In the Linux kernel, the following vulnerability has been resolved:
xfs: don't walk off the end of a directory data block
This adds sanity checks for xfsdir2dataunused and xfsdir2dataentry to make sure don't stray beyond valid memory region. Before patching, the loop simply checks that the start offset of the dup and dep is within the range. So in a crafted image, if last entry is xfsdir2data_unused, we can change dup->length to dup->length-1 and leave 1 byte of space. In the next traversal, this space will be considered as dup or dep. We may encounter an out of bound read when accessing the fixed members.
In the patch, we make sure that the remaining bytes large enough to hold an unused entry before accessing xfsdir2dataunused and xfsdir2dataunused is XFSDIR2DATAALIGN byte aligned. We also make sure that the remaining bytes large enough to hold a dirent with a single-byte name before accessing xfsdir2dataentry.