2006-05-11 06:22:59

by Lin Feng Shen

[permalink] [raw]
Subject: [PATCH 1/1] NFS: fix error handling on access_ok in compat_sys_nfsservctl

From: Lin Feng Shen <[email protected]>

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 <[email protected]>
---

--- 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)
{
- 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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2006-05-12 03:29:13

by Arthur Othieno

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

On Thu, May 11, 2006 at 02:22:14PM +0800, Lin Feng Shen wrote:
> From: Lin Feng Shen <[email protected]>
>
> 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 <[email protected]>
> ---
>
> --- 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