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/ext3/ioctl.c | 103 +++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 68 insertions(+), 35 deletions(-) (limited to 'fs/ext3/ioctl.c') diff --git a/fs/ext3/ioctl.c b/fs/ext3/ioctl.c index 023a070f55f1..0d0c70151642 100644 --- a/fs/ext3/ioctl.c +++ b/fs/ext3/ioctl.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -38,14 +39,19 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd, unsigned int oldflags; unsigned int jflag; - if (IS_RDONLY(inode)) - return -EROFS; + err = mnt_want_write(filp->f_path.mnt); + if (err) + return err; - if (!is_owner_or_cap(inode)) - return -EACCES; + if (!is_owner_or_cap(inode)) { + err = -EACCES; + goto flags_out; + } - if (get_user(flags, (int __user *) arg)) - return -EFAULT; + if (get_user(flags, (int __user *) arg)) { + err = -EFAULT; + goto flags_out; + } if (!S_ISDIR(inode->i_mode)) flags &= ~EXT3_DIRSYNC_FL; @@ -54,7 +60,8 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd, /* Is it quota file? Do not allow user to mess with it */ if (IS_NOQUOTA(inode)) { mutex_unlock(&inode->i_mutex); - return -EPERM; + err = -EPERM; + goto flags_out; } oldflags = ei->i_flags; @@ -70,7 +77,8 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd, if ((flags ^ oldflags) & (EXT3_APPEND_FL | EXT3_IMMUTABLE_FL)) { if (!capable(CAP_LINUX_IMMUTABLE)) { mutex_unlock(&inode->i_mutex); - return -EPERM; + err = -EPERM; + goto flags_out; } } @@ -81,7 +89,8 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd, if ((jflag ^ oldflags) & (EXT3_JOURNAL_DATA_FL)) { if (!capable(CAP_SYS_RESOURCE)) { mutex_unlock(&inode->i_mutex); - return -EPERM; + err = -EPERM; + goto flags_out; } } @@ -89,7 +98,8 @@ int ext3_ioctl (struct inode * inode, struct file * filp, unsigned int cmd, handle = ext3_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; @@ -115,6 +125,8 @@ flags_err: if ((jflag ^ oldflags) & (EXT3_JOURNAL_DATA_FL)) err = ext3_change_inode_journal_flag(inode, jflag); mutex_unlock(&inode->i_mutex); +flags_out: + mnt_drop_write(filp->f_path.mnt); return err; } case EXT3_IOC_GETVERSION: @@ -129,14 +141,18 @@ 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 = ext3_journal_start(inode, 1); - if (IS_ERR(handle)) - return PTR_ERR(handle); + if (IS_ERR(handle)) { + err = PTR_ERR(handle); + goto setversion_out; + } err = ext3_reserve_inode_write(handle, inode, &iloc); if (err == 0) { inode->i_ctime = CURRENT_TIME_SEC; @@ -144,6 +160,8 @@ flags_err: err = ext3_mark_iloc_dirty(handle, inode, &iloc); } ext3_journal_stop(handle); +setversion_out: + mnt_drop_write(filp->f_path.mnt); return err; } #ifdef CONFIG_JBD_DEBUG @@ -179,18 +197,24 @@ flags_err: } return -ENOTTY; case EXT3_IOC_SETRSVSZ: { + int err; if (!test_opt(inode->i_sb, RESERVATION) ||!S_ISREG(inode->i_mode)) return -ENOTTY; - if (IS_RDONLY(inode)) - return -EROFS; + err = mnt_want_write(filp->f_path.mnt); + if (err) + return err; - if (!is_owner_or_cap(inode)) - return -EACCES; + if (!is_owner_or_cap(inode)) { + err = -EACCES; + goto setrsvsz_out; + } - if (get_user(rsv_window_size, (int __user *)arg)) - return -EFAULT; + if (get_user(rsv_window_size, (int __user *)arg)) { + err = -EFAULT; + goto setrsvsz_out; + } if (rsv_window_size > EXT3_MAX_RESERVE_BLOCKS) rsv_window_size = EXT3_MAX_RESERVE_BLOCKS; @@ -208,7 +232,9 @@ flags_err: rsv->rsv_goal_size = rsv_window_size; } mutex_unlock(&ei->truncate_mutex); - return 0; +setrsvsz_out: + mnt_drop_write(filp->f_path.mnt); + return err; } case EXT3_IOC_GROUP_EXTEND: { ext3_fsblk_t n_blocks_count; @@ -218,17 +244,20 @@ 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; + if (get_user(n_blocks_count, (__u32 __user *)arg)) { + err = -EFAULT; + goto group_extend_out; + } err = ext3_group_extend(sb, EXT3_SB(sb)->s_es, n_blocks_count); journal_lock_updates(EXT3_SB(sb)->s_journal); journal_flush(EXT3_SB(sb)->s_journal); journal_unlock_updates(EXT3_SB(sb)->s_journal); - +group_extend_out: + mnt_drop_write(filp->f_path.mnt); return err; } case EXT3_IOC_GROUP_ADD: { @@ -239,18 +268,22 @@ flags_err: if (!capable(CAP_SYS_RESOURCE)) return -EPERM; - if (IS_RDONLY(inode)) - return -EROFS; + err = mnt_want_write(filp->f_path.mnt); + if (err) + return err; if (copy_from_user(&input, (struct ext3_new_group_input __user *)arg, - sizeof(input))) - return -EFAULT; + sizeof(input))) { + err = -EFAULT; + goto group_add_out; + } err = ext3_group_add(sb, &input); journal_lock_updates(EXT3_SB(sb)->s_journal); journal_flush(EXT3_SB(sb)->s_journal); journal_unlock_updates(EXT3_SB(sb)->s_journal); - +group_add_out: + mnt_drop_write(filp->f_path.mnt); return err; } -- cgit v1.2.3