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 B01602EAB69; Tue, 22 Jul 2025 14:16:13 +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=1753193773; cv=none; b=QXb5+lfGw+uyGw4OFIbqvS39PUKB6/NDK0cz5iaX2cS6M971QyQaTB2O1Efm5Hsl3g8v6NJSGXOVsk2XBTZ/s2l3/+Um599aILnAX3qoWDvWkG2ODrdr21ylyPjxoizGc/Firo/52771m58SMpC1rAVmJDJnOpz/2bsVuFP3ilo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753193773; c=relaxed/simple; bh=6UqfK+HDjsjqgHsoquL2sjPA0DxMcK557ULo5Gof2nw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WAe/Ey8wgbIee0pi+Kb87VAIXaGUl/v5LOopF81EGSyw1N7GFVtq8sRIhtLJ8eWectuE6hL1mAmVUUm+hBqvrITI6lMAT8HNM23Q7nW16a6PF+AqDGcUt6d+umH9HGjearQXN+N7sDQ/ziyQ49p0cEt+3AXREutq9FbKj+taVjM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=DEIoFje1; 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="DEIoFje1" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CFD6FC4CEEB; Tue, 22 Jul 2025 14:16:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1753193773; bh=6UqfK+HDjsjqgHsoquL2sjPA0DxMcK557ULo5Gof2nw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DEIoFje1zQGwT63+8l/1EWZbT7nFGqhPJ+il9IlJyeVUmM9bQlvxVdBlr5rTJwx/A oj2kDGxBNkvYHfqiHIL6iC/ua+2LS85SI0/ywb1BA9JQcqc3N+7t+42W4uilLKVVfx ue9rdJ42G4zppMzTKj4S8ip5rQ8aLHLUhzFRXAGo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Stefan Metzmacher , David Howells , Paulo Alcantara , linux-cifs@vger.kernel.org, netfs@lists.linux.dev, linux-fsdevel@vger.kernel.org, Steve French Subject: [PATCH 6.15 181/187] cifs: Fix the smbd_response slab to allow usercopy Date: Tue, 22 Jul 2025 15:45:51 +0200 Message-ID: <20250722134352.509236048@linuxfoundation.org> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20250722134345.761035548@linuxfoundation.org> References: <20250722134345.761035548@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Howells commit 43e7e284fc77b710d899569360ea46fa3374ae22 upstream. The handling of received data in the smbdirect client code involves using copy_to_iter() to copy data from the smbd_reponse struct's packet trailer to a folioq buffer provided by netfslib that encapsulates a chunk of pagecache. If, however, CONFIG_HARDENED_USERCOPY=y, this will result in the checks then performed in copy_to_iter() oopsing with something like the following: CIFS: Attempting to mount //172.31.9.1/test CIFS: VFS: RDMA transport established usercopy: Kernel memory exposure attempt detected from SLUB object 'smbd_response_0000000091e24ea1' (offset 81, size 63)! ------------[ cut here ]------------ kernel BUG at mm/usercopy.c:102! ... RIP: 0010:usercopy_abort+0x6c/0x80 ... Call Trace: __check_heap_object+0xe3/0x120 __check_object_size+0x4dc/0x6d0 smbd_recv+0x77f/0xfe0 [cifs] cifs_readv_from_socket+0x276/0x8f0 [cifs] cifs_read_from_socket+0xcd/0x120 [cifs] cifs_demultiplex_thread+0x7e9/0x2d50 [cifs] kthread+0x396/0x830 ret_from_fork+0x2b8/0x3b0 ret_from_fork_asm+0x1a/0x30 The problem is that the smbd_response slab's packet field isn't marked as being permitted for usercopy. Fix this by passing parameters to kmem_slab_create() to indicate that copy_to_iter() is permitted from the packet region of the smbd_response slab objects, less the header space. Fixes: ee4cdf7ba857 ("netfs: Speed up buffered reading") Reported-by: Stefan Metzmacher Link: https://lore.kernel.org/r/acb7f612-df26-4e2a-a35d-7cd040f513e1@samba.org/ Signed-off-by: David Howells Reviewed-by: Stefan Metzmacher Tested-by: Stefan Metzmacher cc: Paulo Alcantara cc: linux-cifs@vger.kernel.org cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/smb/client/smbdirect.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) --- a/fs/smb/client/smbdirect.c +++ b/fs/smb/client/smbdirect.c @@ -1452,6 +1452,9 @@ static int allocate_caches_and_workqueue char name[MAX_NAME_LEN]; int rc; + if (WARN_ON_ONCE(sp->max_recv_size < sizeof(struct smbdirect_data_transfer))) + return -ENOMEM; + scnprintf(name, MAX_NAME_LEN, "smbd_request_%p", info); info->request_cache = kmem_cache_create( @@ -1469,12 +1472,17 @@ static int allocate_caches_and_workqueue goto out1; scnprintf(name, MAX_NAME_LEN, "smbd_response_%p", info); + + struct kmem_cache_args response_args = { + .align = __alignof__(struct smbd_response), + .useroffset = (offsetof(struct smbd_response, packet) + + sizeof(struct smbdirect_data_transfer)), + .usersize = sp->max_recv_size - sizeof(struct smbdirect_data_transfer), + }; info->response_cache = - kmem_cache_create( - name, - sizeof(struct smbd_response) + - sp->max_recv_size, - 0, SLAB_HWCACHE_ALIGN, NULL); + kmem_cache_create(name, + sizeof(struct smbd_response) + sp->max_recv_size, + &response_args, SLAB_HWCACHE_ALIGN); if (!info->response_cache) goto out2;