From: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp
commit 7c2bd9a39845bfb6d72ddb55ce737650271f6f96 upstream.
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=599993614e7cbbf66bc2656a919ab2a95fb5d75...
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/nfs/super.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -2041,7 +2041,8 @@ static int nfs23_validate_mount_data(voi 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))