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authorLinus Torvalds <torvalds@linux-foundation.org>2022-03-26 14:54:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-03-26 14:54:41 -0700
commitf022814633e1c600507b3a99691b4d624c2813f0 (patch)
tree8bb10067a8777133c9ad86c2ef38a4b1dada607f /kernel
parent710f5d627a98e86f821aceb840b8f2f1fcc6cf75 (diff)
parenteca344a7362e0f34f179298fd8366bcd556eede1 (diff)
downloadlinux-f022814633e1c600507b3a99691b4d624c2813f0.tar.bz2
Merge tag 'trace-v5.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull trace event string verifier fix from Steven Rostedt: "The run-time string verifier checks all trace event formats as they are read from the tracing file to make sure that the %s pointers are not reading something that no longer exists. However, it failed to account for the valid case of '%*.s' where the length given is zero, and the string is NULL. It incorrectly flagged it as a null pointer dereference and gave a WARN_ON()" * tag 'trace-v5.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: tracing: Have trace event string test handle zero length strings
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 08ea781540b5..f4de111fa18f 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -3673,12 +3673,17 @@ static char *trace_iter_expand_format(struct trace_iterator *iter)
}
/* Returns true if the string is safe to dereference from an event */
-static bool trace_safe_str(struct trace_iterator *iter, const char *str)
+static bool trace_safe_str(struct trace_iterator *iter, const char *str,
+ bool star, int len)
{
unsigned long addr = (unsigned long)str;
struct trace_event *trace_event;
struct trace_event_call *event;
+ /* Ignore strings with no length */
+ if (star && !len)
+ return true;
+
/* OK if part of the event data */
if ((addr >= (unsigned long)iter->ent) &&
(addr < (unsigned long)iter->ent + iter->ent_size))
@@ -3864,7 +3869,7 @@ void trace_check_vprintf(struct trace_iterator *iter, const char *fmt,
* instead. See samples/trace_events/trace-events-sample.h
* for reference.
*/
- if (WARN_ONCE(!trace_safe_str(iter, str),
+ if (WARN_ONCE(!trace_safe_str(iter, str, star, len),
"fmt: '%s' current_buffer: '%s'",
fmt, show_buffer(&iter->seq))) {
int ret;