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authorNamhyung Kim <namhyung.kim@lge.com>2013-06-07 17:01:16 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-06-13 09:45:03 -0700
commit3a22cc7f184b77731816e55662cd12f0c3d24d56 (patch)
treece3612a4ea2ec1ed53d5c98a24b88aa80067129c
parentce840e2f7825bfd240782dc209c2f2b8db514287 (diff)
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tracing: Fix possible NULL pointer dereferences
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>
-rw-r--r--include/linux/ftrace.h2
-rw-r--r--kernel/trace/ftrace.c10
-rw-r--r--kernel/trace/trace_stack.c2
3 files changed, 7 insertions, 7 deletions
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 72a6cabb4d5..8add29129fb 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 c962d311c77..8f74f4255ff 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 c70f6bfbb73..8298997c248 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,
};