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Commit 4dfb761c authored by Eric Biggers's avatar Eric Biggers
Browse files

ANDROID: fscrypt: set dun_bytes more precisely 



Make fscrypt set dun_bytes to only what it actually needs, so that it
can make use of inline crypto hardware in more cases.

Bug: 144046242
Bug: 153512828
Change-Id: I36f90ea6b64ef51a9d58ffb069d2cba74965c239
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
parent e74407ee

fs/crypto/inline_crypt.c

+12 −5
Original line number Diff line number Diff line
@@ -43,13 +43,20 @@ static void fscrypt_get_devices(struct super_block *sb, int num_devs, 


static unsigned int fscrypt_get_dun_bytes(const struct fscrypt_info *ci)

{

	unsigned int dun_bytes = 8;

	struct super_block *sb = ci->ci_inode->i_sb;

	unsigned int flags = fscrypt_policy_flags(&ci->ci_policy);

	int ino_bits = 64, lblk_bits = 64;



	if (fscrypt_policy_flags(&ci->ci_policy) &

	    FSCRYPT_POLICY_FLAG_DIRECT_KEY)

		dun_bytes += FS_KEY_DERIVATION_NONCE_SIZE;

	if (flags & FSCRYPT_POLICY_FLAG_DIRECT_KEY)

		return offsetofend(union fscrypt_iv, nonce);



	return dun_bytes;

	if (flags & FSCRYPT_POLICY_FLAG_IV_INO_LBLK_64)

		return sizeof(__le64);



	/* Default case: IVs are just the file logical block number */

	if (sb->s_cop->get_ino_and_lblk_bits)

		sb->s_cop->get_ino_and_lblk_bits(sb, &ino_bits, &lblk_bits);

	return DIV_ROUND_UP(lblk_bits, 8);

}



/* Enable inline encryption for this file if supported. */