CVSROOT: /cvs
Module name: src
Changes by: js...@cvs.openbsd.org 2022/02/01 10:13:10
Modified files:
lib/libtls : tls.h tls_signer.c
Log message:
Revise signer callback interface.
The current design of tls_sign_cb provides a pointer to a buffer where the
signature needs to be copied, however it fails to provide a length which
could result in buffer overwrites. Furthermore, tls_signer_sign() is
designed such that it allocates and returns ownership to the caller.
Revise tls_sign_cb so that the called function is expected to allocate a
buffer, returning ownership of the buffer (along with its length) to the
caller of the callback. This makes it far easier (and safer) to implement
a tls_sign_cb callback, plus tls_signer_sign can be directly plugged in
(with an appropriate cast).
While here, rename and reorder some arguments - while we will normally
sign a digest, there is no requirement for this to be the case hence use
'input' and 'input_len'. Move padding (an input) before the outputs and
add some additional bounds/return value checks.
This is technically an API/ABI break that would need a libtls major bump,
however since nothing is using the signer interface (outside of regress),
we'll ride the original minor bump.
With input from tb@
ok inoguchi@ tb@
