From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 CD060477E32 for ; Tue, 28 Apr 2026 13:19:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777382370; cv=none; b=o8ugrUpdHFQ8KKuBxieObITkjv5dcNVt6ta487XSP0L6MKI70X6cKJ4FZ+tH+lEqx14FSr8XUQLzIoi3YTMvKOms6yVMkxvjYglzDisRXnAv7FWIvAjwF9jwKu/wDz7HOtVggx7vW/rmxo+JZf4me8YBKaJLz9aqgOwe8tzQvWY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777382370; c=relaxed/simple; bh=6aS16OhU7wJB8E9ZvNzMBoTTc64B5xcaExT2qrf2F8c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=MWVozDfK1ap6LYZ7/5puP2hzHFZkX7xSV8FyhgGO7wucFkICtA04SRFJGCy6kf/e4YKcGyjZnBeBxaq+ThLu+EIHPDxafWB267/84dF1y1Ms9hxTXB62PntG3Yd0pBr8+wa9/HtZbIO53IpUgyEpftHyBGvKn4rNIIluOy+OzAA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=K95QODXs; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="K95QODXs" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1777382367; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=bHSQahnA7js1P4paGsZUSZ9WNRs6QCvVJJSxiV11wQI=; b=K95QODXsW5HxGyT+mCNxzzodFOpE/3WaZO/Xa15/Cts4Dv9V+qDROhrql9UuzFEM1pYOtK mGfa/265adeyP5xRl2G3oQMvKFkBD2BitCeFSCkPU8A0yFpZRM9MO8MpMp4zC5ijTgBsZR gHDMc3rQa7VqoVbZUxI5nt4y0QHs8HE= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-512-4t6aizAbP86H_MufK2aZGw-1; Tue, 28 Apr 2026 09:19:24 -0400 X-MC-Unique: 4t6aizAbP86H_MufK2aZGw-1 X-Mimecast-MFC-AGG-ID: 4t6aizAbP86H_MufK2aZGw_1777382362 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0BC10186057E; Tue, 28 Apr 2026 13:18:47 +0000 (UTC) Received: from warthog.procyon.org.com (unknown [10.44.32.126]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 5653019560AB; Tue, 28 Apr 2026 13:18:44 +0000 (UTC) From: David Howells To: Christian Brauner Cc: David Howells , Paulo Alcantara , netfs@lists.linux.dev, linux-afs@lists.infradead.org, linux-cifs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v5 09/24] netfs: Fix overrun check in netfs_extract_user_iter() Date: Tue, 28 Apr 2026 14:17:39 +0100 Message-ID: <20260428131756.922303-10-dhowells@redhat.com> In-Reply-To: <20260428131756.922303-1-dhowells@redhat.com> References: <20260428131756.922303-1-dhowells@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Fix netfs_extract_user_iter() so that if iov_iter_extract_pages() overfills pages[], then those pages don't get included in the iterator constructed at the end of the function. If there was an overfill, memory corruption has already happened. Fixes: 85dd2c8ff368 ("netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator") Closes: https://sashiko.dev/#/patchset/20260427154639.180684-1-dhowells%40redhat.com Signed-off-by: David Howells cc: Paulo Alcantara cc: netfs@lists.linux.dev cc: linux-fsdevel@vger.kernel.org --- fs/netfs/iterator.c | 21 ++++++++++++--------- 1 file changed, 12 insertions(+), 9 deletions(-) diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c index adca78747f23..932f745fa3b5 100644 --- a/fs/netfs/iterator.c +++ b/fs/netfs/iterator.c @@ -72,21 +72,24 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len, break; } - if (ret > count) { - pr_err("get_pages rc=%zd more than %zu\n", ret, count); + if (WARN(ret > count, + "%s: extract_pages overrun %zd > %zu bytes\n", + __func__, ret, count)) { + ret = -EIO; break; } - count -= ret; - ret += offset; - cur_npages = DIV_ROUND_UP(ret, PAGE_SIZE); - - if (npages + cur_npages > max_pages) { - pr_err("Out of bvec array capacity (%u vs %u)\n", - npages + cur_npages, max_pages); + cur_npages = DIV_ROUND_UP(offset + ret, PAGE_SIZE); + if (WARN(cur_npages > max_pages - npages, + "%s: extract_pages overrun %u > %u pages\n", + __func__, npages + cur_npages, max_pages)) { + ret = -EIO; break; } + count -= ret; + ret += offset; + for (i = 0; i < cur_npages; i++) { len = ret > PAGE_SIZE ? PAGE_SIZE : ret; bvec_set_page(bv + npages + i, *pages++, len - offset, offset);