sctp: auth: propagate HMAC calculation errors to callers

sctp_auth_calculate_hmac() can fail when building the association secret
under memory pressure, but its void return silently leaves the HMAC digest
zeroed.  On the receive path, sctp_sf_authenticate() compares this zeroed
digest against the peer-supplied one using crypto_memneq(), potentially
accepting an all-zero HMAC from the peer if the allocation failed.  On the
send path, sctp_packet_pack() transmits a packet with a zeroed HMAC that
the peer would reject.

Improve error handling by making sctp_auth_calculate_hmac() return int:
- sctp_sf_authenticate() returns SCTP_IERROR_NOMEM instead of accepting
  a zero HMAC.
- sctp_packet_pack() drops the packet on failure instead of transmitting
  a zeroed HMAC.

Update the declaration in auth.h accordingly.

Assisted-by: LLM
Signed-off-by: Qing Luo <luoqing@kylinos.cn>
Acked-by: Xin Long <lucien.xin@gmail.com>
Link: https://patch.msgid.link/20260807064314.500742-1-l1138897701@163.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

0 files changed, 0 insertions, 0 deletions