user_events: Fix potential uninitialized pointer while parsing field

Ensure name is initialized by default to NULL to prevent possible edge
cases that could lead to it being left uninitialized. Add an explicit
check for NULL name to ensure edge boundaries.

Link: https://lore.kernel.org/bpf/20220224105334.GA2248@kili/
Link: https://lore.kernel.org/linux-trace-devel/20220224181637.2129-1-beaub@linux.microsoft.com
Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
index 2b5e9fd..9a6191a 100644 (file)
--- a/kernel/trace/trace_events_user.c
+++ b/kernel/trace/trace_events_user.c
@@ -362,6 +362,8 @@ skip_next:
        *field++ = '\0';
        depth++;
 parse:
+       name = NULL;
+
        while ((part = strsep(&field, " ")) != NULL) {
                switch (depth++) {
                case FIELD_DEPTH_TYPE:
@@ -382,7 +384,7 @@ parse:
                }
        }
 
-       if (depth < FIELD_DEPTH_SIZE)
+       if (depth < FIELD_DEPTH_SIZE || !name)
                return -EINVAL;
 
        if (depth == FIELD_DEPTH_SIZE)