nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone

Summary

In the Linux kernel, the following vulnerability has been resolved: nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone Commit 25e5cb780e62 ("nvme-tcp: fix possible crash in write_zeroes processing") established that blk_rq_payload_bytes() must not be read without first checking blk_rq_nr_phys_segments(), and recorded the result in nvme_tcp_setup_cmd_pdu() as req->data_len. The receive side was left as it was. The two differ for REQ_OP_WRITE_ZEROES, which has no physical segments but a non-zero blk_rq_bytes(), so setup leaves req->iter untouched while the receive gate lets a C2HData through and nvme_tcp_recv_data() copies into whatever the previous command on that tag left there. The driver-private area is zeroed only when the tag set is allocated. Reproduced with a test target that leaves a residual iterator on a tag and then sends a C2HData for a WRITE_ZEROES command on the same tag: BUG: KASAN: wild-memory-access in _copy_to_iter+0x642/0x1330 Write of size 512 at addr ffe728c2175dfa81 by task kworker/0:1H/103 CPU: 0 UID: 0 PID: 103 Comm: kworker/0:1H Not tainted 7.2.0-rc5-NVMETCP-gf5098b6bae76 #1 PREEMPT(lazy) Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Workqueue: nvme_tcp_wq nvme_tcp_io_work Call Trace: <TASK> dump_stack_lvl+0x53/0x70 kasan_report+0xce/0x100 ? _copy_to_iter+0x642/0x1330 kasan_check_range+0x105/0x1b0 __asan_memcpy+0x3c/0x60 _copy_to_iter+0x642/0x1330 ? __pfx_sock_has_perm+0x10/0x10 ? worker_thread+0x45b/0xd10 ? pfxcopy_to_iter+0x10/0x10 ? _raw_spin_lock_bh+0x83/0xe0 ? pfxraw_spin_lock_bh+0x10/0x10 __skb_datagram_iter+0xf3/0x820 ? __pfx_simple_copy_to_iter+0x10/0x10 ? __asan_memcpy+0x3c/0x60 ? skb_copy_bits+0x58d/0x830 skb_copy_datagram_iter+0x37/0x120 nvme_tcp_recv_skb+0xa07/0x4320 ? __pfx_nvme_tcp_recv_skb+0x10/0x10 __tcp_read_sock+0x1ab/0x810 ? __pfx_nvme_tcp_recv_skb+0x10/0x10 ? __pfx_lock_sock_nested+0x10/0x10 ? pfx_tcp_read_sock+0x10/0x10 nvme_tcp_try_recv+0x152/0x1e0 ? __pfx_nvme_tcp_try_recv+0x10/0x10 ? __pfx_mutex_unlock+0x10/0x10 nvme_tcp_io_work+0x1e4/0x6c0 ? __schedule+0x181a/0x49f0 ? __pfx_nvme_tcp_io_work+0x10/0x10 process_one_work+0x633/0x1030 Keep the blk_rq_payload_bytes() test and add req->data_len to it. The old test is what rejects a C2HData naming a tag that is no longer in flight, because blk_update_request() zeroes rq->__data_len on completion; req->data_len and req->curr_bio are driver-private and survive completion, so they cannot stand in for it. Setup initialises the iterator only when both req->curr_bio and req->data_len are set, so the gate now tests the same two.

Timeline

1. Sep 11, 2026, 7:43 PM UTCCVE published
2. Oct 16, 2026, 7:22 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: yes · Technical impact: total

3. Oct 19, 2026, 8:47 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 25e5cb780e62bde432b401f312bb847edc78b432 · fixed in 32ea8ce96b9bd797c59c351ce490ffd97adaa8c0; From 25e5cb780e62bde432b401f312bb847edc78b432 · fixed in dd8906bb8f8d5bf1c9f861e1382c82b87bfe7cab; From 25e5cb780e62bde432b401f312bb847edc78b432 · fixed in 7ed0b61bbc145988be292c4d3ec580aebd8d2bcd; From 25e5cb780e62bde432b401f312bb847edc78b432 · fixed in b96e1ff75e5c0ad6e077ac002b1d30b0a2b49528; From 25e5cb780e62bde432b401f312bb847edc78b432 · fixed in b36161701cb366f416afdcf70771d432a7c74753; From 25e5cb780e62bde432b401f312bb847edc78b432 · fixed in 6a01b58263108eaf9869bb6f82f07709240c6589; From 25e5cb780e62bde432b401f312bb847edc78b432 · fixed in 641ad3a30ba560f0a9a610376c568d7b75d2a2aa; From 25e5cb780e62bde432b401f312bb847edc78b432 · fixed in 3a4aa9e6ad3e35f8e24d5eaf38ee4d437075fb36; From 5.4.36 · fixed in 5.5; From 5.6.8 · fixed in 5.7

• Linux Linux

  5.7

• KernelLinux

  From 5.7.0 · fixed in 5.10.270; From 5.11.0 · fixed in 5.15.221; From 5.16.0 · fixed in 6.1.188; From 6.2.0 · fixed in 6.6.157; From 6.7.0 · fixed in 6.12.109; From 6.13.0 · fixed in 6.18.50; From 6.19.0 · fixed in 7.2.4

References 8