CVE-2023-2911

If the recursive-clients quota is reached on a BIND 9 resolver configured with both stale-answer-enable yes; and stale-answer-client-timeout 0;, a sequence of serve-stale-related lookups could cause named to loop and terminate unexpectedly due to a stack overflow. This issue affects BIND 9 versions 9.16.33 through 9.16.41, 9.18.7 through 9.18.15, 9.16.33-S1 through 9.16.41-S1, and 9.18.11-S1 through 9.18.15-S1.

If the recursive-clients quota is reached on a BIND 9 resolver configured with both stale-answer-enable yes; and stale-answer-client-timeout 0;, a sequence of serve-stale-related lookups could cause named to loop and terminate unexpectedly due to a stack overflow. This issue affects BIND 9 versions 9.16.33 through 9.16.41, 9.18.7 through 9.18.15, 9.16.33-S1 through 9.16.41-S1, and 9.18.11-S1 through 9.18.15-S1.

If the recursive-clients quota is reached on a BIND 9 resolver configured with both stale-answer-enable yes; and stale-answer-client-timeout 0;, a sequence of serve-stale-related lookups could cause named to loop and terminate unexpectedly due to a stack overflow. This issue affects BIND 9 versions 9.16.33 through 9.16.41, 9.18.7 through 9.18.15, 9.16.33-S1 through 9.16.41-S1, and 9.18.11-S1 through 9.18.15-S1.

These are all security issues fixed in the bind-9.18.16-1.1 package on the GA media of openSUSE Tumbleweed.

This update for bind fixes the following issues:

Update to release 9.16.42

Security Fixes:

• The overmem cleaning process has been improved, to prevent the cache from significantly exceeding the configured max-cache-size limit. (CVE-2023-2828)
• A query that prioritizes stale data over lookup triggers a fetch to refresh the stale data in cache. If the fetch is aborted for exceeding the recursion quota, it was possible for named to enter an infinite callback loop and crash due to stack overflow. This has been fixed. (CVE-2023-2911)

Bug Fixes:

• Previously, it was possible for a delegation from cache to be returned to the client after the stale-answer-client-timeout duration. This has been fixed. [bsc#1212544, bsc#1212567, jsc#SLE-24600]

Update to release 9.16.41

Bug Fixes:

• When removing delegations from an opt-out range, empty-non-terminal NSEC3 records generated by those delegations were not cleaned up. This has been fixed. [jsc#SLE-24600]

Update to release 9.16.40

Bug Fixes:

• Logfiles using timestamp-style suffixes were not always correctly removed when the number of files exceeded the limit set by versions. This has been fixed for configurations which do not explicitly specify a directory path as part of the file argument in the channel specification.
• Performance of DNSSEC validation in zones with many DNSKEY records has been improved.

Update to release 9.16.39

Feature Changes:

• libuv support for receiving multiple UDP messages in a single recvmmsg() system call has been tweaked several times between libuv versions 1.35.0 and 1.40.0; the current recommended libuv version is 1.40.0 or higher. New rules are now in effect for running with a different version of libuv than the one used at compilation time. These rules may trigger a fatal error at startup:

  • Building against or running with libuv versions 1.35.0 and 1.36.0 is now a fatal error.
  • Running with libuv version higher than 1.34.2 is now a fatal error when named is built against libuv version 1.34.2 or lower.
  • Running with libuv version higher than 1.39.0 is now a fatal error when named is built against libuv version 1.37.0, 1.38.0, 1.38.1, or 1.39.0.

• This prevents the use of libuv versions that may trigger an assertion failure when receiving multiple UDP messages in a single system call.

Bug Fixes:

• named could crash with an assertion failure when adding a new zone into the configuration file for a name which was already configured as a member zone for a catalog zone. This has been fixed.
• When named starts up, it sends a query for the DNSSEC key for each configured trust anchor to determine whether the key has changed. In some unusual cases, the query might depend on a zone for which the server is itself authoritative, and would have failed if it were sent before the zone was fully loaded. This has now been fixed by delaying the key queries until all zones have finished loading. [jsc#SLE-24600]

This update for bind fixes the following issues:

Update to release 9.16.42

Security Fixes:

• The overmem cleaning process has been improved, to prevent the cache from significantly exceeding the configured max-cache-size limit. (CVE-2023-2828)
• A query that prioritizes stale data over lookup triggers a fetch to refresh the stale data in cache. If the fetch is aborted for exceeding the recursion quota, it was possible for named to enter an infinite callback loop and crash due to stack overflow. This has been fixed. (CVE-2023-2911)

Bug Fixes:

• Previously, it was possible for a delegation from cache to be returned to the client after the stale-answer-client-timeout duration. This has been fixed. [bsc#1212544, bsc#1212567, jsc#SLE-24600]

Update to release 9.16.41

Bug Fixes:

• When removing delegations from an opt-out range, empty-non-terminal NSEC3 records generated by those delegations were not cleaned up. This has been fixed. [jsc#SLE-24600]

Update to release 9.16.40

Bug Fixes:

• Logfiles using timestamp-style suffixes were not always correctly removed when the number of files exceeded the limit set by versions. This has been fixed for configurations which do not explicitly specify a directory path as part of the file argument in the channel specification.
• Performance of DNSSEC validation in zones with many DNSKEY records has been improved.

Update to release 9.16.39

Feature Changes:

• libuv support for receiving multiple UDP messages in a single recvmmsg() system call has been tweaked several times between libuv versions 1.35.0 and 1.40.0; the current recommended libuv version is 1.40.0 or higher. New rules are now in effect for running with a different version of libuv than the one used at compilation time. These rules may trigger a fatal error at startup:

  • Building against or running with libuv versions 1.35.0 and 1.36.0 is now a fatal error.
  • Running with libuv version higher than 1.34.2 is now a fatal error when named is built against libuv version 1.34.2 or lower.
  • Running with libuv version higher than 1.39.0 is now a fatal error when named is built against libuv version 1.37.0, 1.38.0, 1.38.1, or 1.39.0.

• This prevents the use of libuv versions that may trigger an assertion failure when receiving multiple UDP messages in a single system call.

Bug Fixes:

• named could crash with an assertion failure when adding a new zone into the configuration file for a name which was already configured as a member zone for a catalog zone. This has been fixed.
• When named starts up, it sends a query for the DNSSEC key for each configured trust anchor to determine whether the key has changed. In some unusual cases, the query might depend on a zone for which the server is itself authoritative, and would have failed if it were sent before the zone was fully loaded. This has now been fixed by delaying the key queries until all zones have finished loading. [jsc#SLE-24600]

Shoham Danino, Anat Bremler-Barr, Yehuda Afek, and Yuval Shavitt discovered that Bind incorrectly handled the cache size limit. A remote attacker could possibly use this issue to consume memory, leading to a denial of service. (CVE-2023-2828)

It was discovered that Bind incorrectly handled the recursive-clients quota. A remote attacker could possibly use this issue to cause Bind to crash, resulting in a denial of service. This issue only affected Ubuntu 22.04 LTS, Ubuntu 22.10, and Ubuntu 23.04. (CVE-2023-2911)