kernel/linux.git/io_uring/net.c, branch v6.12.81

io_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs()

2026-04-11T12:24:40+00:00

commit b948f9d5d3057b01188e36664e7c7604d1c8ecb5 upstream. sqe->len is __u32 but gets stored into sr->len which is int. When userspace passes sqe->len values exceeding INT_MAX (e.g. 0xFFFFFFFF), sr->len overflows to a negative value. This negative value propagates through the bundle recv/send path: 1. io_recv(): sel.val = sr->len (ssize_t gets -1) 2. io_recv_buf_select(): arg.max_len = sel->val (size_t gets 0xFFFFFFFFFFFFFFFF) 3. io_ring_buffers_peek(): buf->len is not clamped because max_len is astronomically large 4. iov[].iov_len = 0xFFFFFFFF flows into io_bundle_nbufs() 5. io_bundle_nbufs(): min_t(int, 0xFFFFFFFF, ret) yields -1, causing ret to increase instead of decrease, creating an infinite loop that reads past the allocated iov[] array This results in a slab-out-of-bounds read in io_bundle_nbufs() from the kmalloc-64 slab, as nbufs increments past the allocated iovec entries. BUG: KASAN: slab-out-of-bounds in io_bundle_nbufs+0x128/0x160 Read of size 8 at addr ffff888100ae05c8 by task exp/145 Call Trace: io_bundle_nbufs+0x128/0x160 io_recv_finish+0x117/0xe20 io_recv+0x2db/0x1160 Fix this by rejecting negative sr->len values early in both io_sendmsg_prep() and io_recvmsg_prep(). Since sqe->len is __u32, any value > INT_MAX indicates overflow and is not a valid length. Fixes: a05d1f625c7a ("io_uring/net: support bundles for send") Cc: stable@vger.kernel.org Signed-off-by: Junxi Qian Link: https://patch.msgid.link/20260329153909.279046-1-qjx1298677004@gmail.com Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/net: correct type for min_not_zero() cast

2026-04-11T12:24:27+00:00

Commit 37500634d0a8f931e15879760fb70f9b6f5d5370 upstream. The kernel test robot reports that after a recent change, the signedness of a min_not_zero() compare is now incorrect. Fix that up and cast to the right type. Fixes: 429884ff35f7 ("io_uring/kbuf: use struct io_br_sel for multiple buffers picking") Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202509020426.WJtrdwOU-lkp@intel.com/ Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/kbuf: switch to storing struct io_buffer_list locally

2026-04-11T12:24:27+00:00

Commit 5fda51255439addd1c9059098e30847a375a1008 upstream. Currently the buffer list is stored in struct io_kiocb. The buffer list can be of two types: 1) Classic/legacy buffer list. These don't need to get referenced after a buffer pick, and hence storing them in struct io_kiocb is perfectly fine. 2) Ring provided buffer lists. These DO need to be referenced after the initial buffer pick, as they need to get consumed later on. This can be either just incrementing the head of the ring, or it can be consuming parts of a buffer if incremental buffer consumptions has been configured. For case 2, io_uring needs to be careful not to access the buffer list after the initial pick-and-execute context. The core does recycling of these, but it's easy to make a mistake, because it's stored in the io_kiocb which does persist across multiple execution contexts. Either because it's a multishot request, or simply because it needed some kind of async trigger (eg poll) for retry purposes. Add a struct io_buffer_list to struct io_br_sel, which is always on stack for the various users of it. This prevents the buffer list from leaking outside of that execution context, and additionally it enables kbuf to not even pass back the struct io_buffer_list if the given context isn't appropriately locked already. This doesn't fix any bugs, it's simply a defensive measure to prevent any issues with reuse of a buffer list. Link: https://lore.kernel.org/r/20250821020750.598432-12-axboe@kernel.dk Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/net: use struct io_br_sel->val as the send finish value

2026-04-11T12:24:27+00:00

Commit 461382a51fb83a9c4b7c50e1f10d3ca94edff25e upstream. Currently a pointer is passed in to the 'ret' in the send mshot handler, but since we already have a value field in io_br_sel, just use that. This is also in preparation for needing to pass in struct io_br_sel to io_send_finish() anyway. Link: https://lore.kernel.org/r/20250821020750.598432-11-axboe@kernel.dk Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/net: use struct io_br_sel->val as the recv finish value

2026-04-11T12:24:27+00:00

Commit 58d815091890e83aa2f83a9cce1fdfe3af02c7b4 upstream. Currently a pointer is passed in to the 'ret' in the receive handlers, but since we already have a value field in io_br_sel, just use that. This is also in preparation for needing to pass in struct io_br_sel to io_recv_finish() anyway. Link: https://lore.kernel.org/r/20250821020750.598432-10-axboe@kernel.dk Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/kbuf: use struct io_br_sel for multiple buffers picking

2026-04-11T12:24:27+00:00

Commit 429884ff35f75a8ac3e8f822f483e220e3ea6394 upstream. The networking side uses bundles, which is picking multiple buffers at the same time. Pass in struct io_br_sel to those helpers. Link: https://lore.kernel.org/r/20250821020750.598432-9-axboe@kernel.dk Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/kbuf: introduce struct io_br_sel

2026-04-11T12:24:26+00:00

Commit ab6559bdbb08f6bee606435cd014fc5ba0f7b750 upstream. Rather than return addresses directly from buffer selection, add a struct around it. No functional changes in this patch, it's in preparation for storing more buffer related information locally, rather than in struct io_kiocb. Link: https://lore.kernel.org/r/20250821020750.598432-7-axboe@kernel.dk Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/kbuf: pass in struct io_buffer_list to commit/recycle helpers

2026-04-11T12:24:26+00:00

Commit 1b5add75d7c894c62506c9b55f1d9eaadae50ef1 upstream. Rather than have this implied being in the io_kiocb, pass it in directly so it's immediately obvious where these users of ->buf_list are coming from. Link: https://lore.kernel.org/r/20250821020750.598432-6-axboe@kernel.dk Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/net: clarify io_recv_buf_select() return value

2026-04-11T12:24:26+00:00

Commit b22743f29b7d3dc68c68f9bd39a1b2600ec6434e upstream. It returns 0 on success, less than zero on error. Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

io_uring/net: don't use io_net_kbuf_recyle() for non-provided cases

2026-04-11T12:24:26+00:00

Commit 15ba5e51e689ceb1c2e921c5180a70c88cfdc8e9 upstream. A previous commit used io_net_kbuf_recyle() for any network helper that did IO and needed partial retry. However, that's only needed if the opcode does buffer selection, which isnt support for sendzc, sendmsg_zc, or sendmsg. Just remove them - they don't do any harm, but it is a bit confusing when reading the code. Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman