Re: [PATCH 1/1] NFS: fix error handling on access_ok in compat_sys_nfsservctl

[Arthur Othieno]

On Thu, May 11, 2006 at 02:22:14PM +0800, Lin Feng Shen wrote:
> From: Lin Feng Shen <shenlinf@xxxxxxxxxx>
> 
> Functions compat_nfs_svc_trans, compat_nfs_clnt_trans, compat_nfs_exp_trans,
> compat_nfs_getfd_trans and compat_nfs_getfs_trans, which are called by
> compat_sys_nfsservctl(fs/compat.c), don't handle the return value of
> access_ok properly. access_ok return 1 when the addr is valid, and 0
> when it's not, but these functions have the reversed understanding. When the
> address is valid, they always return -EFAULT to compat_sys_nfsservctl.
> 
> An example is to run /usr/sbin/rpc.nfsd(32bit program on Power5). It doesn't
> function as expected. strace showes that nfsservctl returns -EFAULT.
> 
> The patch fixes this by correcting the error handling on the return value of
> access_ok in the five functions. It is created against 
> linux-2.6.17-rc3-git16.
> 
> Signed-off-by: Lin Feng Shen <shenlinf@xxxxxxxxxx>
> ---
> 
> --- linux-2.6.17-rc3-git16/fs/compat.c.orig    2006-05-09 
> 09:07:38.000000000 -0500
> +++ linux-2.6.17-rc3-git16/fs/compat.c    2006-05-09 09:21:00.000000000 
> -0500
> @@ -2032,101 +2032,96 @@ union compat_nfsctl_res {
> 
> static int compat_nfs_svc_trans(struct nfsctl_arg *karg, struct 
> compat_nfsctl_arg __user *arg)

Your client is happily munging whitespace all over:

  patching file fs/compat.c
  patch: **** malformed patch at line 25: compat_nfsctl_arg __user *arg)

