kernel/linux.git/fs/smb/server/server.c, branch v6.1.168

ksmbd: fix infinite loop caused by next_smb2_rcv_hdr_off reset in error paths

2026-02-19T15:25:14+00:00

commit 010eb01ce23b34b50531448b0da391c7f05a72af upstream. The problem occurs when a signed request fails smb2 signature verification check. In __process_request(), if check_sign_req() returns an error, set_smb2_rsp_status(work, STATUS_ACCESS_DENIED) is called. set_smb2_rsp_status() set work->next_smb2_rcv_hdr_off as zero. By resetting next_smb2_rcv_hdr_off to zero, the pointer to the next command in the chain is lost. Consequently, is_chained_smb2_message() continues to point to the same request header instead of advancing. If the header's NextCommand field is non-zero, the function returns true, causing __handle_ksmbd_work() to repeatedly process the same failed request in an infinite loop. This results in the kernel log being flooded with "bad smb2 signature" messages and high CPU usage. This patch fixes the issue by changing the return value from SERVER_HANDLER_CONTINUE to SERVER_HANDLER_ABORT. This ensures that the processing loop terminates immediately rather than attempting to continue from an invalidated offset. Reported-by: tianshuo han Cc: stable@vger.kernel.org Signed-off-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

ksmbd: fix racy issue from session lookup and expire

2024-12-19T17:08:48+00:00

commit b95629435b84b9ecc0c765995204a4d8a913ed52 upstream. Increment the session reference count within the lock for lookup to avoid racy issue with session expire. Cc: stable@vger.kernel.org Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-25737 Signed-off-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

ksmbd: fix slab-use-after-free in smb3_preauth_hash_rsp

2024-11-14T12:15:14+00:00

commit b8fc56fbca7482c1e5c0e3351c6ae78982e25ada upstream. ksmbd_user_session_put should be called under smb3_preauth_hash_rsp(). It will avoid freeing session before calling smb3_preauth_hash_rsp(). Cc: stable@vger.kernel.org # v5.15+ Reported-by: Norbert Szetei Tested-by: Norbert Szetei Signed-off-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

ksmbd: fix user-after-free from session log off

2024-10-22T13:56:39+00:00

commit 7aa8804c0b67b3cb263a472d17f2cb50d7f1a930 upstream. There is racy issue between smb2 session log off and smb2 session setup. It will cause user-after-free from session log off. This add session_lock when setting SMB2_SESSION_EXPIRED and referece count to session struct not to free session while it is being used. Cc: stable@vger.kernel.org # v5.15+ Reported-by: zdi-disclosures@trendmicro.com # ZDI-CAN-25282 Signed-off-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

ksmbd: fix slab-out-of-bounds in smb2_allocate_rsp_buf

2024-04-27T15:07:17+00:00

commit c119f4ede3fa90a9463f50831761c28f989bfb20 upstream. If ->ProtocolId is SMB2_TRANSFORM_PROTO_NUM, smb2 request size validation could be skipped. if request size is smaller than sizeof(struct smb2_query_info_req), slab-out-of-bounds read can happen in smb2_allocate_rsp_buf(). This patch allocate response buffer after decrypting transform request. smb3_decrypt_req() will validate transform request size and avoid slab-out-of-bound in smb2_allocate_rsp_buf(). Reported-by: Norbert Szetei Cc: stable@vger.kernel.org Signed-off-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman

ksmbd: fix race condition between tree conn lookup and disconnect

2024-01-05T14:18:33+00:00

[ Upstream commit 33b235a6e6ebe0f05f3586a71e8d281d00f71e2e ] if thread A in smb2_write is using work-tcon, other thread B use smb2_tree_disconnect free the tcon, then thread A will use free'd tcon. Time + Thread A | Thread A smb2_write | smb2_tree_disconnect | | | kfree(tree_conn) | // UAF! | work->tcon->share_conf | + This patch add state, reference count and lock for tree conn to fix race condition issue. Reported-by: luosili Signed-off-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin

