pgsql: Fix not-terribly-safe coding in NIImportOOAffixes() and NIImport - Mailing list pgsql-committers

From Tom Lane
Subject pgsql: Fix not-terribly-safe coding in NIImportOOAffixes() and NIImport
Date
Msg-id E1acivO-0005er-Jy@gemulon.postgresql.org
Whole thread Raw
List pgsql-committers
Fix not-terribly-safe coding in NIImportOOAffixes() and NIImportAffixes().

There were two places in spell.c that supposed that they could search
for a location in a string produced by lowerstr() and then transpose
the offset into the original string.  But this fails completely if
lowerstr() transforms any characters into characters of different byte
length, as can happen in Turkish UTF8 for instance.

We'd added some comments about this coding in commit 51e78ab4ff328296,
but failed to realize that it was not merely confusing but wrong.

Coverity complained about this code years ago, but in such an opaque
fashion that nobody understood what it was on about.  I'm not entirely
sure that this issue *is* what it's on about, actually, but perhaps
this patch will shut it up -- and in any case the problem is clear.

Back-patch to all supported branches.

Branch
------
REL9_4_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/3fa4715c506128405631e84bc91efb90e95b0ca7

Modified Files
--------------
src/backend/tsearch/spell.c | 35 ++++++++++++++++++++++-------------
1 file changed, 22 insertions(+), 13 deletions(-)


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