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Eric Biggers
80f6e3080b
If the file size is almost S64_MAX, the calculated number of Merkle tree levels exceeds FS_VERITY_MAX_LEVELS, causing FS_IOC_ENABLE_VERITY to fail. This is unintentional, since as the comment above the definition of FS_VERITY_MAX_LEVELS states, it is enough for over U64_MAX bytes of data using SHA-256 and 4K blocks. (Specifically, 4096*128**8 >= 2**64.) The bug is actually that when the number of blocks in the first level is calculated from i_size, there is a signed integer overflow due to i_size being signed. Fix this by treating i_size as unsigned. This was found by the new test "generic: test fs-verity EFBIG scenarios" (https://lkml.kernel.org/r/b1d116cd4d0ea74b9cd86f349c672021e005a75c.1631558495.git.boris@bur.io). This didn't affect ext4 or f2fs since those have a smaller maximum file size, but it did affect btrfs which allows files up to S64_MAX bytes. Reported-by: Boris Burkov <[email protected]> Fixes:3fda4c617e("fs-verity: implement FS_IOC_ENABLE_VERITY ioctl") Fixes:fd2d1acfca("fs-verity: add the hook for file ->open()") Cc: <[email protected]> # v5.4+ Reviewed-by: Boris Burkov <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Eric Biggers <[email protected]>