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From: Paul Moore <paul@paul-moore.com>
To: linux-security-module@vger.kernel.org, selinux@vger.kernel.org,
	linux-audit@redhat.com, io-uring@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	Kumar Kartikeya Dwivedi <memxor@gmail.com>,
	Jens Axboe <axboe@kernel.dk>,
	Alexander Viro <viro@zeniv.linux.org.uk>
Subject: [RFC PATCH 4/9] audit: add filtering for io_uring records
Date: Fri, 21 May 2021 17:50:06 -0400	[thread overview]
Message-ID: <162163380685.8379.17381053199011043757.stgit@sifl> (raw)
In-Reply-To: <162163367115.8379.8459012634106035341.stgit@sifl>

WARNING - This is a work in progress and should not be merged
anywhere important.  It is almost surely not complete, and while it
probably compiles it likely hasn't been booted and will do terrible
things.  You have been warned.

This patch adds basic audit io_uring filtering, using as much of the
existing audit filtering infrastructure as possible.  In order to do
this we reuse the audit filter rule's syscall mask for the io_uring
operation and we create a new filter for io_uring operations as
AUDIT_FILTER_URING_EXIT/audit_filter_list[7].

<TODO - provide some additional guidance for the userspace tools>

Signed-off-by: Paul Moore <paul@paul-moore.com>
---
 include/uapi/linux/audit.h |    3 +-
 kernel/auditfilter.c       |    4 ++-
 kernel/auditsc.c           |   65 ++++++++++++++++++++++++++++++++++----------
 3 files changed, 55 insertions(+), 17 deletions(-)

diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index b26e0c435e8b..621eb3c1076e 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -167,8 +167,9 @@
 #define AUDIT_FILTER_EXCLUDE	0x05	/* Apply rule before record creation */
 #define AUDIT_FILTER_TYPE	AUDIT_FILTER_EXCLUDE /* obsolete misleading naming */
 #define AUDIT_FILTER_FS		0x06	/* Apply rule at __audit_inode_child */
+#define AUDIT_FILTER_URING_EXIT	0x07	/* Apply rule at io_uring op exit */
 
-#define AUDIT_NR_FILTERS	7
+#define AUDIT_NR_FILTERS	8
 
 #define AUDIT_FILTER_PREPEND	0x10	/* Prepend to front of list */
 
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index db2c6b59dfc3..c21119c00504 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -44,7 +44,8 @@ struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
 	LIST_HEAD_INIT(audit_filter_list[4]),
 	LIST_HEAD_INIT(audit_filter_list[5]),
 	LIST_HEAD_INIT(audit_filter_list[6]),
-#if AUDIT_NR_FILTERS != 7
+	LIST_HEAD_INIT(audit_filter_list[7]),
+#if AUDIT_NR_FILTERS != 8
 #error Fix audit_filter_list initialiser
 #endif
 };
@@ -56,6 +57,7 @@ static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
 	LIST_HEAD_INIT(audit_rules_list[4]),
 	LIST_HEAD_INIT(audit_rules_list[5]),
 	LIST_HEAD_INIT(audit_rules_list[6]),
+	LIST_HEAD_INIT(audit_rules_list[7]),
 };
 
 DEFINE_MUTEX(audit_filter_mutex);
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index d8aa2c690bf9..4f6ab34020fb 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -799,6 +799,35 @@ static int audit_in_mask(const struct audit_krule *rule, unsigned long val)
 	return rule->mask[word] & bit;
 }
 
