linux-kernel - [PATCH v2 09/10] bpf: Add size validation to bpf_sock_addr_set_sun

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

Message-Id: <20251014224334.2344521-9-kees@kernel.org>
Date: Tue, 14 Oct 2025 15:43:31 -0700
From: Kees Cook <kees@...nel.org>
To: Jakub Kicinski <kuba@...nel.org>
Cc: Kees Cook <kees@...nel.org>,
	"Gustavo A. R. Silva" <gustavo@...eddedor.com>,
	Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	John Fastabend <john.fastabend@...il.com>,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Paolo Abeni <pabeni@...hat.com>,
	Simon Horman <horms@...nel.org>,
	Kuniyuki Iwashima <kuniyu@...gle.com>,
	Willem de Bruijn <willemb@...gle.com>,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	bpf@...r.kernel.org,
	linux-hardening@...r.kernel.org
Subject: [PATCH v2 09/10] bpf: Add size validation to bpf_sock_addr_set_sun_path()

Add defensive size validation to bpf_sock_addr_set_sun_path() before
writing to the sockaddr buffer. While the underlying buffer is guaranteed
to be sockaddr_storage (128 bytes) from the bind() syscall path, the
function should validate that "sa_kern->uaddrlen" is sufficient for the
sockaddr_un structure being written.

The validation checks that the available buffer size ("sa_kern->uaddrlen")
can accommodate both the sockaddr_un header and the requested path length
before performing the memcpy() operation.

Signed-off-by: Kees Cook <kees@...nel.org>
---
 net/core/filter.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/net/core/filter.c b/net/core/filter.c
index b96b5ffc7eb3..fa6c5baf0bf3 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -12089,6 +12089,7 @@ __bpf_kfunc int bpf_sock_addr_set_sun_path(struct bpf_sock_addr_kern *sa_kern,
 					   const u8 *sun_path, u32 sun_path__sz)
 {
 	struct sockaddr_un *un;
+	size_t required_size;
 
 	if (sa_kern->sk->sk_family != AF_UNIX)
 		return -EINVAL;
@@ -12099,9 +12100,14 @@ __bpf_kfunc int bpf_sock_addr_set_sun_path(struct bpf_sock_addr_kern *sa_kern,
 	if (sun_path__sz == 0 || sun_path__sz > UNIX_PATH_MAX)
 		return -EINVAL;
 
+	/* Validate that the buffer is large enough for sockaddr_un + path */
+	required_size = offsetof(struct sockaddr_un, sun_path) + sun_path__sz;
+	if (sa_kern->uaddrlen < required_size)
+		return -EINVAL;
+
 	un = (struct sockaddr_un *)sa_kern->uaddr;
 	memcpy(un->sun_path, sun_path, sun_path__sz);
-	sa_kern->uaddrlen = offsetof(struct sockaddr_un, sun_path) + sun_path__sz;
+	sa_kern->uaddrlen = required_size;
 
 	return 0;
 }
-- 
2.34.1