The libnetfilter_conntrack userland library always sets IPS_CONFIRMED when building a CTA_STATUS attribute. If this toggles the bit from 0->1, the parser will return an error. On Linux 4.4+ this will cause any NFQA_EXP attribute in the packet to be ignored. This breaks conntrackd's userland helpers because they operate on unconfirmed connections. Instead of returning -EBUSY if the user program asks to modify an unchangeable bit, simply ignore the change. Also, fix the logic so that user programs are allowed to clear the bits that they are allowed to change.
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| @@ -82,6 +82,10 @@ enum ip_conntrack_status { · 81 unmodified lines | |||
| 82 | IPS_DYING_BIT = 9, | 82 | IPS_DYING_BIT = 9, |
| 83 | IPS_DYING = (1 << IPS_DYING_BIT), | 83 | IPS_DYING = (1 << IPS_DYING_BIT), |
| 84 | 84 | ||
| 85 | /* Bits that cannot be altered from userland. */ | ||
| 86 | IPS_UNCHANGEABLE_MASK = (IPS_NAT_DONE_MASK | IPS_NAT_MASK | | ||
| 87 | IPS_EXPECTED | IPS_CONFIRMED | IPS_DYING), | ||
| 88 | |||
| 85 | /* Connection has fixed timeout. */ | 89 | /* Connection has fixed timeout. */ |
| 86 | IPS_FIXED_TIMEOUT_BIT = 10, | 90 | IPS_FIXED_TIMEOUT_BIT = 10, |
| 87 | IPS_FIXED_TIMEOUT = (1 << IPS_FIXED_TIMEOUT_BIT), | 91 | IPS_FIXED_TIMEOUT = (1 << IPS_FIXED_TIMEOUT_BIT), |