linux-kernel - [PATCH] buildid: validate page-backed file before parsing build ID

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20251223103214.2412446-1-wangjinchao600@gmail.com>
Date: Tue, 23 Dec 2025 18:32:07 +0800
From: Jinchao Wang <wangjinchao600@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>,
	Song Liu <song@...nel.org>,
	Jiri Olsa <jolsa@...nel.org>,
	Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Andrii Nakryiko <andrii@...nel.org>,
	Martin KaFai Lau <martin.lau@...ux.dev>,
	Eduard Zingerman <eddyz87@...il.com>,
	Yonghong Song <yonghong.song@...ux.dev>,
	John Fastabend <john.fastabend@...il.com>,
	KP Singh <kpsingh@...nel.org>,
	Stanislav Fomichev <sdf@...ichev.me>,
	Hao Luo <haoluo@...gle.com>,
	linux-kernel@...r.kernel.org,
	bpf@...r.kernel.org
Cc: Jinchao Wang <wangjinchao600@...il.com>,
	syzbot+e008db2ac01e282550ee@...kaller.appspotmail.com
Subject: [PATCH] buildid: validate page-backed file before parsing build ID

__build_id_parse() only works on page-backed storage.  Its helper paths
eventually call mapping->a_ops->read_folio(), so explicitly reject VMAs
that do not map a regular file or lack valid address_space operations.

Reported-by: syzbot+e008db2ac01e282550ee@...kaller.appspotmail.com
Signed-off-by: Jinchao Wang <wangjinchao600@...il.com>
---
 lib/buildid.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/buildid.c b/lib/buildid.c
index aaf61dfc0919..7131594cb071 100644
--- a/lib/buildid.c
+++ b/lib/buildid.c
@@ -280,7 +280,10 @@ static int __build_id_parse(struct vm_area_struct *vma, unsigned char *build_id,
 	int ret;
 
 	/* only works for page backed storage  */
-	if (!vma->vm_file)
+	if (!vma->vm_file ||
+	    !S_ISREG(file_inode(vma->vm_file)->i_mode) ||
+	    !vma->vm_file->f_mapping->a_ops ||
+	    !vma->vm_file->f_mapping->a_ops->read_folio)
 		return -EINVAL;
 
 	freader_init_from_file(&r, buf, sizeof(buf), vma->vm_file, may_fault);
-- 
2.43.0