1) " ext" length should be included into OPIE_CHALLENGE_MAX (as all places
of opie code expects that).
2) Overflow check in challenge.c is off by 1 even with corrected
OPIE_CHALLENGE_MAX
3) When fallback to randomchallenge() happens and rval is 0 (i.e.
challenge is too long), its value should be set to error state too.
To demonstrate the bug, run opiepasswd with valid seed:
opiepasswd -s 1234567890123456
and notice that it falls back to randomchallenge() (i.e. no
1234567890123456 in the prompt).
PR: 191511
Submitted by: mitsururike@gmail.com (partially)
MFC after: 1 week
41f23f3992