block: refine the EOF check in blkdev_iomap_begin

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: block: refine the EOF check in blkdev_iomap_begin blkdev_iomap_begin rounds down the offset to the logical block size before stashing it in iomap->offset and checking that it still is inside the inode size. Check the i_size check to the raw pos value so that we don't try a zero size write if iter->pos is unaligned.

References

• https://git.kernel.org/stable/c/910717920c8c3f9386277a44c44d448058a18084
• https://git.kernel.org/stable/c/72c54e063c32aeb38d43a2bd897821e6e5a1757d
• https://git.kernel.org/stable/c/10b723bcba8986537a484aa94dbfc9093fd776a1
• https://git.kernel.org/stable/c/0c12028aec837f5a002009bbf68d179d506510e8