tracing: Use strlcpy() instead of strcpy() in __trace_find_cmdline()

commit e09e2867 upstream.

Strcpy is inherently not safe, and strlcpy() should be used instead.
__trace_find_cmdline() uses strcpy() because the comms saved must have a
terminating nul character, but it doesn't hurt to add the extra protection
of using strlcpy() instead of strcpy().

Link: http://lkml.kernel.org/r/1493806274-13936-1-git-send-email-amit.pundir@linaro.orgSigned-off-by: Amey Telawane <ameyt@codeaurora.org>
[AmitP: Cherry-picked this commit from CodeAurora kernel/msm-3.10
https://source.codeaurora.org/quic/la/kernel/msm-3.10/commit/?id=2161ae9a70b12cf18ac8e5952a20161ffbccb477]
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
[ Updated change log and removed the "- 1" from len parameter ]
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

kernel/trace/trace.c

@@ -1100,7 +1100,7 @@ void trace_find_cmdline(int pid, char comm[])
 	arch_spin_lock(&trace_cmdline_lock);
 	map = map_pid_to_cmdline[pid];
 	if (map != NO_CMDLINE_MAP)
-		strcpy(comm, saved_cmdlines[map]);
+		strlcpy(comm, saved_cmdlines[map], TASK_COMM_LEN);
 	else
 		strcpy(comm, "<...>");