From cddf8a2c4a8286ae60fc866eab59c8bc524e93a0 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sat, 23 May 2020 09:30:13 +0200 Subject: fs: move fiemap range validation into the file systems instances Replace fiemap_check_flags with a fiemap_prep helper that also takes the inode and mapped range, and performs the sanity check and truncation previously done in fiemap_check_range. This way the validation is inside the file system itself and thus properly works for the stacked overlayfs case as well. Signed-off-by: Christoph Hellwig Reviewed-by: Amir Goldstein Reviewed-by: Darrick J. Wong Link: https://lore.kernel.org/r/20200523073016.2944131-7-hch@lst.de Signed-off-by: Theodore Ts'o --- fs/ioctl.c | 63 ++++++++++++++++++++++++-------------------------------------- 1 file changed, 24 insertions(+), 39 deletions(-) (limited to 'fs/ioctl.c') diff --git a/fs/ioctl.c b/fs/ioctl.c index 3f300cc07dee..56bbf02209ae 100644 --- a/fs/ioctl.c +++ b/fs/ioctl.c @@ -149,61 +149,50 @@ int fiemap_fill_next_extent(struct fiemap_extent_info *fieinfo, u64 logical, EXPORT_SYMBOL(fiemap_fill_next_extent); /** - * fiemap_check_flags - check validity of requested flags for fiemap + * fiemap_prep - check validity of requested flags for fiemap + * @inode: Inode to operate on * @fieinfo: Fiemap context passed into ->fiemap - * @fs_flags: Set of fiemap flags that the file system understands + * @start: Start of the mapped range + * @len: Length of the mapped range, can be truncated by this function. + * @supported_flags: Set of fiemap flags that the file system understands * - * Called from file system ->fiemap callback. This will compute the - * intersection of valid fiemap flags and those that the fs supports. That - * value is then compared against the user supplied flags. In case of bad user - * flags, the invalid values will be written into the fieinfo structure, and - * -EBADR is returned, which tells ioctl_fiemap() to return those values to - * userspace. For this reason, a return code of -EBADR should be preserved. + * This function must be called from each ->fiemap instance to validate the + * fiemap request against the file system parameters. * - * Returns 0 on success, -EBADR on bad flags. + * Returns 0 on success, or a negative error on failure. */ -int fiemap_check_flags(struct fiemap_extent_info *fieinfo, u32 fs_flags) +int fiemap_prep(struct inode *inode, struct fiemap_extent_info *fieinfo, + u64 start, u64 *len, u32 supported_flags) { + u64 maxbytes = inode->i_sb->s_maxbytes; u32 incompat_flags; - incompat_flags = fieinfo->fi_flags & ~(FIEMAP_FLAGS_COMPAT & fs_flags); - if (incompat_flags) { - fieinfo->fi_flags = incompat_flags; - return -EBADR; - } - return 0; -} -EXPORT_SYMBOL(fiemap_check_flags); - -static int fiemap_check_ranges(struct super_block *sb, - u64 start, u64 len, u64 *new_len) -{ - u64 maxbytes = (u64) sb->s_maxbytes; - - *new_len = len; - - if (len == 0) + if (*len == 0) return -EINVAL; - if (start > maxbytes) return -EFBIG; /* * Shrink request scope to what the fs can actually handle. */ - if (len > maxbytes || (maxbytes - len) < start) - *new_len = maxbytes - start; + if (*len > maxbytes || (maxbytes - *len) < start) + *len = maxbytes - start; + supported_flags &= FIEMAP_FLAGS_COMPAT; + incompat_flags = fieinfo->fi_flags & ~supported_flags; + if (incompat_flags) { + fieinfo->fi_flags = incompat_flags; + return -EBADR; + } return 0; } +EXPORT_SYMBOL(fiemap_prep); static int ioctl_fiemap(struct file *filp, struct fiemap __user *ufiemap) { struct fiemap fiemap; struct fiemap_extent_info fieinfo = { 0, }; struct inode *inode = file_inode(filp); - struct super_block *sb = inode->i_sb; - u64 len; int error; if (!inode->i_op->fiemap) @@ -215,11 +204,6 @@ static int ioctl_fiemap(struct file *filp, struct fiemap __user *ufiemap) if (fiemap.fm_extent_count > FIEMAP_MAX_EXTENTS) return -EINVAL; - error = fiemap_check_ranges(sb, fiemap.fm_start, fiemap.fm_length, - &len); - if (error) - return error; - fieinfo.fi_flags = fiemap.fm_flags; fieinfo.fi_extents_max = fiemap.fm_extent_count; fieinfo.fi_extents_start = ufiemap->fm_extents; @@ -232,7 +216,8 @@ static int ioctl_fiemap(struct file *filp, struct fiemap __user *ufiemap) if (fieinfo.fi_flags & FIEMAP_FLAG_SYNC) filemap_write_and_wait(inode->i_mapping); - error = inode->i_op->fiemap(inode, &fieinfo, fiemap.fm_start, len); + error = inode->i_op->fiemap(inode, &fieinfo, fiemap.fm_start, + fiemap.fm_length); fiemap.fm_flags = fieinfo.fi_flags; fiemap.fm_mapped_extents = fieinfo.fi_extents_mapped; if (copy_to_user(ufiemap, &fiemap, sizeof(fiemap))) @@ -320,7 +305,7 @@ static int __generic_block_fiemap(struct inode *inode, bool past_eof = false, whole_file = false; int ret = 0; - ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC); + ret = fiemap_prep(inode, fieinfo, start, &len, FIEMAP_FLAG_SYNC); if (ret) return ret; -- cgit