From 696ee88a7c50f96573f98aa76cc74286033140c1 Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@gmail.com>
Date: Thu, 1 Apr 2021 09:55:04 +0100
Subject: [PATCH] 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>
---
fs/io-wq.c | 4 ++--
fs/io_uring.c | 2 +-
2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 7434eb40ca8ccb..433c4d3c3c1c8c 100644
--- 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 a16b7df934d149..4a6701b5065e27 100644
--- 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;
--
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