Messages in this thread Patch in this message | | | From | Wang Long <> | Subject | [RFC PATCH 06/17] tracing: Use trace_seq_used() and seq_buf_used() instead of len | Date | Thu, 14 May 2015 11:34:53 +0000 |
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From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
commit 5ac48378414dccca735897c4d7f4e19987c8977c upstream.
As the seq_buf->len will soon be +1 size when there's an overflow, we must use trace_seq_used() or seq_buf_used() methods to get the real length. This will prevent buffer overflow issues if just the len of the seq_buf descriptor is used to copy memory.
Link: http://lkml.kernel.org/r/20141114121911.09ba3d38@gandalf.local.home
Reported-by: Petr Mladek <pmladek@suse.cz> [wanglong: backport to 3.10 stable - only backport seq_buf related ] Signed-off-by: Wang Long <long.wanglong@huawei.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- kernel/trace/seq_buf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/seq_buf.c b/kernel/trace/seq_buf.c index 9ec5305..ce17f65 100644 --- a/kernel/trace/seq_buf.c +++ b/kernel/trace/seq_buf.c @@ -328,7 +328,7 @@ int seq_buf_to_user(struct seq_buf *s, char __user *ubuf, int cnt) if (s->len <= s->readpos) return -EBUSY; - len = s->len - s->readpos; + len = seq_buf_used(s) - s->readpos; if (cnt > len) cnt = len; ret = copy_to_user(ubuf, s->buffer + s->readpos, cnt); -- 1.8.3.4
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