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Fix memory leakage in ICU encoding conversion, and other code review.

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Callers of icu_to_uchar() neglected to pfree the result string when done
with it.  This results in catastrophic memory leaks in varstr_cmp(),
because of our prevailing assumption that btree comparison functions don't
leak memory.  For safety, make all the call sites clean up leaks, though
I suspect that we could get away without it in formatting.c.  I audited
callers of icu_from_uchar() as well, but found no places that seemed to
have a comparable issue.

Add function API specifications for icu_to_uchar() and icu_from_uchar();
the lack of any thought-through specification is perhaps not unrelated
to the existence of this bug in the first place.  Fix icu_to_uchar()
to guarantee a nul-terminated result; although no existing caller appears
to care, the fact that it would have been nul-terminated except in
extreme corner cases seems ideally designed to bite someone on the rear
someday.  Fix ucnv_fromUChars() destCapacity argument --- in the worst
case, that could perhaps have led to a non-nul-terminated result, too.
Fix icu_from_uchar() to have a more reasonable definition of the function
result --- no callers are actually paying attention, so this isn't a live
bug, but it's certainly sloppily designed.  Const-ify icu_from_uchar()'s
input string for consistency.

That is not the end of what needs to be done to these functions, but
it's as much as I have the patience for right now.

Discussion: https://postgr.es/m/1955.1498181798@sss.pgh.pa.us
This commit is contained in:
Tom Lane
2017-06-23 12:22:06 -04:00
parent 8be8510cf8
commit b6159202c9
5 changed files with 60 additions and 11 deletions
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15
src/backend/commands/collationcmds.c
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@ -381,6 +381,10 @@ normalize_libc_locale_name(char *new, const char *old)
#ifdef USE_ICU
/*
* Get the ICU language tag for a locale name.
* The result is a palloc'd string.
*/
static char *
get_icu_language_tag(const char *localename)
{
@ -397,7 +401,10 @@ get_icu_language_tag(const char *localename)
return pstrdup(buf);
}
/*
* Get a comment (specifically, the display name) for an ICU locale.
* The result is a palloc'd string.
*/
static char *
get_icu_locale_comment(const char *localename)
{
@ -407,10 +414,12 @@ get_icu_locale_comment(const char *localename)
char *result;
status = U_ZERO_ERROR;
len_uchar = uloc_getDisplayName(localename, "en", &displayname[0], sizeof(displayname), &status);
len_uchar = uloc_getDisplayName(localename, "en",
&displayname[0], sizeof(displayname),
&status);
if (U_FAILURE(status))
ereport(ERROR,
(errmsg("could get display name for locale \"%s\": %s",
(errmsg("could not get display name for locale \"%s\": %s",
localename, u_errorName(status))));
icu_from_uchar(&result, displayname, len_uchar);