babeld: fix RFC violations in babel message parser #20339
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This commit fix various RFC violations found in `message.c`. 1. In Update message, this commit add a check to ignore the whole enclosing TLV if the mandatory bit of a sub-TLV is set. This commit also add a check to ensure that if AE is 3, Omitted must be zero. 2. In IHU message, this commit add similar mandatory bit check for sub-TLVs. 3. Add checks for `interval != 0` in various locations as RFC states that interval must not be zero. 4. Remove `Reserved == 0` checks from various locations, as RFC states that they must be ignored on recepton. 5. Add checks for `router_id` that ensure they must not be all zeros or all ones. 6. Add sub-TLV handling logic to various message types. Signed-off-by: spademomo <[email protected]>
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need to fix lint failures ... |
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Thank you for you review! I will fix the lint issue soon. |
| nh = neigh->address; | ||
| } | ||
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| // Add check that if AE (message[2]) is 3 (link-local IPv6), then Omitted (message[5]) must be 0 |
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Can we drop this (most likely for AI-assisted coding) comment?
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And is this related to rfc8966 previous (mandatory bit) handling?
| flog_err(EC_BABEL_PACKET, | ||
| "Received router id with all-ones value."); | ||
| goto fail; | ||
| } |
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The have_router_id flag is set to 1 before validation checks at lines 684-693. When validation fails (all-zero or all-ones router_id), the code exits via goto fail, but have_router_id remains 1 with an invalid router_id value. This causes subsequent MESSAGE_UPDATE messages in the same packet to incorrectly fail validation because they see have_router_id = 1 but router_id contains an invalid value, even though the original MESSAGE_ROUTER_ID TLV was rejected.
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This commit fix various RFC violations found in
message.c.interval != 0in various locations as RFC states that interval must not be zero.Reserved == 0checks from various locations, as RFC states that they must be ignored on recepton.router_idthat ensure they must not be all zeros or all ones.