+/**
+ * audit_filter_uring - apply filters to an io_uring operation
+ * @tsk: associated task
+ * @ctx: audit context
+ */
+static void audit_filter_uring(struct task_struct *tsk,
+			       struct audit_context *ctx)
+{
+	struct audit_entry *e;
+	enum audit_state state;
+
+	if (auditd_test_task(tsk))
+		return;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_URING_EXIT],
+				list) {
+		if (audit_in_mask(&e->rule, ctx->uring_op) &&
+		    audit_filter_rules(tsk, &e->rule, ctx, NULL, &state,
+				       false)) {
+			rcu_read_unlock();
+			ctx->current_state = state;
+			return;
+		}
+	}
+	rcu_read_unlock();
+	return;
+}
+
 /* At syscall exit time, this filter is called if the audit_state is
  * not low enough that auditing cannot take place, but is also not
  * high enough that we already know we have to write an audit record
@@ -1754,7 +1783,7 @@ static void audit_log_exit(void)
  * __audit_free - free a per-task audit context
  * @tsk: task whose audit context block to free
  *
- * Called from copy_process and do_exit
+ * Called from copy_process, do_exit, and the io_uring code
  */
 void __audit_free(struct task_struct *tsk)
 {
@@ -1772,15 +1801,21 @@ void __audit_free(struct task_struct *tsk)
 	 * random task_struct that doesn't doesn't have any meaningful data we
 	 * need to log via audit_log_exit().
 	 */
-	if (tsk == current && !context->dummy &&
-	    context->context == AUDIT_CTX_SYSCALL) {
+	if (tsk == current && !context->dummy) {
 		context->return_valid = AUDITSC_INVALID;
 		context->return_code = 0;
-
-		audit_filter_syscall(tsk, context);
-		audit_filter_inodes(tsk, context);
-		if (context->current_state == AUDIT_RECORD_CONTEXT)
-			audit_log_exit();
+		if (context->context == AUDIT_CTX_SYSCALL) {
+			audit_filter_syscall(tsk, context);
+			audit_filter_inodes(tsk, context);
+			if (context->current_state == AUDIT_RECORD_CONTEXT)
+				audit_log_exit();
+		} else if (context->context == AUDIT_CTX_URING) {
+			/* TODO: verify this case is real and valid */
+			audit_filter_uring(tsk, context);
+			audit_filter_inodes(tsk, context);
+			if (context->current_state == AUDIT_RECORD_CONTEXT)
+				audit_log_uring(context);
+		}
 	}
 
 	audit_set_context(tsk, NULL);
@@ -1861,12 +1896,6 @@ void __audit_uring_exit(int success, long code)
 {
 	struct audit_context *ctx = audit_context();
 
-	/*
-	 * TODO: At some point we will likely want to filter on io_uring ops
-	 *       and other things similar to what we do for syscalls, but that
-	 *       is something for another day; just record what we can here.
-	 */
-
 	if (!ctx || ctx->dummy)
 		goto out;
 	if (ctx->context == AUDIT_CTX_SYSCALL) {
@@ -1891,6 +1920,8 @@ void __audit_uring_exit(int success, long code)
 		 * the behavior here.
 		 */
 		audit_filter_syscall(current, ctx);
+		if (ctx->current_state != AUDIT_RECORD_CONTEXT)
+			audit_filter_uring(current, ctx);
 		audit_filter_inodes(current, ctx);
 		if (ctx->current_state != AUDIT_RECORD_CONTEXT)
 			return;
@@ -1899,7 +1930,9 @@ void __audit_uring_exit(int success, long code)
 		return;
 	}
 #if 1
-	/* XXX - temporary hack to force record generation */
+	/* XXX - temporary hack to force record generation, we are leaving this
+	 *       enabled, but if you want to actually test the filtering you
+	 *       need to disable this #if/#endif block */
 	ctx->current_state = AUDIT_RECORD_CONTEXT;
 #endif
 
@@ -1907,6 +1940,8 @@ void __audit_uring_exit(int success, long code)
 	if (!list_empty(&ctx->killed_trees))
 		audit_kill_trees(ctx);
 
+	/* run through both filters to ensure we set the filterkey properly */
+	audit_filter_uring(current, ctx);
 	audit_filter_inodes(current, ctx);
 	if (ctx->current_state != AUDIT_RECORD_CONTEXT)
 		goto out;


WARNING: multiple messages have this Message-ID
From: Paul Moore <paul@paul-moore.com>
To: linux-security-module@vger.kernel.org, selinux@vger.kernel.org,
	linux-audit@redhat.com, io-uring@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	Kumar Kartikeya Dwivedi <memxor@gmail.com>,
	Jens Axboe <axboe@kernel.dk>,
	Alexander Viro <viro@zeniv.linux.org.uk>
Subject: [RFC PATCH 4/9] audit: add filtering for io_uring records
Date: Fri, 21 May 2021 17:50:06 -0400	[thread overview]
Message-ID: <162163380685.8379.17381053199011043757.stgit@sifl> (raw)
In-Reply-To: <162163367115.8379.8459012634106035341.stgit@sifl>

WARNING - This is a work in progress and should not be merged
anywhere important.  It is almost surely not complete, and while it
probably compiles it likely hasn't been booted and will do terrible
things.  You have been warned.

