Commit b716395e authored by Vasily Tarasov's avatar Vasily Tarasov Committed by Linus Torvalds
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diskquota: 32bit quota tools on 64bit architectures 



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: default avatarVasily 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: default avatarMichal Piotrowski <michal.k.k.piotrowski@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4b777587

arch/ia64/ia32/ia32_entry.S

+1 −1
Original line number Diff line number Diff line
@@ -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 */

arch/x86_64/ia32/ia32entry.S

+1 −1
Original line number Diff line number Diff line
@@ -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 */

fs/quota.c

+118 −0
Original line number Diff line number Diff line
@@ -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

kernel/sys_ni.c

+1 −0
Original line number Diff line number Diff line
@@ -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);

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