aesni: Fix yet another out-of-bounds read

[markj]

Summary

This is the same as 4285655adb74 ("aesni: Avoid a potential
out-of-bounds load in AES_GCM_encrypt()") except for the decryption
path. I failed to notice this last time since I assumed that encryption
and decryption use the same routine, like the CTR mode implementation
does.

Reported by: Jenkins (KASAN job)

[cem]

LGTM modulo overflow concern and what looks like a typo.

sys/crypto/aesni/aesni_ghash.c

793

Is this correct if nbytes was > 2GB? nbytes is a uint32 but resid is (signed) integer.

806

typo

[jhb]

sys/crypto/aesni/aesni_ghash.c

793

I think it still happens to work. Note that OCF itself can only describe buffers up to 2GB anyway (crp_payload_length is an int I think?)

[markj]

Drop the use of resid entirely, this is consistent with AES_GCM_encrypt() anyway.