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Message-ID: <20200727124127.GO23179@quack2.suse.cz>
Date: Mon, 27 Jul 2020 14:41:27 +0200
From: Jan Kara <jack@...e.cz>
To: Christoph Hellwig <hch@....de>
Cc: x86@...nel.org, Jan Kara <jack@...e.com>,
linux-arm-kernel@...ts.infradead.org,
linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-api@...r.kernel.org, linux-arch@...r.kernel.org
Subject: Re: [PATCH 4/4] quota: simplify the quotactl compat handling
On Sun 26-07-20 18:04:01, Christoph Hellwig wrote:
> Fold the misaligned u64 workarounds into the main quotactl flow instead
> of implementing a separate compat syscall handler.
>
> Signed-off-by: Christoph Hellwig <hch@....de>
The patch looks good to me and it saves a lot of boiler-plate code so feel
free to add:
Acked-by: Jan Kara <jack@...e.cz>
Honza
> ---
> arch/x86/entry/syscalls/syscall_32.tbl | 2 +-
> fs/quota/Kconfig | 5 --
> fs/quota/Makefile | 1 -
> fs/quota/compat.c | 120 -------------------------
> fs/quota/compat.h | 34 +++++++
> fs/quota/quota.c | 73 ++++++++++++---
> include/linux/quotaops.h | 3 -
> kernel/sys_ni.c | 1 -
> 8 files changed, 94 insertions(+), 145 deletions(-)
> delete mode 100644 fs/quota/compat.c
> create mode 100644 fs/quota/compat.h
>
> diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
> index d8f8a1a69ed11f..41d442d7c2db67 100644
> --- a/arch/x86/entry/syscalls/syscall_32.tbl
> +++ b/arch/x86/entry/syscalls/syscall_32.tbl
> @@ -142,7 +142,7 @@
> 128 i386 init_module sys_init_module
> 129 i386 delete_module sys_delete_module
> 130 i386 get_kernel_syms
> -131 i386 quotactl sys_quotactl compat_sys_quotactl32
> +131 i386 quotactl sys_quotactl
> 132 i386 getpgid sys_getpgid
> 133 i386 fchdir sys_fchdir
> 134 i386 bdflush sys_bdflush
> diff --git a/fs/quota/Kconfig b/fs/quota/Kconfig
> index 7218314ca13f00..4f5bb85099a904 100644
> --- a/fs/quota/Kconfig
> +++ b/fs/quota/Kconfig
> @@ -70,8 +70,3 @@ config QFMT_V2
> config QUOTACTL
> bool
> default n
> -
> -config QUOTACTL_COMPAT
> - bool
> - depends on QUOTACTL && COMPAT_FOR_U64_ALIGNMENT
> - default y
> diff --git a/fs/quota/Makefile b/fs/quota/Makefile
> index f2b49d0f0287c9..9160639daffa75 100644
> --- a/fs/quota/Makefile
> +++ b/fs/quota/Makefile
> @@ -4,5 +4,4 @@ obj-$(CONFIG_QFMT_V1) += quota_v1.o
> obj-$(CONFIG_QFMT_V2) += quota_v2.o
> obj-$(CONFIG_QUOTA_TREE) += quota_tree.o
> obj-$(CONFIG_QUOTACTL) += quota.o kqid.o
> -obj-$(CONFIG_QUOTACTL_COMPAT) += compat.o
> obj-$(CONFIG_QUOTA_NETLINK_INTERFACE) += netlink.o
> diff --git a/fs/quota/compat.c b/fs/quota/compat.c
> deleted file mode 100644
> index c305728576193d..00000000000000
> --- a/fs/quota/compat.c
> +++ /dev/null
> @@ -1,120 +0,0 @@
> -// SPDX-License-Identifier: GPL-2.0
> -
> -#include <linux/syscalls.h>
> -#include <linux/compat.h>
> -#include <linux/quotaops.h>
> -
> -/*
> - * 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;
> -};
> -
> -COMPAT_SYSCALL_DEFINE4(quotactl32, 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 = kernel_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 = kernel_quotactl(cmd, special, id, dqblk);
> - break;
> - case Q_XGETQSTAT:
> - fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
> - compat_fsqstat = addr;
> - ret = kernel_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 = kernel_quotactl(cmd, special, id, addr);
> - }
> - return ret;
> -}
> diff --git a/fs/quota/compat.h b/fs/quota/compat.h
> new file mode 100644
> index 00000000000000..ef7d1e12d650b3
> --- /dev/null
> +++ b/fs/quota/compat.h
> @@ -0,0 +1,34 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <linux/compat.h>
> +
> +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;
> +};
> +
> +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;
> +};
> diff --git a/fs/quota/quota.c b/fs/quota/quota.c
> index 5444d3c4d93f37..e1e9d05a14c3e4 100644
> --- a/fs/quota/quota.c
> +++ b/fs/quota/quota.c
> @@ -19,6 +19,7 @@
> #include <linux/types.h>
> #include <linux/writeback.h>
> #include <linux/nospec.h>
> +#include "compat.h"
>
> static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
> qid_t id)
> @@ -211,8 +212,18 @@ static int quota_getquota(struct super_block *sb, int type, qid_t id,
> if (ret)
> return ret;
> copy_to_if_dqblk(&idq, &fdq);
> - if (copy_to_user(addr, &idq, sizeof(idq)))
> - return -EFAULT;
> +
> + if (compat_need_64bit_alignment_fixup()) {
> + struct compat_if_dqblk __user *compat_dqblk = addr;
> +
> + if (copy_to_user(compat_dqblk, &idq, sizeof(*compat_dqblk)))
