[PATCH 3.4-stable 1/2] tracing: Fix possible NULL pointer dereferences

[PATCH 3.4-stable 1/2] tracing: Fix possible NULL pointer dereferences

[Li Zefan]

commit 6a76f8c0ab19f215af2a3442870eeb5f0e81998d upstream.

Currently set_ftrace_pid and set_graph_function files use seq_lseek
for their fops.  However seq_open() is called only for FMODE_READ in
the fops->open() so that if an user tries to seek one of those file
when she open it for writing, it sees NULL seq_file and then panic.

It can be easily reproduced with following command:

  $ cd /sys/kernel/debug/tracing
  $ echo 1234 | sudo tee -a set_ftrace_pid

In this example, GNU coreutils' tee opens the file with fopen(, "a")
and then the fopen() internally calls lseek().

Link:
http://lkml.kernel.org/r/1365663302-2170-1-git-send-email-namhyung@kernel.org

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
[ lizf: adjust context ]
Signed-off-by: Li Zefan <lizefan@huawei.com>
---
 include/linux/ftrace.h     |  2 +-
 kernel/trace/ftrace.c      | 10 +++++-----
 kernel/trace/trace_stack.c |  2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 72a6cab..8add291 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -299,7 +299,7 @@ ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 			    size_t cnt, loff_t *ppos);
 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 			     size_t cnt, loff_t *ppos);
-loff_t ftrace_regex_lseek(struct file *file, loff_t offset, int origin);
+loff_t ftrace_filter_lseek(struct file *file, loff_t offset, int origin);
 int ftrace_regex_release(struct inode *inode, struct file *file);
 
 void __init
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index c962d31..8f74f42 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2626,7 +2626,7 @@ ftrace_notrace_open(struct inode *inode, struct file *file)
 }
 
 loff_t
-ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
+ftrace_filter_lseek(struct file *file, loff_t offset, int origin)
 {
 	loff_t ret;
 
@@ -3445,7 +3445,7 @@ static const struct file_operations ftrace_filter_fops = {
 	.open = ftrace_filter_open,
 	.read = seq_read,
 	.write = ftrace_filter_write,
-	.llseek = ftrace_regex_lseek,
+	.llseek = ftrace_filter_lseek,
 	.release = ftrace_regex_release,
 };
 
@@ -3453,7 +3453,7 @@ static const struct file_operations ftrace_notrace_fops = {
 	.open = ftrace_notrace_open,
 	.read = seq_read,
 	.write = ftrace_notrace_write,
-	.llseek = ftrace_regex_lseek,
+	.llseek = ftrace_filter_lseek,
 	.release = ftrace_regex_release,
 };
 
@@ -3659,8 +3659,8 @@ static const struct file_operations ftrace_graph_fops = {
 	.open		= ftrace_graph_open,
 	.read		= seq_read,
 	.write		= ftrace_graph_write,
+	.llseek		= ftrace_filter_lseek,
 	.release	= ftrace_graph_release,
-	.llseek		= seq_lseek,
 };
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
@@ -4261,7 +4261,7 @@ static const struct file_operations ftrace_pid_fops = {
 	.open		= ftrace_pid_open,
 	.write		= ftrace_pid_write,
 	.read		= seq_read,
-	.llseek		= seq_lseek,
+	.llseek		= ftrace_filter_lseek,
 	.release	= ftrace_pid_release,
 };
 
diff --git a/kernel/trace/trace_stack.c b/kernel/trace/trace_stack.c
index c70f6bf..8298997 100644
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -384,7 +384,7 @@ static const struct file_operations stack_trace_filter_fops = {
 	.open = stack_trace_filter_open,
 	.read = seq_read,
 	.write = ftrace_filter_write,
-	.llseek = ftrace_regex_lseek,
+	.llseek = ftrace_filter_lseek,
 	.release = ftrace_regex_release,
 };
 
-- 
1.8.0.2

[PATCH 3.4-stable 2/2] ftrace: Move ftrace_filter_lseek out of CONFIG_DYNAMIC_FTRACE section

[Li Zefan]

commit 7f49ef69db6bbf756c0abca7e9b65b32e999eec8 upstream.

