From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D0CA655820F for ; Fri, 11 Sep 2026 19:50:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156241; cv=none; b=V7O+iz7y6SmBCoGeOGIyOsMD/3JwtoveJEGMSoccaXFwZ5bLA6TOTSv+BRptgQAGlcVPC2MG2XWnW7FV/DOl2Zr7jea7COFgVCrqCD2K/rX+6EvlFcajv8d3ClFr+hkSMvRjfnZXEvYkQnCRML0/6GIyJpHa01lU+MaAusme+IY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789156241; c=relaxed/simple; bh=MX5E1LgytA2wxLLDC/k+hf3TMcjg9RDHar4/jZPP6nw=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=DQ64cB1ea2Lk/jx50BPY2rcFvYXlsSHl4SsCAmG2f0FVgWD+SvOv/DKNZqYHYYuMGvwydn1tJJn6x3u01vJqQGqKrEc62AlLKYvmud/cXTI5/ijyK4winOTXZKKBqmEzcqWm3la3mOq+I2nmp0MDFIPPTVO6q6QkzkWTgId/xLw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=IZEQpaRC; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="IZEQpaRC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 00C251F0089A; Fri, 11 Sep 2026 19:50:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789156227; bh=bRQ8eU2folfs6JNOIybpokVJs4LU+AODhwbW3aL0MW8=; h=From:To:Cc:Subject:Date:Reply-To; b=IZEQpaRClGHOFGpMOvv3xQqvvFaSYZGIkwovhKfSTIC2RcTvxvoi65GCbv2kPqRjF Ly1I8+8o3Ziaxo2blV/kB5HLewY5qAiPPuaqH+XBfj4E69GM997VSzLt8/+po3yNqN v8gmtV/16qMH4UQPXaAgY7eh36Idj3+g6NAKnfBE= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-80986: net/smc: bound the peer rkey counts in SMC-Rv2 LLC messages Date: Fri, 11 Sep 2026 21:41:32 +0200 Message-ID: <2026091147-CVE-2026-80986-5335@gregkh> X-Mailer: git-send-email 2.55.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=7945; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=0DwGYXjqJszDmZZdm84IbgtJkqhAnue/ijB3CfNa3rY=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlLIu0nhqsLdR2uPtDY0jebrex66sbelI597eu4Nq790 qJ1V+tdRywLgyATg6yYIsuXbTxH91ccUvQytD0NM4eVCWQIAxenAExk7yeGBWvyJy7TXxXj5Vsw IfNqb8NWvbjjmkBR7YarufFuRzbyrZB7sYxtjfHPdywA X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: net/smc: bound the peer rkey counts in SMC-Rv2 LLC messages On a link whose device has max_recv_sge == 1 there is no shared v2 receive buffer, and smc_llc_save_add_link_rkeys() takes the v2 extension from 44 bytes past the start of the queue entry's inline message: ext = (struct smc_llc_msg_add_link_v2_ext *)(llc_msg + SMC_WR_TX_SIZE); The entry is a 72-byte allocation and the extension starts at offset 68, so ext->num_rkeys at offset 94 is already past it. This happens on every SMC-Rv2 link addition, whatever the peer sends: [ 2.490065] BUG: KASAN: slab-out-of-bounds in smc_llc_save_add_link_rkeys+0x333/0x350 [ 2.490431] Read of size 2 at addr ffff8880056406de by task smctest/106 [ 2.490709] [ 2.490792] CPU: 0 UID: 0 PID: 106 Comm: smctest Not tainted 7.2.0-rc5-p1-g77a5d9d9c99f #32 PREEMPT(lazy) [ 2.490795] 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 [ 2.490798] Call Trace: [ 2.490803] [ 2.490805] dump_stack_lvl+0x53/0x70 [ 2.490810] print_report+0xd0/0x630 [ 2.490828] ? __pfx__raw_spin_lock_irqsave+0x10/0x10 [ 2.490832] ? smc_llc_save_add_link_rkeys+0x333/0x350 [ 2.490834] kasan_report+0xce/0x100 [ 2.490836] ? smc_llc_save_add_link_rkeys+0x333/0x350 [ 2.490837] smc_llc_save_add_link_rkeys+0x333/0x350 [ 2.490839] ? smcr_buf_map_lgr+0x1bf/0x2b0 [ 2.490844] smc_llc_cli_add_link+0xca7/0x1e80 [ 2.490848] ? smc_llc_wait+0x355/0x810 [ 2.490850] ? __pfx_smc_llc_wait+0x10/0x10 [ 2.490851] ? __pfx_smc_llc_cli_add_link+0x10/0x10 [ 2.490853] ? __pfx_autoremove_wake_function+0x10/0x10 [ 2.490863] __smc_connect+0x3f5c/0x4980 [ 2.490873] ? __pfx_kernel_connect+0x10/0x10 [ 2.490888] ? __pfx___smc_connect+0x10/0x10 [ 2.490891] ? release_sock+0x148/0x1d0 [ 2.490894] smc_connect+0x42c/0x580 [ 2.490896] __sys_connect+0xfc/0x130 [ 2.490898] ? __pfx___sys_connect+0x10/0x10 [ 2.490900] ? handle_mm_fault+0x1a1/0x430 [ 2.490908] __x64_sys_connect+0x6d/0xb0 [ 2.490909] ? fpregs_assert_state_consistent+0x56/0xe0 [ 2.490917] do_syscall_64+0xf9/0x540 [ 2.490921] entry_SYSCALL_64_after_hwframe+0x77/0x7f [ 2.490924] RIP: 0033:0x421bb4 [ 2.490927] Code: ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 80 3d ad 34 09 00 00 74 13 b8 2a 