From: Tomas Bortoli tomasbortoli@gmail.com
commit dfb4a6f2191a80c8b790117d0ff592fd712d3296 upstream.
In case of errors, predicate_parse() goes to the out_free label to free memory and to return an error code.
However, predicate_parse() does not free the predicates of the temporary prog_stack array, thence leaking them.
Link: http://lkml.kernel.org/r/20190528154338.29976-1-tomasbortoli@gmail.com
Cc: stable@vger.kernel.org Fixes: 80765597bc587 ("tracing: Rewrite filter logic to be simpler and faster") Reported-by: syzbot+6b8e0fb820e570c59e19@syzkaller.appspotmail.com Signed-off-by: Tomas Bortoli tomasbortoli@gmail.com [ Added protection around freeing prog_stack[i].pred ] Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/trace/trace_events_filter.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/kernel/trace/trace_events_filter.c +++ b/kernel/trace/trace_events_filter.c @@ -427,7 +427,7 @@ predicate_parse(const char *str, int nr_ op_stack = kmalloc_array(nr_parens, sizeof(*op_stack), GFP_KERNEL); if (!op_stack) return ERR_PTR(-ENOMEM); - prog_stack = kmalloc_array(nr_preds, sizeof(*prog_stack), GFP_KERNEL); + prog_stack = kcalloc(nr_preds, sizeof(*prog_stack), GFP_KERNEL); if (!prog_stack) { parse_error(pe, -ENOMEM, 0); goto out_free; @@ -576,7 +576,11 @@ predicate_parse(const char *str, int nr_ out_free: kfree(op_stack); kfree(inverts); - kfree(prog_stack); + if (prog_stack) { + for (i = 0; prog_stack[i].pred; i++) + kfree(prog_stack[i].pred); + kfree(prog_stack); + } return ERR_PTR(ret); }