> {
> -    int err;
> -
> -    err = access_ok(VERIFY_READ, &arg->ca32_svc, sizeof(arg->ca32_svc));
> -    err |= get_user(karg->ca_version, &arg->ca32_version);
> -    err |= __get_user(karg->ca_svc.svc_port, &arg->ca32_svc.svc32_port);
> -    err |= __get_user(karg->ca_svc.svc_nthreads, 
> &arg->ca32_svc.svc32_nthreads);
> -    return (err) ? -EFAULT : 0;
> +    if(!access_ok(VERIFY_READ, &arg->ca32_svc, sizeof(arg->ca32_svc)) ||
> +        get_user(karg->ca_version, &arg->ca32_version) ||
> +        __get_user(karg->ca_svc.svc_port, &arg->ca32_svc.svc32_port) ||
> +        __get_user(karg->ca_svc.svc_nthreads, 
> &arg->ca32_svc.svc32_nthreads))
> +        return -EFAULT;
> +    return 0;
> }
> 
> static int compat_nfs_clnt_trans(struct nfsctl_arg *karg, struct 
> compat_nfsctl_arg __user *arg)
> {
> -    int err;
> -
> -    err = access_ok(VERIFY_READ, &arg->ca32_client, 
> sizeof(arg->ca32_client));
> -    err |= get_user(karg->ca_version, &arg->ca32_version);
> -    err |= __copy_from_user(&karg->ca_client.cl_ident[0],
> +    if(!access_ok(VERIFY_READ, &arg->ca32_client, 
> sizeof(arg->ca32_client)) ||
> +        get_user(karg->ca_version, &arg->ca32_version) ||
> +        __copy_from_user(&karg->ca_client.cl_ident[0],
>               &arg->ca32_client.cl32_ident[0],
> -              NFSCLNT_IDMAX);
> -    err |= __get_user(karg->ca_client.cl_naddr, 
> &arg->ca32_client.cl32_naddr);
> -    err |= __copy_from_user(&karg->ca_client.cl_addrlist[0],
> +              NFSCLNT_IDMAX) ||
> +        __get_user(karg->ca_client.cl_naddr, 
> &arg->ca32_client.cl32_naddr) ||
> +        __copy_from_user(&karg->ca_client.cl_addrlist[0],
>               &arg->ca32_client.cl32_addrlist[0],
> -              (sizeof(struct in_addr) * NFSCLNT_ADDRMAX));
> -    err |= __get_user(karg->ca_client.cl_fhkeytype,
> -              &arg->ca32_client.cl32_fhkeytype);
> -    err |= __get_user(karg->ca_client.cl_fhkeylen,
> -              &arg->ca32_client.cl32_fhkeylen);
> -    err |= __copy_from_user(&karg->ca_client.cl_fhkey[0],
> +              (sizeof(struct in_addr) * NFSCLNT_ADDRMAX)) ||
> +        __get_user(karg->ca_client.cl_fhkeytype,
> +              &arg->ca32_client.cl32_fhkeytype) ||
> +        __get_user(karg->ca_client.cl_fhkeylen,
> +              &arg->ca32_client.cl32_fhkeylen) ||
> +        __copy_from_user(&karg->ca_client.cl_fhkey[0],
>               &arg->ca32_client.cl32_fhkey[0],
> -              NFSCLNT_KEYMAX);
> +              NFSCLNT_KEYMAX))
> +        return -EFAULT;
> 
> -    return (err) ? -EFAULT : 0;
> +    return 0;
> }
> 
> static int compat_nfs_exp_trans(struct nfsctl_arg *karg, struct 
> compat_nfsctl_arg __user *arg)
> {
> -    int err;
> -
> -    err = access_ok(VERIFY_READ, &arg->ca32_export, 
> sizeof(arg->ca32_export));
> -    err |= get_user(karg->ca_version, &arg->ca32_version);
> -    err |= __copy_from_user(&karg->ca_export.ex_client[0],
> +    if(!access_ok(VERIFY_READ, &arg->ca32_export, 
> sizeof(arg->ca32_export)) ||
> +        get_user(karg->ca_version, &arg->ca32_version) ||
> +        __copy_from_user(&karg->ca_export.ex_client[0],
>               &arg->ca32_export.ex32_client[0],
> -              NFSCLNT_IDMAX);
> -    err |= __copy_from_user(&karg->ca_export.ex_path[0],
> +              NFSCLNT_IDMAX) ||
> +        __copy_from_user(&karg->ca_export.ex_path[0],
>               &arg->ca32_export.ex32_path[0],
> -              NFS_MAXPATHLEN);
> -    err |= __get_user(karg->ca_export.ex_dev,
> -              &arg->ca32_export.ex32_dev);
> -    err |= __get_user(karg->ca_export.ex_ino,
> -              &arg->ca32_export.ex32_ino);
> -    err |= __get_user(karg->ca_export.ex_flags,
> -              &arg->ca32_export.ex32_flags);
> -    err |= __get_user(karg->ca_export.ex_anon_uid,
> -              &arg->ca32_export.ex32_anon_uid);
> -    err |= __get_user(karg->ca_export.ex_anon_gid,
> -              &arg->ca32_export.ex32_anon_gid);
> +              NFS_MAXPATHLEN) ||
> +        __get_user(karg->ca_export.ex_dev,
> +              &arg->ca32_export.ex32_dev) ||
> +        __get_user(karg->ca_export.ex_ino,
> +              &arg->ca32_export.ex32_ino) ||
> +        __get_user(karg->ca_export.ex_flags,
> +              &arg->ca32_export.ex32_flags) ||
> +        __get_user(karg->ca_export.ex_anon_uid,
> +              &arg->ca32_export.ex32_anon_uid) ||
> +        __get_user(karg->ca_export.ex_anon_gid,
> +              &arg->ca32_export.ex32_anon_gid))
> +        return -EFAULT;
>     SET_UID(karg->ca_export.ex_anon_uid, karg->ca_export.ex_anon_uid);
>     SET_GID(karg->ca_export.ex_anon_gid, karg->ca_export.ex_anon_gid);
> 
> -    return (err) ? -EFAULT : 0;
> +    return 0;
> }
> 
> static int compat_nfs_getfd_trans(struct nfsctl_arg *karg, struct 
> compat_nfsctl_arg __user *arg)
> {
> -    int err;
> -
> -    err = access_ok(VERIFY_READ, &arg->ca32_getfd, 
> sizeof(arg->ca32_getfd));
> -    err |= get_user(karg->ca_version, &arg->ca32_version);
> -    err |= __copy_from_user(&karg->ca_getfd.gd_addr,
> +    if(!access_ok(VERIFY_READ, &arg->ca32_getfd, 
> sizeof(arg->ca32_getfd)) ||
> +        get_user(karg->ca_version, &arg->ca32_version) ||
> +        __copy_from_user(&karg->ca_getfd.gd_addr,
>               &arg->ca32_getfd.gd32_addr,
> -              (sizeof(struct sockaddr)));
> -    err |= __copy_from_user(&karg->ca_getfd.gd_path,
> +              (sizeof(struct sockaddr))) ||
> +        __copy_from_user(&karg->ca_getfd.gd_path,
>               &arg->ca32_getfd.gd32_path,
> -              (NFS_MAXPATHLEN+1));
> -    err |= __get_user(karg->ca_getfd.gd_version,
> -              &arg->ca32_getfd.gd32_version);
> +              (NFS_MAXPATHLEN+1)) ||
> +        __get_user(karg->ca_getfd.gd_version,
> +              &arg->ca32_getfd.gd32_version))
> +        return -EFAULT;
> 
> -    return (err) ? -EFAULT : 0;
> +    return 0;
> }
> 
> static int compat_nfs_getfs_trans(struct nfsctl_arg *karg, struct 
> compat_nfsctl_arg __user *arg)
> {
> -    int err;
> -
> -    err = access_ok(VERIFY_READ, &arg->ca32_getfs, 
> sizeof(arg->ca32_getfs));
> -    err |= get_user(karg->ca_version, &arg->ca32_version);
> -    err |= __copy_from_user(&karg->ca_getfs.gd_addr,
> +    if(!access_ok(VERIFY_READ, &arg->ca32_getfs, 
> sizeof(arg->ca32_getfs)) ||
> +        get_user(karg->ca_version, &arg->ca32_version) ||
> +        __copy_from_user(&karg->ca_getfs.gd_addr,
>               &arg->ca32_getfs.gd32_addr,
> -              (sizeof(struct sockaddr)));
> -    err |= __copy_from_user(&karg->ca_getfs.gd_path,
> +              (sizeof(struct sockaddr))) ||
> +        __copy_from_user(&karg->ca_getfs.gd_path,
>               &arg->ca32_getfs.gd32_path,
> -              (NFS_MAXPATHLEN+1));
> -    err |= __get_user(karg->ca_getfs.gd_maxlen,
> -              &arg->ca32_getfs.gd32_maxlen);
> +              (NFS_MAXPATHLEN+1)) ||
> +        __get_user(karg->ca_getfs.gd_maxlen,
> +              &arg->ca32_getfs.gd32_maxlen))
> +        return -EFAULT;
> 
> -    return (err) ? -EFAULT : 0;
> +    return 0;
> }
> 
> /* This really doesn't need translations, we are only passing
-
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