fix(playbooks): correct off-by-one field count check in redfish.py ho…

[andrewwhitecdw]

…sts parsing

Summary

playbooks/files/redfish.py reads an Ansible-style hosts file and queries each host's BMC over the RedFish API to verify BIOS settings for confidential computing. If a host line in the hosts file is missing one or two trailing fields (e.g. no bmc_password=), the script crashes with an unhandled IndexError instead of printing the intended "Please update BMC IP, Username and Password details in hosts file" hint.

Root cause

bmc = item.strip().split(' ')
if len(bmc) > 6:
    host = bmc[6]
    user = bmc[7]
    pas = bmc[8]

The guard len(bmc) > 6 only guarantees index 6 exists, but the body also indexes bmc[7] and bmc[8]. A well-formed line has 9 fields (indices 0-8; the quoted ansible_ssh_common_args='-o ...' value splits into two tokens on the space). Lines with 7 or 8 fields pass the check and then crash:

| fields in line | len(bmc) | old check passes? | result | |---|---|---|---|
| 9 (well-formed) | 9 | yes | OK |
| 8 (missing password) | 8 | yes | IndexError at bmc[8] | | 7 (missing user+password) | 7 | yes | IndexError at bmc[7] | | <=6 | <=6 | no | prints usage hint |

Reproducer hosts file:

node1 ansible_ssh_user=nvidia ansible_ssh_pass=nvidia ansible_sudo_pass=nvidia bmc_ip=192.0.2.2 bmc_username=root

Traceback (most recent call last):
  File "redfish.py", line 19, in <module>
    user = bmc[7]
IndexError: list index out of range

Fix

One-character-class change: require all three indices to exist.

if len(bmc) > 8:

Testing

No automated tests exist in this repo for the playbooks or helper scripts (no CI configuration present), so the script was exercised manually with uv run --with requests python3 redfish.py hosts against a fixture hosts file containing:

1. a well-formed 9-field line (unreachable TEST-NET BMC IP),
2. a 7-field line (missing bmc_password= and one more field),
3. an 8-field line (missing bmc_password=).

• Unmodified script (from master): crashes with IndexError: list index out of range on line 19 for case 2 — bug reproduced.
• Fixed script: case 1 still attempts the RedFish connection (prints "Server is not for RedFish API" for the unreachable IP, as before), and cases 2 and 3 now print the intended "Please update BMC IP, Username and Password details in hosts file" hint; exit code 0.
• python3 -m py_compile playbooks/files/redfish.py passes.

Why existing tests missed it

The repository has no test suite or CI for this helper script; it is run manually against a site-specific hosts file, which in practice always contained well-formed lines.