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pgsql: Avoid overflow in Levenshtein distance calculations. 5+ messages / 1 participants [nested] [flat]
* pgsql: Avoid overflow in Levenshtein distance calculations. @ 2026-08-10 13:41 Noah Misch <noah@leadboat.com> 0 siblings, 0 replies; 5+ messages in thread From: Noah Misch @ 2026-08-10 13:41 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Avoid overflow in Levenshtein distance calculations. levenshtein() and levenshtein_less_equal() let the caller specify the insertion, deletion, and substitution costs, and fuzzystrmatch's corresponding SQL functions accept any 32-bit integer for each. Since the distances are calculated with 32-bit arithmetic, large costs can cause overflows, thereby producing nonsensical results. Certain inputs to levenshtein_less_equal() can even cause out-of-bounds writes. To fix, use 64-bit arithmetic instead, and error whenever the final result won't fit in the returned 32-bit integer. We may want to teach these functions to reject negative costs, too, but that didn't seem appropriate for a security fix, and therefore it is left as a future exercise. Reported-by: Ben Morris in collaboration with Claude and Anthropic Research Author: Nathan Bossart <nathandbossart@gmail.com> Reviewed-by: Dean Rasheed <dean.a.rasheed@gmail.com> Security: CVE-2026-15742 Backpatch-through: 14 Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/918683d12d849a514cd38056aab882322c74adb4 Author: Nathan Bossart <nathan@postgresql.org> Modified Files -------------- contrib/fuzzystrmatch/expected/fuzzystrmatch.out | 14 ++++ contrib/fuzzystrmatch/sql/fuzzystrmatch.sql | 3 + src/backend/utils/adt/levenshtein.c | 89 ++++++++++++------------ src/backend/utils/adt/varlena.c | 14 ++++ 4 files changed, 77 insertions(+), 43 deletions(-) ^ permalink raw reply [nested|flat] 5+ messages in thread
* pgsql: Avoid overflow in Levenshtein distance calculations. @ 2026-08-10 13:41 Noah Misch <noah@leadboat.com> 0 siblings, 0 replies; 5+ messages in thread From: Noah Misch @ 2026-08-10 13:41 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Avoid overflow in Levenshtein distance calculations. levenshtein() and levenshtein_less_equal() let the caller specify the insertion, deletion, and substitution costs, and fuzzystrmatch's corresponding SQL functions accept any 32-bit integer for each. Since the distances are calculated with 32-bit arithmetic, large costs can cause overflows, thereby producing nonsensical results. Certain inputs to levenshtein_less_equal() can even cause out-of-bounds writes. To fix, use 64-bit arithmetic instead, and error whenever the final result won't fit in the returned 32-bit integer. We may want to teach these functions to reject negative costs, too, but that didn't seem appropriate for a security fix, and therefore it is left as a future exercise. Reported-by: Ben Morris in collaboration with Claude and Anthropic Research Author: Nathan Bossart <nathandbossart@gmail.com> Reviewed-by: Dean Rasheed <dean.a.rasheed@gmail.com> Security: CVE-2026-15742 Backpatch-through: 14 Branch ------ REL_19_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/62c31b490d94b38a62869593524abca5f67c4c46 Author: Nathan Bossart <nathan@postgresql.org> Modified Files -------------- contrib/fuzzystrmatch/expected/fuzzystrmatch.out | 14 ++++ contrib/fuzzystrmatch/sql/fuzzystrmatch.sql | 3 + src/backend/utils/adt/levenshtein.c | 89 ++++++++++++------------ src/backend/utils/adt/varlena.c | 14 ++++ 4 files changed, 77 insertions(+), 43 deletions(-) ^ permalink raw reply [nested|flat] 5+ messages in thread
* pgsql: Avoid overflow in Levenshtein distance calculations. @ 2026-08-10 13:41 Noah Misch <noah@leadboat.com> 0 siblings, 0 replies; 5+ messages in thread From: Noah Misch @ 2026-08-10 13:41 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Avoid overflow in Levenshtein distance calculations. levenshtein() and levenshtein_less_equal() let the caller specify the insertion, deletion, and substitution costs, and fuzzystrmatch's corresponding SQL functions accept any 32-bit integer for each. Since the distances are calculated with 32-bit arithmetic, large costs can cause overflows, thereby producing nonsensical results. Certain inputs to levenshtein_less_equal() can even cause out-of-bounds writes. To fix, use 64-bit arithmetic instead, and error whenever the final result won't fit in the returned 32-bit integer. We may want to teach these functions to reject negative costs, too, but that didn't seem appropriate for a security fix, and therefore it is left as a future exercise. Reported-by: Ben Morris in collaboration with Claude and Anthropic Research Author: Nathan Bossart <nathandbossart@gmail.com> Reviewed-by: Dean Rasheed <dean.a.rasheed@gmail.com> Security: CVE-2026-15742 Backpatch-through: 14 Branch ------ REL_18_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/e88eb4e766381070f42e5b84e583a1d0288983f7 Author: Nathan Bossart <nathan@postgresql.org> Modified Files -------------- contrib/fuzzystrmatch/expected/fuzzystrmatch.out | 14 ++++ contrib/fuzzystrmatch/sql/fuzzystrmatch.sql | 3 + src/backend/utils/adt/levenshtein.c | 89 ++++++++++++------------ src/backend/utils/adt/varlena.c | 14 ++++ 4 files changed, 77 insertions(+), 43 deletions(-) ^ permalink raw reply [nested|flat] 5+ messages in thread
