io_uring/io-wq: protect against sprintf overflow

task_pid may be large enough to not fit into the left space of
TASK_COMM_LEN-sized buffers and overflow in sprintf. We not so care
about uniqueness, so replace it with safer snprintf().

Reported-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/1702c6145d7e1c46fbc382f28334c02e1a3d3994.1617267273.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io-wq.c b/fs/io-wq.c
index 7434eb4..433c4d3 100644 (file)
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -484,7 +484,7 @@ static int io_wqe_worker(void *data)
        worker->flags |= (IO_WORKER_F_UP | IO_WORKER_F_RUNNING);
        io_wqe_inc_running(worker);
 
-       sprintf(buf, "iou-wrk-%d", wq->task_pid);
+       snprintf(buf, sizeof(buf), "iou-wrk-%d", wq->task_pid);
        set_task_comm(current, buf);
 
        while (!test_bit(IO_WQ_BIT_EXIT, &wq->state)) {
@@ -711,7 +711,7 @@ static int io_wq_manager(void *data)
        char buf[TASK_COMM_LEN];
        int node;
 
-       sprintf(buf, "iou-mgr-%d", wq->task_pid);
+       snprintf(buf, sizeof(buf), "iou-mgr-%d", wq->task_pid);
        set_task_comm(current, buf);
 
        do {

diff --git a/fs/io_uring.c b/fs/io_uring.c
index a16b7df..4a6701b 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -6718,7 +6718,7 @@ static int io_sq_thread(void *data)
        char buf[TASK_COMM_LEN];
        DEFINE_WAIT(wait);
 
-       sprintf(buf, "iou-sqp-%d", sqd->task_pid);
+       snprintf(buf, sizeof(buf), "iou-sqp-%d", sqd->task_pid);
        set_task_comm(current, buf);
        current->pf_io_worker = NULL;