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diskquota: 32bit quota tools on 64bit architectures

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OpenVZ Linux kernel team has discovered the problem with 32bit quota tools
working on 64bit architectures.  In 2.6.10 kernel sys32_quotactl() function
was replaced by sys_quotactl() with the comment "sys_quotactl seems to be
32/64bit clean, enable it for 32bit" However this isn't right.  Look at
if_dqblk structure:

struct if_dqblk {
        __u64 dqb_bhardlimit;
        __u64 dqb_bsoftlimit;
        __u64 dqb_curspace;
        __u64 dqb_ihardlimit;
        __u64 dqb_isoftlimit;
        __u64 dqb_curinodes;
        __u64 dqb_btime;
        __u64 dqb_itime;
        __u32 dqb_valid;
};

For 32 bit quota tools sizeof(if_dqblk) == 0x44.
But for 64 bit kernel its size is 0x48, 'cause of alignment!
Thus we got a problem. Attached patch reintroduce sys32_quotactl() function,
that handles this and related situations.

[michal.k.k.piotrowski@gmail.com: build fix]
[akpm@linux-foundation.org: Make it link with CONFIG_QUOTA=n]
Signed-off-by: Vasily Tarasov <vtaras@openvz.org>
Cc: Andi Kleen <ak@suse.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Vasily Tarasov 2007-07-15 23:41:12 -07:00 committed by Linus Torvalds
parent 4b7775870b
commit b716395e2b
4 changed files with 121 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
arch/ia64/ia32/ia32_entry.S
View file

@ -304,7 +304,7 @@ ia32_syscall_table:
data8 sys_ni_syscall /* init_module */
data8 sys_ni_syscall /* delete_module */
data8 sys_ni_syscall /* get_kernel_syms */ /* 130 */
data8 sys_quotactl
data8 sys32_quotactl
data8 sys_getpgid
data8 sys_fchdir
data8 sys_ni_syscall /* sys_bdflush */

2
arch/x86_64/ia32/ia32entry.S
View file

@ -526,7 +526,7 @@ ia32_sys_call_table:
.quad sys_init_module
.quad sys_delete_module
.quad quiet_ni_syscall /* 130 get_kernel_syms */
.quad sys_quotactl
.quad sys32_quotactl
.quad sys_getpgid
.quad sys_fchdir
.quad quiet_ni_syscall /* bdflush */

118
fs/quota.c
View file

@ -10,12 +10,14 @@
#include <linux/slab.h>
#include <asm/current.h>
#include <asm/uaccess.h>
#include <linux/compat.h>
#include <linux/kernel.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/buffer_head.h>
#include <linux/capability.h>
#include <linux/quotaops.h>
#include <linux/types.h>
/* Check validity of generic quotactl commands */
static int generic_quotactl_valid(struct super_block *sb, int type, int cmd, qid_t id)
@ -384,3 +386,119 @@ asmlinkage long sys_quotactl(unsigned int cmd, const char __user *special, qid_t
return ret;
}
#if defined(CONFIG_X86_64) || defined(CONFIG_IA64)
/*
* This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
* and is necessary due to alignment problems.
*/
struct compat_if_dqblk {
compat_u64 dqb_bhardlimit;
compat_u64 dqb_bsoftlimit;
compat_u64 dqb_curspace;
compat_u64 dqb_ihardlimit;
compat_u64 dqb_isoftlimit;
compat_u64 dqb_curinodes;
compat_u64 dqb_btime;
compat_u64 dqb_itime;
compat_uint_t dqb_valid;
};
/* XFS structures */
struct compat_fs_qfilestat {
compat_u64 dqb_bhardlimit;
compat_u64 qfs_nblks;
compat_uint_t qfs_nextents;
};
struct compat_fs_quota_stat {
__s8 qs_version;
__u16 qs_flags;
__s8 qs_pad;
struct compat_fs_qfilestat qs_uquota;
struct compat_fs_qfilestat qs_gquota;
compat_uint_t qs_incoredqs;
compat_int_t qs_btimelimit;
compat_int_t qs_itimelimit;
compat_int_t qs_rtbtimelimit;
__u16 qs_bwarnlimit;
__u16 qs_iwarnlimit;
};
asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
qid_t id, void __user *addr)
{
unsigned int cmds;
struct if_dqblk __user *dqblk;
struct compat_if_dqblk __user *compat_dqblk;
struct fs_quota_stat __user *fsqstat;
struct compat_fs_quota_stat __user *compat_fsqstat;
compat_uint_t data;
u16 xdata;
long ret;
cmds = cmd >> SUBCMDSHIFT;
switch (cmds) {
case Q_GETQUOTA:
dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
compat_dqblk = addr;
ret = sys_quotactl(cmd, special, id, dqblk);
if (ret)
break;
if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
get_user(data, &dqblk->dqb_valid) ||
put_user(data, &compat_dqblk->dqb_valid))
ret = -EFAULT;
break;
case Q_SETQUOTA:
dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
compat_dqblk = addr;
ret = -EFAULT;
if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
get_user(data, &compat_dqblk->dqb_valid) ||
put_user(data, &dqblk->dqb_valid))
break;
ret = sys_quotactl(cmd, special, id, dqblk);
break;
case Q_XGETQSTAT:
fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
compat_fsqstat = addr;
ret = sys_quotactl(cmd, special, id, fsqstat);
if (ret)
break;
ret = -EFAULT;
/* Copying qs_version, qs_flags, qs_pad */
if (copy_in_user(compat_fsqstat, fsqstat,
offsetof(struct compat_fs_quota_stat, qs_uquota)))
break;
/* Copying qs_uquota */
if (copy_in_user(&compat_fsqstat->qs_uquota,
&fsqstat->qs_uquota,
sizeof(compat_fsqstat->qs_uquota)) ||
get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
break;
/* Copying qs_gquota */
if (copy_in_user(&compat_fsqstat->qs_gquota,
&fsqstat->qs_gquota,
sizeof(compat_fsqstat->qs_gquota)) ||
get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
break;
/* Copying the rest */
if (copy_in_user(&compat_fsqstat->qs_incoredqs,
&fsqstat->qs_incoredqs,
sizeof(struct compat_fs_quota_stat) -
offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
get_user(xdata, &fsqstat->qs_iwarnlimit) ||
put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
break;
ret = 0;
break;
default:
ret = sys_quotactl(cmd, special, id, addr);
}
return ret;
}
#endif

1
kernel/sys_ni.c
View file

@ -14,6 +14,7 @@ asmlinkage long sys_ni_syscall(void)
cond_syscall(sys_nfsservctl);
cond_syscall(sys_quotactl);
cond_syscall(sys32_quotactl);
cond_syscall(sys_acct);
cond_syscall(sys_lookup_dcookie);
cond_syscall(sys_swapon);