From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 1BCE32561AE; Tue, 15 Jul 2025 13:47:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752587275; cv=none; b=HdHX9fNHoHbq7v9NKdVLW1uIgNPMgdEZOgUQ1vPPKoHSd7d0G2kr+GB9xFvnjCaRGZiFsYMrZdk0MXDNa0IozQ1Ds+s09oPUy8XcJkeYUVq7bZ/F5uEaAhkqOeGbl93UcdLryHbFAR2tWkxql2nMnaQkrXRmPdHdrEXuRg7Yb9Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1752587275; c=relaxed/simple; bh=ZfwB9NZgg5Jp+R0S5eJiJoKfpZShcmc9/0magCCfQ8o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=SlT9QsQkqRv+H7VJa3I2fAiQ7TbN/9hsz0Pw9DpSkhHRsGfS1EOy3OwdkxVRNksaUShdlPUXV1aCCtGJX96MvDVH3gk0RzLIffeFLnLUD6Kxlf9UneH5mjAXAr6hbNrJ3Z5seKBUMguWRLn9gGqb4nc5vWvipfQoJzjafRLVdDo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=QVhZx/I6; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="QVhZx/I6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A2513C4CEE3; Tue, 15 Jul 2025 13:47:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1752587275; bh=ZfwB9NZgg5Jp+R0S5eJiJoKfpZShcmc9/0magCCfQ8o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QVhZx/I6tNGSdPcvPvPvrM9SIWsk58hXksUFrqSIU7HCoGlwvqLOx9HTm/TAGdS/h eS2hSBDlT8VckhnO0zPs6a/H/EtfsIOzQYYhbhORUVM2lfPhroXCTWPw8XhYbmLt3y AjPJ4ZNwBsjRZI01ULFyiudOfSQDclep8rjHoh+w= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Stefano Garzarella , Michal Luczaj , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.1 09/88] vsock: Fix transport_{g2h,h2g} TOCTOU Date: Tue, 15 Jul 2025 15:13:45 +0200 Message-ID: <20250715130754.881089744@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250715130754.497128560@linuxfoundation.org> References: <20250715130754.497128560@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michal Luczaj [ Upstream commit 209fd720838aaf1420416494c5505096478156b4 ] vsock_find_cid() and vsock_dev_do_ioctl() may race with module unload. transport_{g2h,h2g} may become NULL after the NULL check. Introduce vsock_transport_local_cid() to protect from a potential null-ptr-deref. KASAN: null-ptr-deref in range [0x0000000000000118-0x000000000000011f] RIP: 0010:vsock_find_cid+0x47/0x90 Call Trace: __vsock_bind+0x4b2/0x720 vsock_bind+0x90/0xe0 __sys_bind+0x14d/0x1e0 __x64_sys_bind+0x6e/0xc0 do_syscall_64+0x92/0x1c0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 KASAN: null-ptr-deref in range [0x0000000000000118-0x000000000000011f] RIP: 0010:vsock_dev_do_ioctl.isra.0+0x58/0xf0 Call Trace: __x64_sys_ioctl+0x12d/0x190 do_syscall_64+0x92/0x1c0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Fixes: c0cfa2d8a788 ("vsock: add multi-transports support") Suggested-by: Stefano Garzarella Reviewed-by: Stefano Garzarella Signed-off-by: Michal Luczaj Link: https://patch.msgid.link/20250703-vsock-transports-toctou-v4-1-98f0eb530747@rbox.co Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/vmw_vsock/af_vsock.c | 27 +++++++++++++++++++++------ 1 file changed, 21 insertions(+), 6 deletions(-) diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c index a2271da346d34..42b5ff148d80b 100644 --- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -527,9 +527,25 @@ int vsock_assign_transport(struct vsock_sock *vsk, struct vsock_sock *psk) } EXPORT_SYMBOL_GPL(vsock_assign_transport); +/* + * Provide safe access to static transport_{h2g,g2h,dgram,local} callbacks. + * Otherwise we may race with module removal. Do not use on `vsk->transport`. + */ +static u32 vsock_registered_transport_cid(const struct vsock_transport **transport) +{ + u32 cid = VMADDR_CID_ANY; + + mutex_lock(&vsock_register_mutex); + if (*transport) + cid = (*transport)->get_local_cid(); + mutex_unlock(&vsock_register_mutex); + + return cid; +} + bool vsock_find_cid(unsigned int cid) { - if (transport_g2h && cid == transport_g2h->get_local_cid()) + if (cid == vsock_registered_transport_cid(&transport_g2h)) return true; if (transport_h2g && cid == VMADDR_CID_HOST) @@ -2320,18 +2336,17 @@ static long vsock_dev_do_ioctl(struct file *filp, unsigned int cmd, void __user *ptr) { u32 __user *p = ptr; - u32 cid = VMADDR_CID_ANY; int retval = 0; + u32 cid; switch (cmd) { case IOCTL_VM_SOCKETS_GET_LOCAL_CID: /* To be compatible with the VMCI behavior, we prioritize the * guest CID instead of well-know host CID (VMADDR_CID_HOST). */ - if (transport_g2h) - cid = transport_g2h->get_local_cid(); - else if (transport_h2g) - cid = transport_h2g->get_local_cid(); + cid = vsock_registered_transport_cid(&transport_g2h); + if (cid == VMADDR_CID_ANY) + cid = vsock_registered_transport_cid(&transport_h2g); if (put_user(cid, p) != 0) retval = -EFAULT; -- 2.39.5