Re: [PATCH] ecryptfs: Use MD5 library instead of crypto_shash

Christian Brauner
2025-10-21T12:59:57Z

On Sat, 11 Oct 2025 13:00:10 -0700, Eric Biggers wrote:
> eCryptfs uses MD5 for a couple unusual purposes: to "mix" the key into
> the IVs for file contents encryption (similar to ESSIV), and to prepend
> some key-dependent bytes to the plaintext when encrypting filenames
> (which is useless since eCryptfs encrypts the filenames with ECB).
>
> Currently, eCryptfs computes these MD5 hashes using the crypto_shash
> API. Update it to instead use the MD5 library API. This is simpler and
> faster: the library doesn't require memory allocations, can't fail, and
> provides direct access to MD5 without overhead such as indirect calls.
>
> [...]

Applied to the vfs-6.19.misc branch of the vfs/vfs.git tree.
Patches in the vfs-6.19.misc branch should appear in linux-next soon.

Please report any outstanding bugs that were missed during review in a
new review to the original patch series allowing us to drop it.

It's encouraged to provide Acked-bys and Reviewed-bys even though the
patch has now been applied. If possible patch trailers will be updated.

Note that commit hashes shown below are subject to change due to rebase,
trailer updates or similar. If in doubt, please check the listed branch.

tree: https://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs.git
branch: vfs-6.19.misc

[1/1] ecryptfs: Use MD5 library instead of crypto_shash