{"id":2229581,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2229581/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-cifs-client/patch/20260428131756.922303-10-dhowells@redhat.com/","project":{"id":12,"url":"http://patchwork.ozlabs.org/api/1.1/projects/12/?format=json","name":"Linux CIFS Client","link_name":"linux-cifs-client","list_id":"linux-cifs.vger.kernel.org","list_email":"linux-cifs@vger.kernel.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260428131756.922303-10-dhowells@redhat.com>","date":"2026-04-28T13:17:39","name":"[v5,09/24] netfs: Fix overrun check in netfs_extract_user_iter()","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"8c155336f3086e410f0ddeea14ba23fd1c3976fe","submitter":{"id":59,"url":"http://patchwork.ozlabs.org/api/1.1/people/59/?format=json","name":"David Howells","email":"dhowells@redhat.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linux-cifs-client/patch/20260428131756.922303-10-dhowells@redhat.com/mbox/","series":[{"id":501852,"url":"http://patchwork.ozlabs.org/api/1.1/series/501852/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-cifs-client/list/?series=501852","date":"2026-04-28T13:17:35","name":"netfs: Miscellaneous fixes","version":5,"mbox":"http://patchwork.ozlabs.org/series/501852/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2229581/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2229581/checks/","tags":{},"headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-cifs@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=PoK3+Ude;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=172.234.253.10; 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c=relaxed/relaxed; d=redhat.com;\n\ts=mimecast20190719; t=1777382369;\n\th=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n\t to:to:cc:cc:mime-version:mime-version:\n\t content-transfer-encoding:content-transfer-encoding:\n\t in-reply-to:in-reply-to:references:references;\n\tbh=bHSQahnA7js1P4paGsZUSZ9WNRs6QCvVJJSxiV11wQI=;\n\tb=PoK3+Udej8Hpqibeltoe9U6qxEQ2eo/0TpB8AR01gIsB5+A7kVEcVMzXV65N7k8ZGCkmzI\n\tp29ScDih9LqR3MXEi6Zj5rRSZ/pV/4jjQrVqOO2VTzxKrPVBRXNcPgdiISiZkZZi47t5KK\n\tmA06ev1UFZuTwoc82fd7MwjOpQ6NmJI=","X-MC-Unique":"4t6aizAbP86H_MufK2aZGw-1","X-Mimecast-MFC-AGG-ID":"4t6aizAbP86H_MufK2aZGw_1777382362","From":"David Howells ","To":"Christian Brauner ","Cc":"David Howells ,\n\tPaulo Alcantara ,\n\tnetfs@lists.linux.dev,\n\tlinux-afs@lists.infradead.org,\n\tlinux-cifs@vger.kernel.org,\n\tceph-devel@vger.kernel.org,\n\tlinux-fsdevel@vger.kernel.org,\n\tlinux-kernel@vger.kernel.org","Subject":"[PATCH v5 09/24] netfs: Fix overrun check in\n 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-cifs@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"},"content":"Fix netfs_extract_user_iter() so that if iov_iter_extract_pages() overfills\npages[], then those pages don't get included in the iterator constructed at\nthe end of the function. If there was an overfill, memory corruption has\nalready happened.\n\nFixes: 85dd2c8ff368 (\"netfs: Add a function to extract a UBUF or IOVEC into a BVEC iterator\")\nCloses: https://sashiko.dev/#/patchset/20260427154639.180684-1-dhowells%40redhat.com\nSigned-off-by: David Howells \ncc: Paulo Alcantara \ncc: netfs@lists.linux.dev\ncc: linux-fsdevel@vger.kernel.org\n---\n fs/netfs/iterator.c | 21 ++++++++++++---------\n 1 file changed, 12 insertions(+), 9 deletions(-)","diff":"diff --git a/fs/netfs/iterator.c b/fs/netfs/iterator.c\nindex adca78747f23..932f745fa3b5 100644\n--- a/fs/netfs/iterator.c\n+++ b/fs/netfs/iterator.c\n@@ -72,21 +72,24 @@ ssize_t netfs_extract_user_iter(struct iov_iter *orig, size_t orig_len,\n \t\t\tbreak;\n \t\t}\n \n-\t\tif (ret > count) {\n-\t\t\tpr_err(\"get_pages rc=%zd more than %zu\\n\", ret, count);\n+\t\tif (WARN(ret > count,\n+\t\t\t \"%s: extract_pages overrun %zd > %zu bytes\\n\",\n+\t\t\t __func__, ret, count)) {\n+\t\t\tret = -EIO;\n \t\t\tbreak;\n \t\t}\n \n-\t\tcount -= ret;\n-\t\tret += offset;\n-\t\tcur_npages = DIV_ROUND_UP(ret, PAGE_SIZE);\n-\n-\t\tif (npages + cur_npages > max_pages) {\n-\t\t\tpr_err(\"Out of bvec array capacity (%u vs %u)\\n\",\n-\t\t\t npages + cur_npages, max_pages);\n+\t\tcur_npages = DIV_ROUND_UP(offset + ret, PAGE_SIZE);\n+\t\tif (WARN(cur_npages > max_pages - npages,\n+\t\t\t \"%s: extract_pages overrun %u > %u pages\\n\",\n+\t\t\t __func__, npages + cur_npages, max_pages)) {\n+\t\t\tret = -EIO;\n \t\t\tbreak;\n \t\t}\n \n+\t\tcount -= ret;\n+\t\tret += offset;\n+\n \t\tfor (i = 0; i < cur_npages; i++) {\n \t\t\tlen = ret > PAGE_SIZE ? PAGE_SIZE : ret;\n \t\t\tbvec_set_page(bv + npages + i, *pages++, len - offset, offset);\n","prefixes":["v5","09/24"]}