linux-kernel - [PATCH] io_uring: Fix memory leak in io_sqe_buffers

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Date:   Fri, 30 Apr 2021 16:25:15 +0800
From:   qiang.zhang@...driver.com
To:     axboe@...nel.dk, io-uring@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org
Subject: [PATCH] io_uring: Fix memory leak in io_sqe_buffers_register()

From: Zqiang <qiang.zhang@...driver.com>

unreferenced object 0xffff8881123bf0a0 (size 32):
comm "syz-executor557", pid 8384, jiffies 4294946143 (age 12.360s)
backtrace:
[<ffffffff81469b71>] kmalloc_node include/linux/slab.h:579 [inline]
[<ffffffff81469b71>] kvmalloc_node+0x61/0xf0 mm/util.c:587
[<ffffffff815f0b3f>] kvmalloc include/linux/mm.h:795 [inline]
[<ffffffff815f0b3f>] kvmalloc_array include/linux/mm.h:813 [inline]
[<ffffffff815f0b3f>] kvcalloc include/linux/mm.h:818 [inline]
[<ffffffff815f0b3f>] io_rsrc_data_alloc+0x4f/0xc0 fs/io_uring.c:7164
[<ffffffff815f26d8>] io_sqe_buffers_register+0x98/0x3d0 fs/io_uring.c:8383
[<ffffffff815f84a7>] __io_uring_register+0xf67/0x18c0 fs/io_uring.c:9986
[<ffffffff81609222>] __do_sys_io_uring_register fs/io_uring.c:10091 [inline]
[<ffffffff81609222>] __se_sys_io_uring_register fs/io_uring.c:10071 [inline]
[<ffffffff81609222>] __x64_sys_io_uring_register+0x112/0x230 fs/io_uring.c:10071
[<ffffffff842f616a>] do_syscall_64+0x3a/0xb0 arch/x86/entry/common.c:47
[<ffffffff84400068>] entry_SYSCALL_64_after_hwframe+0x44/0xae

Fix data->tags memory leak, through io_rsrc_data_free() to release
data memory space.

Reported-by: syzbot+0f32d05d8b6cd8d7ea3e@...kaller.appspotmail.com
Signed-off-by: Zqiang <qiang.zhang@...driver.com>
---
 fs/io_uring.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index a880edb90d0c..7a2e83bc005d 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8140,7 +8140,7 @@ static void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx)
 	for (i = 0; i < ctx->nr_user_bufs; i++)
 		io_buffer_unmap(ctx, &ctx->user_bufs[i]);
 	kfree(ctx->user_bufs);
-	kfree(ctx->buf_data);
+	io_rsrc_data_free(ctx->buf_data);
 	ctx->user_bufs = NULL;
 	ctx->buf_data = NULL;
 	ctx->nr_user_bufs = 0;
@@ -8400,7 +8400,7 @@ static int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg,
 		return -ENOMEM;
 	ret = io_buffers_map_alloc(ctx, nr_args);
 	if (ret) {
-		kfree(data);
+		io_rsrc_data_free(data);
 		return ret;
 	}
 
-- 
2.17.1