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io_uring/net: mask socket type with SOCK_TYPE_MASK in io_socket_bpf_populate()

PATCH Applied Dominik Maier 2 participants 2 messages Oct 22 – Oct 26 io_uring

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PATCH 1/1 io_uring/net: mask socket type with SOCK_TYPE_MASK in io_socket_bpf_populate()

When an IORING_OP_SOCKET request is prepared in io_socket_prep(), sock->type retains creation flags such as SOCK_CLOEXEC and SOCK_NONBLOCK until __sys_socket_file() masks them off with SOCK_TYPE_MASK during execution.

However, io_socket_bpf_populate() copies sock->type into bctx->socket.type without masking off ~SOCK_TYPE_MASK. As a result, a cBPF filter inspecting bctx->socket.type against socket types such as SOCK_DGRAM or SOCK_STREAM can be bypassed by ORing SOCK_CLOEXEC or SOCK_NONBLOCK into the socket type.

Mask sock->type with SOCK_TYPE_MASK when populating bctx->socket.type.

Fixes cff1c26b4223 ("io_uring/net: allow filtering on IORING_OP_SOCKET data")
Assisted-by ARTIST LLM
---
 io_uring/net.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
io_uring/net.c +1 -1
index f5f4f3ce6ef3..5ead8a83a89f 100644
@@ -1711,7 +1711,7 @@ void io_socket_bpf_populate(struct io_uring_bpf_ctx *bctx, struct io_kiocb *req)
 	struct io_socket *sock = io_kiocb_to_cmd(req, struct io_socket);
 
 	bctx->socket.family = sock->domain;
-	bctx->socket.type = sock->type;
+	bctx->socket.type = sock->type & SOCK_TYPE_MASK;
 	bctx->socket.protocol = sock->protocol;
 }
 
Signature · 1 line
2.56.0.257.gf7497c7d27-goog
maintainer Applied
#1 lore raw
Quoted 5 lines · Dominik Maier

When an IORING_OP_SOCKET request is prepared in io_socket_prep(), sock->type retains creation flags such as SOCK_CLOEXEC and SOCK_NONBLOCK until __sys_socket_file() masks them off with SOCK_TYPE_MASK during execution.

Quoted 7 lines

However, io_socket_bpf_populate() copies sock->type into bctx->socket.type without masking off ~SOCK_TYPE_MASK. As a result, a cBPF filter inspecting bctx->socket.type against socket types such as SOCK_DGRAM or SOCK_STREAM can be bypassed by ORing SOCK_CLOEXEC or SOCK_NONBLOCK into the socket type.

[...]

Applied, thanks!

[1/1] io_uring/net: mask socket type with SOCK_TYPE_MASK in io_socket_bpf_populate()

      commit: e66907c3ba229399ecfb4ef032b95a4a071c894e

Best regards,

Signature · 1 line
Jens Axboe