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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2026-08-09 06:14:34 +02:00
Vasileios AlmpanisandJens Axboe
2564ca2e31
NOP file-acquisition support choses between a fixed (registered) file and
a normal fget()'d file based on its own IORING_NOP_FIXED_FILE flag in
sqe->nop_flags. However, a request's REQ_F_FIXED_FILE is set
independently from the generic IOSQE_FIXED_FILE sqe flag during request
init, before the issue handler runs.
If a NOP is submitted with IOSQE_FIXED_FILE set (so REQ_F_FIXED_FILE is
set) but without IORING_NOP_FIXED_FILE, io_nop() takes the normal path
and grabs a real reference via io_file_get_normal(). On completion,
io_put_file() only drops the reference when REQ_F_FIXED_FILE is clear,
so the fget()'d file is never released and leaks:
BUG: memory leak
unreferenced object 0xffff88800f42c240 (size 176):
kmem_cache_alloc_noprof+0x358/0x440
alloc_empty_file+0x57/0x180
path_openat+0x44/0x1e50
do_file_open+0x121/0x200
do_sys_openat2+0xa7/0x150
__x64_sys_openat+0x82/0xf0
Decide between fixed and normal file acquisition from REQ_F_FIXED_FILE,
the same way io_assign_file() does for every other opcode, and fold
IORING_NOP_FIXED_FILE into REQ_F_FIXED_FILE at prep time.
Cc: stable@vger.kernel.org
Fixes: a85f31052b ("io_uring/nop: add support for testing registered files and buffers")
Reported-by: syzbot+2cd473471e77bda12b0e@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?id=879092631b98f73a28ea405adacfa5bb34a14a25
Signed-off-by: Vasileios Almpanis <vasilisalmpanis@gmail.com>
Link: https://patch.msgid.link/20260615144619.482749-1-vasilisalmpanis@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
91 lines
2.2 KiB
C
91 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/io_uring.h>
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#include <uapi/linux/io_uring.h>
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#include "io_uring.h"
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#include "rsrc.h"
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#include "nop.h"
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struct io_nop {
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struct file *file;
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int result;
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int fd;
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unsigned int flags;
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__u64 extra1;
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__u64 extra2;
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};
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#define NOP_FLAGS (IORING_NOP_INJECT_RESULT | IORING_NOP_FIXED_FILE | \
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IORING_NOP_FIXED_BUFFER | IORING_NOP_FILE | \
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IORING_NOP_TW | IORING_NOP_CQE32)
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int io_nop_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
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{
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struct io_nop *nop = io_kiocb_to_cmd(req, struct io_nop);
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nop->flags = READ_ONCE(sqe->nop_flags);
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if (nop->flags & ~NOP_FLAGS)
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return -EINVAL;
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if (nop->flags & IORING_NOP_INJECT_RESULT)
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nop->result = READ_ONCE(sqe->len);
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else
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nop->result = 0;
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if (nop->flags & IORING_NOP_FILE)
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nop->fd = READ_ONCE(sqe->fd);
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else
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nop->fd = -1;
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if (nop->flags & IORING_NOP_FIXED_FILE)
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req->flags |= REQ_F_FIXED_FILE;
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if (nop->flags & IORING_NOP_FIXED_BUFFER)
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req->buf_index = READ_ONCE(sqe->buf_index);
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if (nop->flags & IORING_NOP_CQE32) {
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struct io_ring_ctx *ctx = req->ctx;
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if (!(ctx->flags & (IORING_SETUP_CQE32|IORING_SETUP_CQE_MIXED)))
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return -EINVAL;
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nop->extra1 = READ_ONCE(sqe->off);
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nop->extra2 = READ_ONCE(sqe->addr);
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}
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return 0;
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}
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int io_nop(struct io_kiocb *req, unsigned int issue_flags)
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{
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struct io_nop *nop = io_kiocb_to_cmd(req, struct io_nop);
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int ret = nop->result;
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if (nop->flags & IORING_NOP_FILE) {
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if (req->flags & REQ_F_FIXED_FILE)
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req->file = io_file_get_fixed(req, nop->fd, issue_flags);
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else
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req->file = io_file_get_normal(req, nop->fd);
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if (!req->file) {
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ret = -EBADF;
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goto done;
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}
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}
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if (nop->flags & IORING_NOP_FIXED_BUFFER) {
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if (!io_find_buf_node(req, issue_flags))
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ret = -EFAULT;
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}
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done:
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if (ret < 0)
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req_set_fail(req);
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if (nop->flags & IORING_NOP_CQE32)
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io_req_set_res32(req, ret, 0, nop->extra1, nop->extra2);
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else
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io_req_set_res(req, ret, 0);
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if (nop->flags & IORING_NOP_TW) {
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req->io_task_work.func = io_req_task_complete;
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io_req_task_work_add(req);
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return IOU_ISSUE_SKIP_COMPLETE;
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}
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return IOU_COMPLETE;
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}
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