5.15-stable review patch. If anyone has any objections, please let me know.
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From: Steven Rostedt rostedt@goodmis.org
commit 917110481f6bc1c96b1e54b62bb114137fbc6d17 upstream.
The process_pointer() helper function looks to see if various trace event macros are used. These macros are for storing data in the event. This makes it safe to dereference as the dereference will then point into the event on the ring buffer where the content of the data stays with the event itself.
A few helper functions were missing. Those were:
__get_rel_dynamic_array() __get_dynamic_array_len() __get_rel_dynamic_array_len() __get_rel_sockaddr()
Also add a helper function find_print_string() to not need to use a middle man variable to test if the string exists.
Cc: stable@vger.kernel.org Cc: Masami Hiramatsu mhiramat@kernel.org Cc: Mark Rutland mark.rutland@arm.com Cc: Mathieu Desnoyers mathieu.desnoyers@efficios.com Cc: Andrew Morton akpm@linux-foundation.org Cc: Al Viro viro@ZenIV.linux.org.uk Cc: Linus Torvalds torvalds@linux-foundation.org Link: https://lore.kernel.org/20241217024720.521836792@goodmis.org Fixes: 5013f454a352c ("tracing: Add check of trace event print fmts for dereferencing pointers") Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/trace/trace_events.c | 21 +++++++++++++++++++-- 1 file changed, 19 insertions(+), 2 deletions(-)
--- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -257,6 +257,15 @@ static bool test_field(const char *fmt, return false; }
+/* Look for a string within an argument */ +static bool find_print_string(const char *arg, const char *str, const char *end) +{ + const char *r; + + r = strstr(arg, str); + return r && r < end; +} + /* Return true if the argument pointer is safe */ static bool process_pointer(const char *fmt, int len, struct trace_event_call *call) { @@ -275,9 +284,17 @@ static bool process_pointer(const char * a = strchr(fmt, '&'); if ((a && (a < r)) || test_field(r, call)) return true; - } else if ((r = strstr(fmt, "__get_dynamic_array(")) && r < e) { + } else if (find_print_string(fmt, "__get_dynamic_array(", e)) { + return true; + } else if (find_print_string(fmt, "__get_rel_dynamic_array(", e)) { + return true; + } else if (find_print_string(fmt, "__get_dynamic_array_len(", e)) { + return true; + } else if (find_print_string(fmt, "__get_rel_dynamic_array_len(", e)) { + return true; + } else if (find_print_string(fmt, "__get_sockaddr(", e)) { return true; - } else if ((r = strstr(fmt, "__get_sockaddr(")) && r < e) { + } else if (find_print_string(fmt, "__get_rel_sockaddr(", e)) { return true; } return false;