From 328e24ae14aeb8ef624ec181e0d546b05c34f031 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 5 May 2020 17:43:15 +0200 Subject: ext4: fix fiemap size checks for bitmap files Add an extra validation of the len parameter, as for ext4 some files might have smaller file size limits than others. This also means the redundant size check in ext4_ioctl_get_es_cache can go away, as all size checking is done in the shared fiemap handler. Signed-off-by: Christoph Hellwig Reviewed-by: Ritesh Harjani Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20200505154324.3226743-3-hch@lst.de Signed-off-by: Theodore Ts'o --- fs/ext4/extents.c | 31 +++++++++++++++++++++++++++++++ 1 file changed, 31 insertions(+) (limited to 'fs/ext4/extents.c') diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index ce394706c61a..844773d3b64b 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -4862,6 +4862,28 @@ static const struct iomap_ops ext4_iomap_xattr_ops = { .iomap_begin = ext4_iomap_xattr_begin, }; +static int ext4_fiemap_check_ranges(struct inode *inode, u64 start, u64 *len) +{ + u64 maxbytes; + + if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) + maxbytes = inode->i_sb->s_maxbytes; + else + maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes; + + 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) + *len = maxbytes - start; + return 0; +} + static int _ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, __u64 start, __u64 len, bool from_es_cache) { @@ -4882,6 +4904,15 @@ static int _ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, if (fiemap_check_flags(fieinfo, ext4_fiemap_flags)) return -EBADR; + /* + * For bitmap files the maximum size limit could be smaller than + * s_maxbytes, so check len here manually instead of just relying on the + * generic check. + */ + error = ext4_fiemap_check_ranges(inode, start, &len); + if (error) + return error; + if (fieinfo->fi_flags & FIEMAP_FLAG_XATTR) { fieinfo->fi_flags &= ~FIEMAP_FLAG_XATTR; error = iomap_fiemap(inode, fieinfo, start, len, -- cgit v1.2.3