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 4c c3 0f 1f 00 55 48 89 e5 48 83 ec 10 89 55 [ 2.490929] RSP: 002b:00007ffd473b01a8 EFLAGS: 00000202 ORIG_RAX: 000000000000002a [ 2.490935] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000421bb4 [ 2.490936] RDX: 0000000000000010 RSI: 00007ffd473b01d0 RDI: 0000000000000003 [ 2.490937] RBP: 0000000000003930 R08: 0000000000000004 R09: 0000000000000000 [ 2.490938] R10: 00007ffd473b0f98 R11: 0000000000000202 R12: 0000000000000006 [ 2.490939] R13: 00007ffd473b0f87 R14: 0000000000000003 R15: 00007ffd473b0f90 [ 2.490940] [ 2.490941] [ 2.499545] Allocated by task 44: [ 2.499693] kasan_save_stack+0x33/0x60 [ 2.499860] kasan_save_track+0x14/0x30 [ 2.500026] __kasan_kmalloc+0x8f/0xa0 [ 2.500190] __kmalloc_cache_noprof+0x158/0x370 [ 2.500393] smc_llc_enqueue+0x72/0x560 [ 2.500559] smc_wr_rx_tasklet_fn+0x474/0xa80 [ 2.500747] tasklet_action_common+0x20f/0x8a0 [ 2.500945] handle_softirqs+0x18e/0x590 [ 2.501115] do_softirq+0x3b/0x60 [ 2.501266] __local_bh_enable_ip+0x61/0x70 [ 2.501446] __alloc_skb+0x732/0x890 [ 2.501604] rxe_init_packet+0x16b/0x4f0 [ 2.501783] prepare_ack_packet+0xb8/0x830 [ 2.501962] rxe_receiver+0x495/0x96e0 [ 2.502125] do_work+0x144/0x470 [ 2.502269] process_one_work+0x633/0x1030 [ 2.502450] worker_thread+0x45b/0xd10 [ 2.502617] kthread+0x2c6/0x3b0 [ 2.502762] ret_from_fork+0x36e/0x5a0 [ 2.502925] ret_from_fork_asm+0x1a/0x30 [ 2.503103] [ 2.503177] The buggy address belongs to the object at ffff888005640680 [ 2.503177] which belongs to the cache kmalloc-96 of size 96 [ 2.503692] The buggy address is located 22 bytes to the right of [ 2.503692] allocated 72-byte region [ffff888005640680, ffff8880056406c8) [ 2.504227] [ 2.504300] The buggy address belongs to the physical page: [ 2.504535] page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5640 [ 2.504865] flags: 0x100000000000000(node=0|zone=1) [ 2.505076] page_type: f5(slab) [ 2.505221] raw: 0100000000000000 ffff888001041280 dead000000000122 0000000000000000 [ 2.505544] raw: 0000000000000000 0000000000200020 00000000f5000000 0000000000000000 [ 2.505867] page dumped because: kasan: bad access detected [ 2.506102] [ 2.506176] Memory state around the buggy address: [ 2.506380] ffff888005640580: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc [ 2.506683] ffff888005640600: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc [ 2.506987] >ffff888005640680: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc [ 2.507291] ^ [ 2.507548] ffff888005640700: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc [ 2.507850] ffff888005640780: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc Whatever that read finds then bounds the ext->rt[] loop, so a peer that declares 255 rkeys reads much further. smc_llc_rmt_delete_rkey() has the same shape for llcv2->rkey[]. Bound both loops by the buffer they read from, and skip the extension altogether when there is no shared v2 receive buffer. The extension does arrive on the link, but smc_llc_enqueue() copies only sizeof(union smc_llc_msg) into the queue entry, so what that code read past the 44 inline bytes was heap and not peer data. The Linux kernel CVE team has assigned CVE-2026-80986 to this issue. Affected and fixed versions =========================== Issue introduced in 6.14 with commit 27ef6a9981fe74191849966a6d5e0400a4008ab8 and fixed in 6.18.50 with commit 486c699a8cde82c1d9b4f443eeab4ddf86358cb0 Issue introduced in 6.14 with commit 27ef6a9981fe74191849966a6d5e0400a4008ab8 and fixed in 7.2.4 with commit 5e5d9e6df677d30a2203d257b5fd8b99814fa607 Issue introduced in 6.14 with commit 27ef6a9981fe74191849966a6d5e0400a4008ab8 and fixed in 7.3-rc1 with commit 2d1e7c5aaa3326e95e2058457f172ca99a9a4577 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-80986 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: net/smc/smc_llc.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/486c699a8cde82c1d9b4f443eeab4ddf86358cb0 https://git.kernel.org/stable/c/5e5d9e6df677d30a2203d257b5fd8b99814fa607 https://git.kernel.org/stable/c/2d1e7c5aaa3326e95e2058457f172ca99a9a4577