As ftrace_filter_lseek is now used with ftrace_pid_fops, it needs to
be moved out of the #ifdef CONFIG_DYNAMIC_FTRACE section as the
ftrace_pid_fops is defined when DYNAMIC_FTRACE is not.

Cc: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
[ lizf: adjust context ]
Signed-off-by: Li Zefan <lizefan@huawei.com>
---
 include/linux/ftrace.h |  3 ++-
 kernel/trace/ftrace.c  | 28 ++++++++++++++--------------
 2 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 8add291..f80ca4a 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -299,7 +299,6 @@ ssize_t ftrace_filter_write(struct file *file, const char __user *ubuf,
 			    size_t cnt, loff_t *ppos);
 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 			     size_t cnt, loff_t *ppos);
-loff_t ftrace_filter_lseek(struct file *file, loff_t offset, int origin);
 int ftrace_regex_release(struct inode *inode, struct file *file);
 
 void __init
@@ -420,6 +419,8 @@ static inline int
 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
+loff_t ftrace_filter_lseek(struct file *file, loff_t offset, int whence);
+
 /* totally disable ftrace - can not re-enable after this */
 void ftrace_kill(void);
 
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 8f74f42..e101cf9 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -999,6 +999,19 @@ static __init void ftrace_profile_debugfs(struct dentry *d_tracer)
 
 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
 
+loff_t
+ftrace_filter_lseek(struct file *file, loff_t offset, int whence)
+{
+	loff_t ret;
+
+	if (file->f_mode & FMODE_READ)
+		ret = seq_lseek(file, offset, whence);
+	else
+		file->f_pos = ret = 1;
+
+	return ret;
+}
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 
 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
@@ -2541,7 +2554,7 @@ static void ftrace_filter_reset(struct ftrace_hash *hash)
  * routine, you can use ftrace_filter_write() for the write
  * routine if @flag has FTRACE_ITER_FILTER set, or
  * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
- * ftrace_regex_lseek() should be used as the lseek routine, and
+ * ftrace_filter_lseek() should be used as the lseek routine, and
  * release must call ftrace_regex_release().
  */
 int
@@ -2625,19 +2638,6 @@ ftrace_notrace_open(struct inode *inode, struct file *file)
 				 inode, file);
 }
 
-loff_t
-ftrace_filter_lseek(struct file *file, loff_t offset, int origin)
-{
-	loff_t ret;
-
-	if (file->f_mode & FMODE_READ)
-		ret = seq_lseek(file, offset, origin);
-	else
-		file->f_pos = ret = 1;
-
-	return ret;
-}
-
 static int ftrace_match(char *str, char *regex, int len, int type)
 {
 	int matched = 0;
-- 
1.8.0.2

Patch "tracing: Fix possible NULL pointer dereferences" has been added to the 3.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    tracing: Fix possible NULL pointer dereferences

to the 3.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     tracing-fix-possible-null-pointer-dereferences.patch
and it can be found in the queue-3.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From lizefan@huawei.com  Mon Jun 10 14:15:28 2013
From: Namhyung Kim <namhyung.kim@lge.com>
Date: Fri, 7 Jun 2013 17:01:16 +0800
Subject: tracing: Fix possible NULL pointer dereferences
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>, Steven Rostedt <rostedt@goodmis.org>, Frederic Weisbecker <fweisbec@gmail.com>, Ingo Molnar <mingo@kernel.org>, LKML <linux-kernel@vger.kernel.org>, stable <stable@vger.kernel.org>
Message-ID: <51B1A15C.5040108@huawei.com>


From: Namhyung Kim <namhyung.kim@lge.com>

commit 6a76f8c0ab19f215af2a3442870eeb5f0e81998d upstream.

Currently set_ftrace_pid and set_graph_function files use seq_lseek
for their fops.  However seq_open() is called only for FMODE_READ in
the fops->open() so that if an user tries to seek one of those file
when she open it for writing, it sees NULL seq_file and then panic.

It can be easily reproduced with following command:

  $ cd /sys/kernel/debug/tracing
  $ echo 1234 | sudo tee -a set_ftrace_pid

In this example, GNU coreutils' tee opens the file with fopen(, "a")
and then the fopen() internally calls lseek().

Link:
http://lkml.kernel.org/r/1365663302-2170-1-git-send-email-namhyung@kernel.org

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
[ lizf: adjust context ]
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/ftrace.h     |    2 +-
 kernel/trace/ftrace.c      |   10 +++++-----
 kernel/trace/trace_stack.c |    2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -299,7 +299,7 @@ ssize_t ftrace_filter_write(struct file
 			    size_t cnt, loff_t *ppos);
 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 			     size_t cnt, loff_t *ppos);
-loff_t ftrace_regex_lseek(struct file *file, loff_t offset, int origin);
+loff_t ftrace_filter_lseek(struct file *file, loff_t offset, int origin);
 int ftrace_regex_release(struct inode *inode, struct file *file);
 
 void __init
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -2626,7 +2626,7 @@ ftrace_notrace_open(struct inode *inode,
 }
 
 loff_t
-ftrace_regex_lseek(struct file *file, loff_t offset, int origin)
+ftrace_filter_lseek(struct file *file, loff_t offset, int origin)
 {
 	loff_t ret;
 
@@ -3445,7 +3445,7 @@ static const struct file_operations ftra
 	.open = ftrace_filter_open,
 	.read = seq_read,
 	.write = ftrace_filter_write,
-	.llseek = ftrace_regex_lseek,
+	.llseek = ftrace_filter_lseek,
 	.release = ftrace_regex_release,
 };
 
@@ -3453,7 +3453,7 @@ static const struct file_operations ftra
 	.open = ftrace_notrace_open,
 	.read = seq_read,
 	.write = ftrace_notrace_write,
-	.llseek = ftrace_regex_lseek,
+	.llseek = ftrace_filter_lseek,
 	.release = ftrace_regex_release,
 };
 
@@ -3659,8 +3659,8 @@ static const struct file_operations ftra
 	.open		= ftrace_graph_open,
 	.read		= seq_read,
 	.write		= ftrace_graph_write,
+	.llseek		= ftrace_filter_lseek,
 	.release	= ftrace_graph_release,
-	.llseek		= seq_lseek,
 };
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
@@ -4261,7 +4261,7 @@ static const struct file_operations ftra
 	.open		= ftrace_pid_open,
 	.write		= ftrace_pid_write,
 	.read		= seq_read,
-	.llseek		= seq_lseek,
+	.llseek		= ftrace_filter_lseek,
 	.release	= ftrace_pid_release,
 };
 
--- a/kernel/trace/trace_stack.c
+++ b/kernel/trace/trace_stack.c
@@ -384,7 +384,7 @@ static const struct file_operations stac
 	.open = stack_trace_filter_open,
 	.read = seq_read,
 	.write = ftrace_filter_write,
-	.llseek = ftrace_regex_lseek,
+	.llseek = ftrace_filter_lseek,
 	.release = ftrace_regex_release,
 };
 


Patches currently in stable-queue which might be from namhyung.kim@lge.com are

queue-3.4/tracing-fix-possible-null-pointer-dereferences.patch

Patch "ftrace: Move ftrace_filter_lseek out of CONFIG_DYNAMIC_FTRACE section" has been added to the 3.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    ftrace: Move ftrace_filter_lseek out of CONFIG_DYNAMIC_FTRACE section

to the 3.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ftrace-move-ftrace_filter_lseek-out-of-config_dynamic_ftrace-section.patch
and it can be found in the queue-3.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From lizefan@huawei.com  Mon Jun 10 14:15:51 2013
From: Li Zefan <lizefan@huawei.com>
Date: Fri, 7 Jun 2013 17:02:08 +0800
Subject: ftrace: Move ftrace_filter_lseek out of CONFIG_DYNAMIC_FTRACE section
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>, Steven Rostedt <rostedt@goodmis.org>, Frederic Weisbecker <fweisbec@gmail.com>, Ingo Molnar <mingo@kernel.org>, LKML <linux-kernel@vger.kernel.org>, stable <stable@vger.kernel.org>
Message-ID: <51B1A190.4060409@huawei.com>


From: Steven Rostedt <rostedt@goodmis.org>

commit 7f49ef69db6bbf756c0abca7e9b65b32e999eec8 upstream.

As ftrace_filter_lseek is now used with ftrace_pid_fops, it needs to
be moved out of the #ifdef CONFIG_DYNAMIC_FTRACE section as the
ftrace_pid_fops is defined when DYNAMIC_FTRACE is not.

Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Namhyung Kim <namhyung@kernel.org>
[ lizf: adjust context ]
Signed-off-by: Li Zefan <lizefan@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/ftrace.h |    3 ++-
 kernel/trace/ftrace.c  |   28 ++++++++++++++--------------
 2 files changed, 16 insertions(+), 15 deletions(-)

--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -299,7 +299,6 @@ ssize_t ftrace_filter_write(struct file
 			    size_t cnt, loff_t *ppos);
 ssize_t ftrace_notrace_write(struct file *file, const char __user *ubuf,
 			     size_t cnt, loff_t *ppos);
-loff_t ftrace_filter_lseek(struct file *file, loff_t offset, int origin);
 int ftrace_regex_release(struct inode *inode, struct file *file);
 
 void __init
@@ -420,6 +419,8 @@ static inline int
 ftrace_regex_release(struct inode *inode, struct file *file) { return -ENODEV; }
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
+loff_t ftrace_filter_lseek(struct file *file, loff_t offset, int whence);
+
 /* totally disable ftrace - can not re-enable after this */
 void ftrace_kill(void);
 
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -999,6 +999,19 @@ static __init void ftrace_profile_debugf
 
 static struct pid * const ftrace_swapper_pid = &init_struct_pid;
 
+loff_t
+ftrace_filter_lseek(struct file *file, loff_t offset, int whence)
+{
+	loff_t ret;
+
+	if (file->f_mode & FMODE_READ)
+		ret = seq_lseek(file, offset, whence);
+	else
+		file->f_pos = ret = 1;
+
+	return ret;
+}
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 
 #ifndef CONFIG_FTRACE_MCOUNT_RECORD
@@ -2541,7 +2554,7 @@ static void ftrace_filter_reset(struct f
  * routine, you can use ftrace_filter_write() for the write
  * routine if @flag has FTRACE_ITER_FILTER set, or
  * ftrace_notrace_write() if @flag has FTRACE_ITER_NOTRACE set.
- * ftrace_regex_lseek() should be used as the lseek routine, and
+ * ftrace_filter_lseek() should be used as the lseek routine, and
  * release must call ftrace_regex_release().
  */
 int
@@ -2625,19 +2638,6 @@ ftrace_notrace_open(struct inode *inode,
 				 inode, file);
 }
 
-loff_t
-ftrace_filter_lseek(struct file *file, loff_t offset, int origin)
-{
-	loff_t ret;
-
-	if (file->f_mode & FMODE_READ)
-		ret = seq_lseek(file, offset, origin);
-	else
-		file->f_pos = ret = 1;
-
-	return ret;
-}
-
 static int ftrace_match(char *str, char *regex, int len, int type)
 {
 	int matched = 0;


Patches currently in stable-queue which might be from lizefan@huawei.com are

queue-3.4/tracing-fix-possible-null-pointer-dereferences.patch
queue-3.4/ftrace-move-ftrace_filter_lseek-out-of-config_dynamic_ftrace-section.patch