diff options
| author | Stefan Hajnoczi <stefanha@redhat.com> | 2019-03-21 17:08:30 +0000 |
|---|---|---|
| committer | Stefan Hajnoczi <stefanha@redhat.com> | 2019-03-22 15:55:50 +0000 |
| commit | fd9858317a3d06c94ad8c1c420e6b5c376f5a92e (patch) | |
| tree | c87f18f18631f5c5bdcd999cda694e9458dc74e1 /trace | |
| parent | d97a39d903fe33c45be83ac6943a2f82a3649a11 (diff) | |
trace: handle tracefs path truncation
If the tracefs mountpoint has a very long path we may exceed PATH_MAX.
This is a system misconfiguration and the user must resolve it so that
applications can perform path-based system calls successfully.
This issue does not occur on real-world systems since tracefs is mounted
on /sys/kernel/debug/tracing/, but the compiler is smart enough to
foresee the possibility and warn about the unchecked snprintf(3) return
value. This patch fixes the compiler warning.
Reported-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Message-id: 20190321170831.6539-2-stefanha@redhat.com
Message-Id: <20190321170831.6539-2-stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'trace')
| -rw-r--r-- | trace/ftrace.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/trace/ftrace.c b/trace/ftrace.c index 61692a8682..9749543d9b 100644 --- a/trace/ftrace.c +++ b/trace/ftrace.c @@ -53,7 +53,11 @@ bool ftrace_init(void) } if (tracefs_found) { - snprintf(path, PATH_MAX, "%s%s/tracing_on", mount_point, subdir); + if (snprintf(path, PATH_MAX, "%s%s/tracing_on", mount_point, subdir) + >= sizeof(path)) { + fprintf(stderr, "Using tracefs mountpoint would exceed PATH_MAX\n"); + return false; + } trace_fd = open(path, O_WRONLY); if (trace_fd < 0) { if (errno == EACCES) { @@ -72,7 +76,11 @@ bool ftrace_init(void) } close(trace_fd); } - snprintf(path, PATH_MAX, "%s%s/trace_marker", mount_point, subdir); + if (snprintf(path, PATH_MAX, "%s%s/trace_marker", mount_point, subdir) + >= sizeof(path)) { + fprintf(stderr, "Using tracefs mountpoint would exceed PATH_MAX\n"); + return false; + } trace_marker_fd = open(path, O_WRONLY); if (trace_marker_fd < 0) { perror("Could not open ftrace 'trace_marker' file"); |