> + return -EFAULT;
> + if (put_user(idq.dqb_valid, &compat_dqblk->dqb_valid))
> + return -EFAULT;
> + } else {
> + if (copy_to_user(addr, &idq, sizeof(idq)))
> + return -EFAULT;
> + }
> return 0;
> }
>
> @@ -277,8 +288,16 @@ static int quota_setquota(struct super_block *sb, int type, qid_t id,
> struct if_dqblk idq;
> struct kqid qid;
>
> - if (copy_from_user(&idq, addr, sizeof(idq)))
> - return -EFAULT;
> + if (compat_need_64bit_alignment_fixup()) {
> + struct compat_if_dqblk __user *compat_dqblk = addr;
> +
> + if (copy_from_user(&idq, compat_dqblk, sizeof(*compat_dqblk)) ||
> + get_user(idq.dqb_valid, &compat_dqblk->dqb_valid))
> + return -EFAULT;
> + } else {
> + if (copy_from_user(&idq, addr, sizeof(idq)))
> + return -EFAULT;
> + }
> if (!sb->s_qcop->set_dqblk)
> return -ENOSYS;
> qid = make_kqid(current_user_ns(), type, id);
> @@ -382,6 +401,33 @@ static int quota_getstate(struct super_block *sb, int type,
> return 0;
> }
>
> +static int compat_copy_fs_qfilestat(struct compat_fs_qfilestat __user *to,
> + struct fs_qfilestat *from)
> +{
> + if (copy_to_user(to, from, sizeof(*to)) ||
> + put_user(from->qfs_nextents, &to->qfs_nextents))
> + return -EFAULT;
> + return 0;
> +}
> +
> +static int compat_copy_fs_quota_stat(struct compat_fs_quota_stat __user *to,
> + struct fs_quota_stat *from)
> +{
> + if (put_user(from->qs_version, &to->qs_version) ||
> + put_user(from->qs_flags, &to->qs_flags) ||
> + put_user(from->qs_pad, &to->qs_pad) ||
> + compat_copy_fs_qfilestat(&to->qs_uquota, &from->qs_uquota) ||
> + compat_copy_fs_qfilestat(&to->qs_gquota, &from->qs_gquota) ||
> + put_user(from->qs_incoredqs, &to->qs_incoredqs) ||
> + put_user(from->qs_btimelimit, &to->qs_btimelimit) ||
> + put_user(from->qs_itimelimit, &to->qs_itimelimit) ||
> + put_user(from->qs_rtbtimelimit, &to->qs_rtbtimelimit) ||
> + put_user(from->qs_bwarnlimit, &to->qs_bwarnlimit) ||
> + put_user(from->qs_iwarnlimit, &to->qs_iwarnlimit))
> + return -EFAULT;
> + return 0;
> +}
> +
> static int quota_getxstate(struct super_block *sb, int type, void __user *addr)
> {
> struct fs_quota_stat fqs;
> @@ -390,9 +436,14 @@ static int quota_getxstate(struct super_block *sb, int type, void __user *addr)
> if (!sb->s_qcop->get_state)
> return -ENOSYS;
> ret = quota_getstate(sb, type, &fqs);
> - if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
> + if (ret)
> + return ret;
> +
> + if (compat_need_64bit_alignment_fixup())
> + return compat_copy_fs_quota_stat(addr, &fqs);
> + if (copy_to_user(addr, &fqs, sizeof(fqs)))
> return -EFAULT;
> - return ret;
> + return 0;
> }
>
> static int quota_getstatev(struct super_block *sb, int type,
> @@ -816,8 +867,8 @@ static struct super_block *quotactl_block(const char __user *special, int cmd)
> * calls. Maybe we need to add the process quotas etc. in the future,
> * but we probably should use rlimits for that.
> */
> -int kernel_quotactl(unsigned int cmd, const char __user *special,
> - qid_t id, void __user *addr)
> +SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
> + qid_t, id, void __user *, addr)
> {
> uint cmds, type;
> struct super_block *sb = NULL;
> @@ -871,9 +922,3 @@ int kernel_quotactl(unsigned int cmd, const char __user *special,
> path_put(pathp);
> return ret;
> }
> -
> -SYSCALL_DEFINE4(quotactl, unsigned int, cmd, const char __user *, special,
> - qid_t, id, void __user *, addr)
> -{
> - return kernel_quotactl(cmd, special, id, addr);
> -}
> diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
> index 9cf0cd3dc88c68..a0f6668924d3ef 100644
> --- a/include/linux/quotaops.h
> +++ b/include/linux/quotaops.h
> @@ -27,9 +27,6 @@ static inline bool is_quota_modification(struct inode *inode, struct iattr *ia)
> (ia->ia_valid & ATTR_GID && !gid_eq(ia->ia_gid, inode->i_gid));
> }
>
> -int kernel_quotactl(unsigned int cmd, const char __user *special,
> - qid_t id, void __user *addr);
> -
> #if defined(CONFIG_QUOTA)
>
> #define quota_error(sb, fmt, args...) \
> diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
> index 3b69a560a7ac56..f01b91cc57fa00 100644
> --- a/kernel/sys_ni.c
> +++ b/kernel/sys_ni.c
> @@ -370,7 +370,6 @@ COND_SYSCALL_COMPAT(fanotify_mark);
> /* x86 */
> COND_SYSCALL(vm86old);
> COND_SYSCALL(modify_ldt);
> -COND_SYSCALL_COMPAT(quotactl32);
> COND_SYSCALL(vm86);
> COND_SYSCALL(kexec_file_load);
>
> --
> 2.27.0
>
--
Jan Kara <jack@...e.com>
SUSE Labs, CR
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