From 42a74f206b914db13ee1f5ae932dcd91a77c8579 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Fri, 15 Feb 2008 14:37:46 -0800 Subject: [PATCH] r/o bind mounts: elevate write count for ioctls() Some ioctl()s can cause writes to the filesystem. Take these, and make them use mnt_want/drop_write() instead. [AV: updated] Acked-by: Al Viro Signed-off-by: Christoph Hellwig Signed-off-by: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Al Viro --- fs/ext4/ioctl.c | 86 ++++++++++++++++++++++++++++++++------------------------- 1 file changed, 49 insertions(+), 37 deletions(-) (limited to 'fs/ext4/ioctl.c') diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index 2ed7c37f897..25b13ede808 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -15,6 +15,7 @@ #include #include #include +#include #include int ext4_ioctl (struct inode * inode, struct file * filp, unsigned int cmd, @@ -38,24 +39,25 @@ int ext4_ioctl (struct inode * inode, struct file * filp, unsigned int cmd, unsigned int oldflags; unsigned int jflag; - if (IS_RDONLY(inode)) - return -EROFS; - if (!is_owner_or_cap(inode)) return -EACCES; if (get_user(flags, (int __user *) arg)) return -EFAULT; + err = mnt_want_write(filp->f_path.mnt); + if (err) + return err; + if (!S_ISDIR(inode->i_mode)) flags &= ~EXT4_DIRSYNC_FL; + err = -EPERM; mutex_lock(&inode->i_mutex); /* Is it quota file? Do not allow user to mess with it */ - if (IS_NOQUOTA(inode)) { - mutex_unlock(&inode->i_mutex); - return -EPERM; - } + if (IS_NOQUOTA(inode)) + goto flags_out; + oldflags = ei->i_flags; /* The JOURNAL_DATA flag is modifiable only by root */ @@ -68,10 +70,8 @@ int ext4_ioctl (struct inode * inode, struct file * filp, unsigned int cmd, * This test looks nicer. Thanks to Pauline Middelink */ if ((flags ^ oldflags) & (EXT4_APPEND_FL | EXT4_IMMUTABLE_FL)) { - if (!capable(CAP_LINUX_IMMUTABLE)) { - mutex_unlock(&inode->i_mutex); - return -EPERM; - } + if (!capable(CAP_LINUX_IMMUTABLE)) + goto flags_out; } /* @@ -79,17 +79,14 @@ int ext4_ioctl (struct inode * inode, struct file * filp, unsigned int cmd, * the relevant capability. */ if ((jflag ^ oldflags) & (EXT4_JOURNAL_DATA_FL)) { - if (!capable(CAP_SYS_RESOURCE)) { - mutex_unlock(&inode->i_mutex); - return -EPERM; - } + if (!capable(CAP_SYS_RESOURCE)) + goto flags_out; } - handle = ext4_journal_start(inode, 1); if (IS_ERR(handle)) { - mutex_unlock(&inode->i_mutex); - return PTR_ERR(handle); + err = PTR_ERR(handle); + goto flags_out; } if (IS_SYNC(inode)) handle->h_sync = 1; @@ -107,14 +104,14 @@ int ext4_ioctl (struct inode * inode, struct file * filp, unsigned int cmd, err = ext4_mark_iloc_dirty(handle, inode, &iloc); flags_err: ext4_journal_stop(handle); - if (err) { - mutex_unlock(&inode->i_mutex); - return err; - } + if (err) + goto flags_out; if ((jflag ^ oldflags) & (EXT4_JOURNAL_DATA_FL)) err = ext4_change_inode_journal_flag(inode, jflag); +flags_out: mutex_unlock(&inode->i_mutex); + mnt_drop_write(filp->f_path.mnt); return err; } case EXT4_IOC_GETVERSION: @@ -129,14 +126,20 @@ flags_err: if (!is_owner_or_cap(inode)) return -EPERM; - if (IS_RDONLY(inode)) - return -EROFS; - if (get_user(generation, (int __user *) arg)) - return -EFAULT; + + err = mnt_want_write(filp->f_path.mnt); + if (err) + return err; + if (get_user(generation, (int __user *) arg)) { + err = -EFAULT; + goto setversion_out; + } handle = ext4_journal_start(inode, 1); - if (IS_ERR(handle)) - return PTR_ERR(handle); + if (IS_ERR(handle)) { + err = PTR_ERR(handle); + goto setversion_out; + } err = ext4_reserve_inode_write(handle, inode, &iloc); if (err == 0) { inode->i_ctime = ext4_current_time(inode); @@ -144,6 +147,8 @@ flags_err: err = ext4_mark_iloc_dirty(handle, inode, &iloc); } ext4_journal_stop(handle); +setversion_out: + mnt_drop_write(filp->f_path.mnt); return err; } #ifdef CONFIG_JBD2_DEBUG @@ -179,19 +184,21 @@ flags_err: } return -ENOTTY; case EXT4_IOC_SETRSVSZ: { + int err; if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode)) return -ENOTTY; - if (IS_RDONLY(inode)) - return -EROFS; - if (!is_owner_or_cap(inode)) return -EACCES; if (get_user(rsv_window_size, (int __user *)arg)) return -EFAULT; + err = mnt_want_write(filp->f_path.mnt); + if (err) + return err; + if (rsv_window_size > EXT4_MAX_RESERVE_BLOCKS) rsv_window_size = EXT4_MAX_RESERVE_BLOCKS; @@ -208,6 +215,7 @@ flags_err: rsv->rsv_goal_size = rsv_window_size; } up_write(&ei->i_data_sem); + mnt_drop_write(filp->f_path.mnt); return 0; } case EXT4_IOC_GROUP_EXTEND: { @@ -218,16 +226,18 @@ flags_err: if (!capable(CAP_SYS_RESOURCE)) return -EPERM; - if (IS_RDONLY(inode)) - return -EROFS; - if (get_user(n_blocks_count, (__u32 __user *)arg)) return -EFAULT; + err = mnt_want_write(filp->f_path.mnt); + if (err) + return err; + err = ext4_group_extend(sb, EXT4_SB(sb)->s_es, n_blocks_count); jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal); jbd2_journal_flush(EXT4_SB(sb)->s_journal); jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal); + mnt_drop_write(filp->f_path.mnt); return err; } @@ -239,17 +249,19 @@ flags_err: if (!capable(CAP_SYS_RESOURCE)) return -EPERM; - if (IS_RDONLY(inode)) - return -EROFS; - if (copy_from_user(&input, (struct ext4_new_group_input __user *)arg, sizeof(input))) return -EFAULT; + err = mnt_want_write(filp->f_path.mnt); + if (err) + return err; + err = ext4_group_add(sb, &input); jbd2_journal_lock_updates(EXT4_SB(sb)->s_journal); jbd2_journal_flush(EXT4_SB(sb)->s_journal); jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal); + mnt_drop_write(filp->f_path.mnt); return err; } -- cgit v1.2.3