{"id":2225004,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2225004/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-cifs-client/patch/20260420083705.1009074-4-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":"<20260420083705.1009074-4-dhowells@redhat.com>","date":"2026-04-20T08:36:54","name":"[03/11] netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"dfd8940acda50335a85fa2366de1b26c097d3a25","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/20260420083705.1009074-4-dhowells@redhat.com/mbox/","series":[{"id":500568,"url":"http://patchwork.ozlabs.org/api/1.1/series/500568/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-cifs-client/list/?series=500568","date":"2026-04-20T08:36:52","name":"netfs: Further miscellaneous fixes","version":1,"mbox":"http://patchwork.ozlabs.org/series/500568/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2225004/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2225004/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=W4BHB2RD;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c04:e001:36c::12fc:5321; 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c=relaxed/relaxed; d=redhat.com;\n\ts=mimecast20190719; t=1776674256;\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=RxAt8h3Z5s//UgNA1V43SWKyEAFpFt5qMrF31FeEFDE=;\n\tb=W4BHB2RD2e6FO2caVljvNFPhVBTvG7oBavwqe+Yg+oL1065mrIS4sePF2Y1cqFect5Eyte\n\te+UFroh8OydVABvrse0x011VrYUpQQLxqnu9JQG+k206dalugviv2fvFhisQjW3NgfWWm9\n\tnUtBD0DBHlf5rHTpKFqr1LLYiBNtwBg=","X-MC-Unique":"x4HYGNN4MX-KuWrsWdkrPA-1","X-Mimecast-MFC-AGG-ID":"x4HYGNN4MX-KuWrsWdkrPA_1776674251","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,\n\tViacheslav Dubeyko ,\n\tMatthew Wilcox ","Subject":"[PATCH 03/11] netfs: Fix potential UAF in\n netfs_unlock_abandoned_read_pages()","Date":"Mon, 20 Apr 2026 09:36:54 +0100","Message-ID":"<20260420083705.1009074-4-dhowells@redhat.com>","In-Reply-To":"<20260420083705.1009074-1-dhowells@redhat.com>","References":"<20260420083705.1009074-1-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 3.4.1 on 10.30.177.4"},"content":"netfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it\nis wanting to unlock and compares that to rreq->no_unlock_folio so that it\ndoesn't unlock a folio being read for netfs_perform_write() or\nnetfs_write_begin().\n\nHowever, given that netfs_unlock_abandoned_read_pages() is called _after_\nNETFS_RREQ_IN_PROGRESS is cleared, the one folio that it's not allowed to\ndereference is the one specified by ->no_unlock_folio as ownership\nimmediately reverts to the caller.\n\nFix this by storing the folio pointer instead and using that rather than\nthe index. Also fix netfs_unlock_read_folio() where the same applies.\n\nFixes: ee4cdf7ba857 (\"netfs: Speed up buffered reading\")\nCloses: https://sashiko.dev/#/patchset/20260414082004.3756080-1-dhowells%40redhat.com\nSigned-off-by: David Howells \ncc: Paulo Alcantara \ncc: Viacheslav Dubeyko \ncc: Matthew Wilcox \ncc: netfs@lists.linux.dev\ncc: linux-fsdevel@vger.kernel.org\n---\n fs/netfs/buffered_read.c | 4 ++--\n fs/netfs/read_collect.c | 2 +-\n fs/netfs/read_retry.c | 2 +-\n include/linux/netfs.h | 2 +-\n 4 files changed, 5 insertions(+), 5 deletions(-)","diff":"diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c\nindex 51caad535438..b4d271538f75 100644\n--- a/fs/netfs/buffered_read.c\n+++ b/fs/netfs/buffered_read.c\n@@ -670,7 +670,7 @@ int netfs_write_begin(struct netfs_inode *ctx,\n \t\tret = PTR_ERR(rreq);\n \t\tgoto error;\n \t}\n-\trreq->no_unlock_folio\t= folio->index;\n+\trreq->no_unlock_folio\t= folio;\n \t__set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags);\n \n \tret = netfs_begin_cache_read(rreq, ctx);\n@@ -736,7 +736,7 @@ int netfs_prefetch_for_write(struct file *file, struct folio *folio,\n \t\tgoto error;\n \t}\n \n-\trreq->no_unlock_folio = folio->index;\n+\trreq->no_unlock_folio = folio;\n \t__set_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags);\n \tret = netfs_begin_cache_read(rreq, ctx);\n \tif (ret == -ENOMEM || ret == -EINTR || ret == -ERESTARTSYS)\ndiff --git a/fs/netfs/read_collect.c b/fs/netfs/read_collect.c\nindex e5f6665b3341..eae067e3eaa5 100644\n--- a/fs/netfs/read_collect.c\n+++ b/fs/netfs/read_collect.c\n@@ -83,7 +83,7 @@ static void netfs_unlock_read_folio(struct netfs_io_request *rreq,\n \t}\n \n just_unlock:\n-\tif (folio->index == rreq->no_unlock_folio &&\n+\tif (folio == rreq->no_unlock_folio &&\n \t test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags)) {\n \t\t_debug(\"no unlock\");\n \t} else {\ndiff --git a/fs/netfs/read_retry.c b/fs/netfs/read_retry.c\nindex 68fc869513ef..999177426141 100644\n--- a/fs/netfs/read_retry.c\n+++ b/fs/netfs/read_retry.c\n@@ -288,7 +288,7 @@ void netfs_unlock_abandoned_read_pages(struct netfs_io_request *rreq)\n \t\t\tstruct folio *folio = folioq_folio(p, slot);\n \n \t\t\tif (folio && !folioq_is_marked2(p, slot)) {\n-\t\t\t\tif (folio->index == rreq->no_unlock_folio &&\n+\t\t\t\tif (folio == rreq->no_unlock_folio &&\n \t\t\t\t test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO,\n \t\t\t\t\t &rreq->flags)) {\n \t\t\t\t\t_debug(\"no unlock\");\ndiff --git a/include/linux/netfs.h b/include/linux/netfs.h\nindex ba17ac5bf356..62a528f90666 100644\n--- a/include/linux/netfs.h\n+++ b/include/linux/netfs.h\n@@ -252,7 +252,7 @@ struct netfs_io_request {\n \tunsigned long long\tcollected_to;\t/* Point we've collected to */\n \tunsigned long long\tcleaned_to;\t/* Position we've cleaned folios to */\n \tunsigned long long\tabandon_to;\t/* Position to abandon folios to */\n-\tpgoff_t\t\t\tno_unlock_folio; /* Don't unlock this folio after read */\n+\tconst struct folio\t*no_unlock_folio; /* Don't unlock this folio after read */\n \tunsigned int\t\tdirect_bv_count; /* Number of elements in direct_bv[] */\n \tunsigned int\t\tdebug_id;\n \tunsigned int\t\trsize;\t\t/* Maximum read size (0 for none) */\n","prefixes":["03/11"]}