This patch adds basic audit io_uring filtering, using as much of the
existing audit filtering infrastructure as possible.  In order to do
this we reuse the audit filter rule's syscall mask for the io_uring
operation and we create a new filter for io_uring operations as
AUDIT_FILTER_URING_EXIT/audit_filter_list[7].

<TODO - provide some additional guidance for the userspace tools>

Signed-off-by: Paul Moore <paul@paul-moore.com>
---
 include/uapi/linux/audit.h |    3 +-
 kernel/auditfilter.c       |    4 ++-
 kernel/auditsc.c           |   65 ++++++++++++++++++++++++++++++++++----------
 3 files changed, 55 insertions(+), 17 deletions(-)

diff --git a/include/uapi/linux/audit.h b/include/uapi/linux/audit.h
index b26e0c435e8b..621eb3c1076e 100644
--- a/include/uapi/linux/audit.h
+++ b/include/uapi/linux/audit.h
@@ -167,8 +167,9 @@
 #define AUDIT_FILTER_EXCLUDE	0x05	/* Apply rule before record creation */
 #define AUDIT_FILTER_TYPE	AUDIT_FILTER_EXCLUDE /* obsolete misleading naming */
 #define AUDIT_FILTER_FS		0x06	/* Apply rule at __audit_inode_child */
+#define AUDIT_FILTER_URING_EXIT	0x07	/* Apply rule at io_uring op exit */
 
-#define AUDIT_NR_FILTERS	7
+#define AUDIT_NR_FILTERS	8
 
 #define AUDIT_FILTER_PREPEND	0x10	/* Prepend to front of list */
 
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index db2c6b59dfc3..c21119c00504 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -44,7 +44,8 @@ struct list_head audit_filter_list[AUDIT_NR_FILTERS] = {
 	LIST_HEAD_INIT(audit_filter_list[4]),
 	LIST_HEAD_INIT(audit_filter_list[5]),
 	LIST_HEAD_INIT(audit_filter_list[6]),
-#if AUDIT_NR_FILTERS != 7
+	LIST_HEAD_INIT(audit_filter_list[7]),
+#if AUDIT_NR_FILTERS != 8
 #error Fix audit_filter_list initialiser
 #endif
 };
@@ -56,6 +57,7 @@ static struct list_head audit_rules_list[AUDIT_NR_FILTERS] = {
 	LIST_HEAD_INIT(audit_rules_list[4]),
 	LIST_HEAD_INIT(audit_rules_list[5]),
 	LIST_HEAD_INIT(audit_rules_list[6]),
+	LIST_HEAD_INIT(audit_rules_list[7]),
 };
 
 DEFINE_MUTEX(audit_filter_mutex);
diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index d8aa2c690bf9..4f6ab34020fb 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -799,6 +799,35 @@ static int audit_in_mask(const struct audit_krule *rule, unsigned long val)
 	return rule->mask[word] & bit;
 }
 
