Commit 7c2bd9a3 authored Mar 30, 2019 by Tetsuo Handa Committed by Trond Myklebust Apr 11, 2019

NFS: Forbid setting AF_INET6 to "struct sockaddr_in"->sin_family.

syzbot is reporting uninitialized value at rpc_sockaddr2uaddr() [1]. This
is because syzbot is setting AF_INET6 to "struct sockaddr_in"->sin_family
(which is embedded into user-visible "struct nfs_mount_data" structure)
despite nfs23_validate_mount_data() cannot pass sizeof(struct sockaddr_in6)
bytes of AF_INET6 address to rpc_sockaddr2uaddr().

Since "struct nfs_mount_data" structure is user-visible, we can't change
"struct nfs_mount_data" to use "struct sockaddr_storage". Therefore,
assuming that everybody is using AF_INET family when passing address via
"struct nfs_mount_data"->addr, reject if its sin_family is not AF_INET.

[1] https://syzkaller.appspot.com/bug?id=599993614e7cbbf66bc2656a919ab2a95fb5d75c



Reported-by: syzbot <syzbot+047a11c361b872896a4f@syzkaller.appspotmail.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

parent 582549e3

fs/nfs/super.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -2041,7 +2041,8 @@ static int nfs23_validate_mount_data(void *options,
		memcpy(sap, &data->addr, sizeof(data->addr));
		args->nfs_server.addrlen = sizeof(data->addr);
		args->nfs_server.port = ntohs(data->addr.sin_port);
		if (!nfs_verify_server_address(sap))
		if (sap->sa_family != AF_INET \|\|
		!nfs_verify_server_address(sap))
		goto out_no_address;

		if (!(data->flags & NFS_MOUNT_TCP))

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