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mirror of https://github.com/postgres/postgres.git synced 2026-10-23 13:29:09 +03:00

Fix ILIKE patterns with non-ASCII bytes in single-byte encodings.

Commit 1e493158d3 changed the MATCH_LOWER implementation of GETCHAR()
from SB_lower_char() to use pg_ascii_tolower().  The latter returns an
unsigned char; but the local variable in C_IMatchText was a char.

For single-byte encodings and the C locale, that could lead to a
broken signed/unsigned comparison.  For example, the pattern
U&'%\00C6' would never match.

Fix by casting the result of pg_ascii_tolower() explicitly to char.

Reported-by: Greg Burd <greg@burd.me>
Reviewed-by: Greg Burd <greg@burd.me>
Discussion: https://postgr.es/m/_GW2V-rd0QW4BTguAJriA9XVmjOn2mR3-YeAZr9ZU6EtlLvYPEm_r_fV5wGKzSNMzboj_nqn3fk72AYAvOKzEnPlCCHteaYrgESrIhPg6l8=@burd.me
Backpatch-through: 19
This commit is contained in:
Jeff Davis
2026-10-21 05:46:37 -07:00
parent 6b9f40d49a
commit c00a97b646

View File

@@ -75,7 +75,8 @@
* locales must casefold the inputs before matching.
*/
#ifdef MATCH_LOWER
#define GETCHAR(t) pg_ascii_tolower(t)
/* cast to char to match data types in caller */
#define GETCHAR(t) ((char) pg_ascii_tolower(t))
#else
#define GETCHAR(t) (t)
#endif