+/**
+ * audit_filter_uring - apply filters to an io_uring operation
+ * @tsk: associated task
+ * @ctx: audit context
+ */
+static void audit_filter_uring(struct task_struct *tsk,
+			       struct audit_context *ctx)
+{
+	struct audit_entry *e;
+	enum audit_state state;
+
+	if (auditd_test_task(tsk))
+		return;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(e, &audit_filter_list[AUDIT_FILTER_URING_EXIT],
+				list) {
+		if (audit_in_mask(&e->rule, ctx->uring_op) &&
+		    audit_filter_rules(tsk, &e->rule, ctx, NULL, &state,
+				       false)) {
+			rcu_read_unlock();
+			ctx->current_state = state;
+			return;
+		}
+	}
+	rcu_read_unlock();
+	return;
+}
+
 /* At syscall exit time, this filter is called if the audit_state is
  * not low enough that auditing cannot take place, but is also not
  * high enough that we already know we have to write an audit record
@@ -1754,7 +1783,7 @@ static void audit_log_exit(void)
  * __audit_free - free a per-task audit context
  * @tsk: task whose audit context block to free
  *
- * Called from copy_process and do_exit
+ * Called from copy_process, do_exit, and the io_uring code
  */
 void __audit_free(struct task_struct *tsk)
 {
@@ -1772,15 +1801,21 @@ void __audit_free(struct task_struct *tsk)
 	 * random task_struct that doesn't doesn't have any meaningful data we
 	 * need to log via audit_log_exit().
 	 */
-	if (tsk == current && !context->dummy &&
-	    context->context == AUDIT_CTX_SYSCALL) {
+	if (tsk == current && !context->dummy) {
 		context->return_valid = AUDITSC_INVALID;
 		context->return_code = 0;
-
-		audit_filter_syscall(tsk, context);
-		audit_filter_inodes(tsk, context);
-		if (context->current_state == AUDIT_RECORD_CONTEXT)
-			audit_log_exit();
+		if (context->context == AUDIT_CTX_SYSCALL) {
+			audit_filter_syscall(tsk, context);
+			audit_filter_inodes(tsk, context);
+			if (context->current_state == AUDIT_RECORD_CONTEXT)
+				audit_log_exit();
+		} else if (context->context == AUDIT_CTX_URING) {
+			/* TODO: verify this case is real and valid */
+			audit_filter_uring(tsk, context);
+			audit_filter_inodes(tsk, context);
+			if (context->current_state == AUDIT_RECORD_CONTEXT)
+				audit_log_uring(context);
+		}
 	}
 
 	audit_set_context(tsk, NULL);
@@ -1861,12 +1896,6 @@ void __audit_uring_exit(int success, long code)
 {
 	struct audit_context *ctx = audit_context();
 
-	/*
-	 * TODO: At some point we will likely want to filter on io_uring ops
-	 *       and other things similar to what we do for syscalls, but that
-	 *       is something for another day; just record what we can here.
-	 */
-
 	if (!ctx || ctx->dummy)
 		goto out;
 	if (ctx->context == AUDIT_CTX_SYSCALL) {
@@ -1891,6 +1920,8 @@ void __audit_uring_exit(int success, long code)
 		 * the behavior here.
 		 */
 		audit_filter_syscall(current, ctx);
+		if (ctx->current_state != AUDIT_RECORD_CONTEXT)
+			audit_filter_uring(current, ctx);
 		audit_filter_inodes(current, ctx);
 		if (ctx->current_state != AUDIT_RECORD_CONTEXT)
 			return;
@@ -1899,7 +1930,9 @@ void __audit_uring_exit(int success, long code)
 		return;
 	}
 #if 1
-	/* XXX - temporary hack to force record generation */
+	/* XXX - temporary hack to force record generation, we are leaving this
+	 *       enabled, but if you want to actually test the filtering you
+	 *       need to disable this #if/#endif block */
 	ctx->current_state = AUDIT_RECORD_CONTEXT;
 #endif
 
@@ -1907,6 +1940,8 @@ void __audit_uring_exit(int success, long code)
 	if (!list_empty(&ctx->killed_trees))
 		audit_kill_trees(ctx);
 
+	/* run through both filters to ensure we set the filterkey properly */
+	audit_filter_uring(current, ctx);
 	audit_filter_inodes(current, ctx);
 	if (ctx->current_state != AUDIT_RECORD_CONTEXT)
 		goto out;

--
Linux-audit mailing list
Linux-audit@redhat.com
https://listman.redhat.com/mailman/listinfo/linux-audit


  parent reply	other threads:[~2021-05-21 21:50 UTC|newest]

