#include <net/netns/generic.h>
@@ -1873,21 +1872,14 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
{
const struct cred *cred;
char comm[sizeof(tsk->comm)];
- char *tty;
+ struct tty_struct *tty;
if (!ab)
return;
/* tsk == current */
cred = current_cred();
-
- spin_lock_irq(&tsk->sighand->siglock);
- if (tsk->signal && tsk->signal->tty && tsk->signal->tty->name)
- tty = tsk->signal->tty->name;
- else
- tty = "(none)";
- spin_unlock_irq(&tsk->sighand->siglock);
-
+ tty = audit_get_tty(tsk);
audit_log_format(ab,
" ppid=%d pid=%d auid=%u uid=%u gid=%u"
" euid=%u suid=%u fsuid=%u"
@@ -1903,11 +1895,11 @@ void audit_log_task_info(struct audit_buffer *ab, struct task_struct *tsk)
from_kgid(&init_user_ns, cred->egid),
from_kgid(&init_user_ns, cred->sgid),
from_kgid(&init_user_ns, cred->fsgid),
- tty, audit_get_sessionid(tsk));
-
+ tty ? tty_name(tty) : "(none)",
+ audit_get_sessionid(tsk));
+ audit_put_tty(tty);
audit_log_format(ab, " comm=");
audit_log_untrustedstring(ab, get_task_comm(comm, tsk));
-
audit_log_d_path_exe(ab, tsk->mm);
audit_log_task_context(ab);
}
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index 195ffae..71e14d8 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -1980,6 +1980,7 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
{
struct audit_buffer *ab;
uid_t uid, oldloginuid, loginuid;
+ struct tty_struct *tty;
if (!audit_enabled)
return;
@@ -1987,14 +1988,17 @@ static void audit_log_set_loginuid(kuid_t koldloginuid, kuid_t kloginuid,
uid = from_kuid(&init_user_ns, task_uid(current));
oldloginuid = from_kuid(&init_user_ns, koldloginuid);
loginuid = from_kuid(&init_user_ns, kloginuid),
+ tty = audit_get_tty(current);
ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_LOGIN);
if (!ab)
return;
audit_log_format(ab, "pid=%d uid=%u", task_pid_nr(current), uid);
audit_log_task_context(ab);
- audit_log_format(ab, " old-auid=%u auid=%u old-ses=%u ses=%u res=%d",
- oldloginuid, loginuid, oldsessionid, sessionid, !rc);
+ audit_log_format(ab, " old-auid=%u auid=%u tty=%s old-ses=%u ses=%u res=%d",
+ oldloginuid, loginuid, tty ? tty_name(tty) : "(none)",
+ oldsessionid, sessionid, !rc);
+ audit_put_tty(tty);
audit_log_end(ab);
}
--
1.7.1
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