* pgsql: Avoid overflow in Levenshtein distance calculations. @ 2026-08-10 13:41 Noah Misch <noah@leadboat.com> 0 siblings, 0 replies; 5+ messages in thread From: Noah Misch @ 2026-08-10 13:41 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Avoid overflow in Levenshtein distance calculations. levenshtein() and levenshtein_less_equal() let the caller specify the insertion, deletion, and substitution costs, and fuzzystrmatch's corresponding SQL functions accept any 32-bit integer for each. Since the distances are calculated with 32-bit arithmetic, large costs can cause overflows, thereby producing nonsensical results. Certain inputs to levenshtein_less_equal() can even cause out-of-bounds writes. To fix, use 64-bit arithmetic instead, and error whenever the final result won't fit in the returned 32-bit integer. We may want to teach these functions to reject negative costs, too, but that didn't seem appropriate for a security fix, and therefore it is left as a future exercise. Reported-by: Ben Morris in collaboration with Claude and Anthropic Research Author: Nathan Bossart <nathandbossart@gmail.com> Reviewed-by: Dean Rasheed <dean.a.rasheed@gmail.com> Security: CVE-2026-15742 Backpatch-through: 14 Branch ------ REL_17_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/c4d51b62748fd697e5ef4c1108dc77396ba39475 Author: Nathan Bossart <nathan@postgresql.org> Modified Files -------------- contrib/fuzzystrmatch/expected/fuzzystrmatch.out | 14 ++++ contrib/fuzzystrmatch/sql/fuzzystrmatch.sql | 3 + src/backend/utils/adt/levenshtein.c | 89 ++++++++++++------------ src/backend/utils/adt/varlena.c | 14 ++++ 4 files changed, 77 insertions(+), 43 deletions(-) ^ permalink raw reply [nested|flat] 5+ messages in thread
* pgsql: Avoid overflow in Levenshtein distance calculations. @ 2026-08-10 13:41 Noah Misch <noah@leadboat.com> 0 siblings, 0 replies; 5+ messages in thread From: Noah Misch @ 2026-08-10 13:41 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org Avoid overflow in Levenshtein distance calculations. levenshtein() and levenshtein_less_equal() let the caller specify the insertion, deletion, and substitution costs, and fuzzystrmatch's corresponding SQL functions accept any 32-bit integer for each. Since the distances are calculated with 32-bit arithmetic, large costs can cause overflows, thereby producing nonsensical results. Certain inputs to levenshtein_less_equal() can even cause out-of-bounds writes. To fix, use 64-bit arithmetic instead, and error whenever the final result won't fit in the returned 32-bit integer. We may want to teach these functions to reject negative costs, too, but that didn't seem appropriate for a security fix, and therefore it is left as a future exercise. Reported-by: Ben Morris in collaboration with Claude and Anthropic Research Author: Nathan Bossart <nathandbossart@gmail.com> Reviewed-by: Dean Rasheed <dean.a.rasheed@gmail.com> Security: CVE-2026-15742 Backpatch-through: 14 Branch ------ REL_16_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/61481aa0e4aa66c32a8826732f30d17d4c488d06 Author: Nathan Bossart <nathan@postgresql.org> Modified Files -------------- contrib/fuzzystrmatch/expected/fuzzystrmatch.out | 14 ++++ contrib/fuzzystrmatch/sql/fuzzystrmatch.sql | 3 + src/backend/utils/adt/levenshtein.c | 89 ++++++++++++------------ src/backend/utils/adt/varlena.c | 14 ++++ 4 files changed, 77 insertions(+), 43 deletions(-) ^ permalink raw reply [nested|flat] 5+ messages in thread
end of thread, other threads:[~2026-08-10 13:41 UTC | newest] Thread overview: 5+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2026-08-10 13:41 pgsql: Avoid overflow in Levenshtein distance calculations. Noah Misch <noah@leadboat.com> 2026-08-10 13:41 pgsql: Avoid overflow in Levenshtein distance calculations. Noah Misch <noah@leadboat.com> 2026-08-10 13:41 pgsql: Avoid overflow in Levenshtein distance calculations. Noah Misch <noah@leadboat.com> 2026-08-10 13:41 pgsql: Avoid overflow in Levenshtein distance calculations. Noah Misch <noah@leadboat.com> 2026-08-10 13:41 pgsql: Avoid overflow in Levenshtein distance calculations. Noah Misch <noah@leadboat.com>
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