Thread overview: 142+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-21 21:49 [RFC PATCH 0/9] Add LSM access controls and auditing to io_uring Paul Moore
2021-05-21 21:49 ` [RFC PATCH 1/9] audit: prepare audit_context for use in calling contexts beyond syscalls Paul Moore
2021-05-21 21:49 ` [RFC PATCH 2/9] audit, io_uring, io-wq: add some basic audit support to io_uring Paul Moore
2021-05-22  0:22   ` [RFC PATCH 2/9] audit,io_uring,io-wq: " Pavel Begunkov
2021-05-22  2:36     ` Paul Moore
2021-05-23 20:26       ` Pavel Begunkov
2021-05-24 19:59         ` Paul Moore
2021-05-25  8:27           ` Pavel Begunkov
2021-05-25 14:53             ` Paul Moore
2021-05-26  1:11           ` Jens Axboe
2021-05-26  2:04             ` Paul Moore
2021-05-26 10:19               ` Pavel Begunkov
2021-05-26 14:38                 ` Paul Moore
2021-05-26 15:11                   ` [RFC PATCH 2/9] audit, io_uring, io-wq: " Steve Grubb
2021-05-26 15:17                   ` [RFC PATCH 2/9] audit,io_uring,io-wq: " Stefan Metzmacher
2021-05-26 15:49                     ` Richard Guy Briggs
2021-05-26 17:22                       ` Jens Axboe
2021-05-27 17:27                         ` Richard Guy Briggs
2021-05-26 15:49                     ` Victor Stewart
2021-05-26 16:38                       ` Casey Schaufler
2021-05-26 17:15               ` Jens Axboe
2021-05-26 17:31                 ` Jens Axboe
2021-05-26 17:54                   ` Jens Axboe
2021-05-26 18:01                     ` Jens Axboe
2021-05-26 18:44                       ` Paul Moore
2021-05-26 18:57                         ` Pavel Begunkov
2021-05-26 19:10                           ` Paul Moore
2021-05-26 19:44                         ` Jens Axboe
2021-05-26 20:19                           ` Paul Moore
2021-05-28 16:02                             ` Paul Moore
2021-06-02  8:26                               ` Pavel Begunkov
2021-06-02 15:46                                 ` Richard Guy Briggs
2021-06-03 10:39                                   ` Pavel Begunkov
2021-06-02 19:46                                 ` Paul Moore
2021-06-03 10:51                                   ` Pavel Begunkov
2021-06-03 15:54                                     ` Casey Schaufler
2021-06-03 15:54                               ` Jens Axboe
2021-06-04  5:04                                 ` Paul Moore
2021-05-26 18:38                     ` Paul Moore
2021-06-02 17:29   ` [RFC PATCH 2/9] audit, io_uring, io-wq: " Richard Guy Briggs
2021-06-02 20:46     ` Paul Moore
2021-08-25  1:21       ` Richard Guy Briggs
2021-08-25 19:41         ` Paul Moore
2021-05-21 21:50 ` [RFC PATCH 3/9] audit: dev/test patch to force io_uring auditing Paul Moore
2021-05-21 21:50 ` Paul Moore [this message]
2021-05-28 22:35   ` [RFC PATCH 4/9] audit: add filtering for io_uring records Richard Guy Briggs
2021-05-30 15:26     ` Paul Moore
2021-05-31 13:44       ` Richard Guy Briggs
2021-06-02  1:40         ` Paul Moore
2021-06-02 15:37           ` Richard Guy Briggs
2021-06-02 17:20             ` Paul Moore
2021-05-31 13:44       ` [PATCH 1/2] audit: add filtering for io_uring records, addendum Richard Guy Briggs
2021-05-31 16:08         ` kernel test robot
2021-05-31 17:38         ` kernel test robot
2021-06-07 23:15         ` Paul Moore
2021-06-08 12:55           ` Richard Guy Briggs
2021-06-09  2:45             ` Paul Moore
2021-05-31 13:44       ` [PATCH 2/2] audit: block PERM fields being used with io_uring filtering Richard Guy Briggs
2021-05-21 21:50 ` [RFC PATCH 5/9] fs: add anon_inode_getfile_secure() similar to anon_inode_getfd_secure() Paul Moore
2021-05-21 21:50 ` [RFC PATCH 6/9] io_uring: convert io_uring to the secure anon inode interface Paul Moore
2021-05-21 21:50 ` [RFC PATCH 7/9] lsm,io_uring: add LSM hooks to io_uring Paul Moore
2021-05-26 14:48   ` Stefan Metzmacher
2021-05-26 20:45     ` Paul Moore
2021-05-21 21:50 ` [RFC PATCH 8/9] selinux: add support for the io_uring access controls Paul Moore
2021-05-21 21:50 ` [RFC PATCH 9/9] Smack: Brutalist io_uring support with debug Paul Moore
2021-05-22  0:53 ` [RFC PATCH 0/9] Add LSM access controls and auditing to io_uring Tetsuo Handa
2021-05-22  2:06   ` Paul Moore
2021-05-26 15:00 ` Jeff Moyer
2021-05-26 18:49   ` Paul Moore
2021-05-26 19:07     ` Jeff Moyer
2021-05-26 19:10       ` Paul Moore

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