From 54fd196ffc6432b62fe075e564f457db64fb288c Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sun, 15 Jul 2012 13:27:54 -0400
Subject: [PATCH] Prevent corner-case core dump in rfree().
rfree() failed to cope with the case that pg_regcomp() had initialized the
regex_t struct but then failed to allocate any memory for re->re_guts (ie,
the first malloc call in pg_regcomp() failed). It would try to touch the
guts struct anyway, and thus dump core. This is a sufficiently narrow
corner case that it's not surprising it's never been seen in the field;
but still a bug is a bug, so patch all active branches.
Noted while investigating whether we need to call pg_regfree after a
failure return from pg_regcomp. Other than this bug, it turns out we
don't, so adjust comments appropriately.
---
src/backend/regex/regcomp.c | 24 +++++++++++++++---------
src/backend/utils/adt/regexp.c | 3 +--
2 files changed, 16 insertions(+), 11 deletions(-)
diff --git a/src/backend/regex/regcomp.c b/src/backend/regex/regcomp.c
index ceb6f0f873..5c5a9a8cd2 100644
--- a/src/backend/regex/regcomp.c
+++ b/src/backend/regex/regcomp.c
@@ -278,6 +278,9 @@ static struct fns functions = {
/*
* pg_regcomp - compile regular expression
+ *
+ * Note: on failure, no resources remain allocated, so pg_regfree()
+ * need not be applied to re.
*/
int
pg_regcomp(regex_t *re,
@@ -1870,15 +1873,18 @@ rfree(regex_t *re)
g = (struct guts *) re->re_guts;
re->re_guts = NULL;
re->re_fns = NULL;
- g->magic = 0;
- freecm(&g->cmap);
- if (g->tree != NULL)
- freesubre((struct vars *) NULL, g->tree);
- if (g->lacons != NULL)
- freelacons(g->lacons, g->nlacons);
- if (!NULLCNFA(g->search))
- freecnfa(&g->search);
- FREE(g);
+ if (g != NULL)
+ {
+ g->magic = 0;
+ freecm(&g->cmap);
+ if (g->tree != NULL)
+ freesubre((struct vars *) NULL, g->tree);
+ if (g->lacons != NULL)
+ freelacons(g->lacons, g->nlacons);
+ if (!NULLCNFA(g->search))
+ freecnfa(&g->search);
+ FREE(g);
+ }
}
#ifdef REG_DEBUG
diff --git a/src/backend/utils/adt/regexp.c b/src/backend/utils/adt/regexp.c
index 074142e798..92dfbb11ce 100644
--- a/src/backend/utils/adt/regexp.c
+++ b/src/backend/utils/adt/regexp.c
@@ -187,9 +187,8 @@ RE_compile_and_cache(text *text_re, int cflags, Oid collation)
if (regcomp_result != REG_OKAY)
{
- /* re didn't compile */
+ /* re didn't compile (no need for pg_regfree, if so) */
pg_regerror(regcomp_result, &re_temp.cre_re, errMsg, sizeof(errMsg));
- /* XXX should we pg_regfree here? */
ereport(ERROR,
(errcode(ERRCODE_INVALID_REGULAR_EXPRESSION),
errmsg("invalid regular expression: %s", errMsg)));