ksmbd: return invalid parameter error response if smb2 request is invalid

2024-01-05T14:18:32+00:00

[ Upstream commit f2f11fca5d7112e2f91c4854cddd68a059fdaa4a ] If smb2 request from client is invalid, The following kernel oops could happen. The patch e2b76ab8b5c9: "ksmbd: add support for read compound" leads this issue. When request is invalid, It doesn't set anything in the response buffer. This patch add missing set invalid parameter error response. [ 673.085542] ksmbd: cli req too short, len 184 not 142. cmd:5 mid:109 [ 673.085580] BUG: kernel NULL pointer dereference, address: 0000000000000000 [ 673.085591] #PF: supervisor read access in kernel mode [ 673.085600] #PF: error_code(0x0000) - not-present page [ 673.085608] PGD 0 P4D 0 [ 673.085620] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 673.085631] CPU: 3 PID: 1039 Comm: kworker/3:0 Not tainted 6.6.0-rc2-tmt #16 [ 673.085643] Hardware name: AZW U59/U59, BIOS JTKT001 05/05/2022 [ 673.085651] Workqueue: ksmbd-io handle_ksmbd_work [ksmbd] [ 673.085719] RIP: 0010:ksmbd_conn_write+0x68/0xc0 [ksmbd] [ 673.085808] RAX: 0000000000000000 RBX: ffff88811ade4f00 RCX: 0000000000000000 [ 673.085817] RDX: 0000000000000000 RSI: ffff88810c2a9780 RDI: ffff88810c2a9ac0 [ 673.085826] RBP: ffffc900005e3e00 R08: 0000000000000000 R09: 0000000000000000 [ 673.085834] R10: ffffffffa3168160 R11: 63203a64626d736b R12: ffff8881057c8800 [ 673.085842] R13: ffff8881057c8820 R14: ffff8882781b2380 R15: ffff8881057c8800 [ 673.085852] FS: 0000000000000000(0000) GS:ffff888278180000(0000) knlGS:0000000000000000 [ 673.085864] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 673.085872] CR2: 0000000000000000 CR3: 000000015b63c000 CR4: 0000000000350ee0 [ 673.085883] Call Trace: [ 673.085890] [ 673.085900] ? show_regs+0x6a/0x80 [ 673.085916] ? __die+0x25/0x70 [ 673.085926] ? page_fault_oops+0x154/0x4b0 [ 673.085938] ? tick_nohz_tick_stopped+0x18/0x50 [ 673.085954] ? __irq_work_queue_local+0xba/0x140 [ 673.085967] ? do_user_addr_fault+0x30f/0x6c0 [ 673.085979] ? exc_page_fault+0x79/0x180 [ 673.085992] ? asm_exc_page_fault+0x27/0x30 [ 673.086009] ? ksmbd_conn_write+0x68/0xc0 [ksmbd] [ 673.086067] ? ksmbd_conn_write+0x46/0xc0 [ksmbd] [ 673.086123] handle_ksmbd_work+0x28d/0x4b0 [ksmbd] [ 673.086177] process_one_work+0x178/0x350 [ 673.086193] ? __pfx_worker_thread+0x10/0x10 [ 673.086202] worker_thread+0x2f3/0x420 [ 673.086210] ? _raw_spin_unlock_irqrestore+0x27/0x50 [ 673.086222] ? __pfx_worker_thread+0x10/0x10 [ 673.086230] kthread+0x103/0x140 [ 673.086242] ? __pfx_kthread+0x10/0x10 [ 673.086253] ret_from_fork+0x39/0x60 [ 673.086263] ? __pfx_kthread+0x10/0x10 [ 673.086274] ret_from_fork_asm+0x1b/0x30 Fixes: e2b76ab8b5c9 ("ksmbd: add support for read compound") Reported-by: Tom Talpey Signed-off-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin

ksmbd: remove experimental warning

2024-01-05T14:18:32+00:00

[ Upstream commit f5069159f32c8c943e047f22731317463c8e9b84 ] ksmbd has made significant improvements over the past two years and is regularly tested and used. Remove the experimental warning. Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin

ksmbd: add support for read compound

2024-01-05T14:18:31+00:00

[ Upstream commit e2b76ab8b5c9327ab2dae6da05d0752eb2f4771d ] MacOS sends a compound request including read to the server (e.g. open-read-close). So far, ksmbd has not handled read as a compound request. For compatibility between ksmbd and an OS that supports SMB, This patch provides compound support for read requests. Signed-off-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin

ksmbd: Convert to use sysfs_emit()/sysfs_emit_at() APIs

2024-01-05T14:18:27+00:00

[ Upstream commit 72ee45fd46d0d3578c4e6046f66fae3218543ce3 ] Follow the advice of the Documentation/filesystems/sysfs.rst and show() should only use sysfs_emit() or sysfs_emit_at() when formatting the value to be returned to user space. Signed-off-by: ye xingchen Reviewed-by: Sergey Senozhatsky Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin