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unicode_case.c: defend against truncated UTF8.

Browse source 
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/c355354e6c3f4a7aafb047361b73db247260fca0.camel@j-davis.com
Backpatch-through: 17
This commit is contained in:
Jeff Davis 2026-07-07 13:35:23 -07:00
parent 177a2a2e39
commit 5e78ebca57
3 changed files with 56 additions and 10 deletions
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24
src/backend/utils/adt/formatting.c
View file

@ -1945,21 +1945,33 @@ initcap_wbnext(void *state)
while (wbstate->offset < wbstate->len &&
wbstate->str[wbstate->offset] != '\0')
{
pg_wchar u = utf8_to_unicode((unsigned char *) wbstate->str +
int ulen = pg_utf_mblen((const unsigned char *) wbstate->str +
wbstate->offset);
bool curr_alnum = pg_u_isalnum(u, true);
pg_wchar u;
bool curr_alnum;
size_t prev_offset = wbstate->offset;
/* invalid UTF8 */
if (wbstate->offset + ulen > wbstate->len)
{
wbstate->init = true;
wbstate->offset = wbstate->len;
return prev_offset;
}
u = utf8_to_unicode((const unsigned char *) wbstate->str +
wbstate->offset);
curr_alnum = pg_u_isalnum(u, true);
if (!wbstate->init || curr_alnum != wbstate->prev_alnum)
{
size_t prev_offset = wbstate->offset;
wbstate->init = true;
wbstate->offset += unicode_utf8len(u);
wbstate->offset += ulen;
wbstate->prev_alnum = curr_alnum;
return prev_offset;
}
wbstate->offset += unicode_utf8len(u);
wbstate->offset += ulen;
}
return wbstate->len;

9
src/common/unicode/case_test.c
View file

@ -169,6 +169,8 @@ test_strlower(const char *test_string, const char *expected)
static void
test_convert_case()
{
size_t needed;
/* test string with no case changes */
test_strlower("√∞", "√∞");
/* test string with case changes */
@ -176,6 +178,13 @@ test_convert_case()
/* test string with case changes and byte length changes */
test_strlower("ȺȺȺ", "ⱥⱥⱥ");
/* invalid UTF8: truncated multibyte sequence */
needed = unicode_strlower(NULL, 0, "abc\xCE", 4);
Assert(needed == 3);
/* invalid UTF8: invalid byte */
needed = unicode_strlower(NULL, 0, "abc\xF8xyz", 7);
Assert(needed == 3);
printf("case_test: convert_case: success\n");
}

33
src/common/unicode_case.c
View file

@ -126,6 +126,22 @@ unicode_strupper(char *dst, size_t dstsize, const char *src, ssize_t srclen)
return convert_case(dst, dstsize, src, srclen, CaseUpper, NULL, NULL);
}
/* local version of pg_utf_mblen() to be inlinable */
static int
utf8_mblen(const unsigned char *s)
{
if ((*s & 0x80) == 0)
return 1;
else if ((*s & 0xe0) == 0xc0)
return 2;
else if ((*s & 0xf0) == 0xe0)
return 3;
else if ((*s & 0xf8) == 0xf0)
return 4;
else
return -1;
}
/*
* If str_casekind is CaseLower or CaseUpper, map each character in the string
* for which a mapping is available.
@ -152,11 +168,18 @@ convert_case(char *dst, size_t dstsize, const char *src, ssize_t srclen,
Assert(boundary == 0); /* start of text is always a boundary */
}
while ((srclen < 0 || srcoff < srclen) && src[srcoff] != '\0')
srclen = (srclen < 0) ? strlen(src) : srclen;
while (srcoff < srclen && src[srcoff] != '\0')
{
pg_wchar u1 = utf8_to_unicode((unsigned char *) src + srcoff);
int u1len = unicode_utf8len(u1);
const pg_case_map *casemap = find_case_map(u1);
int u1len = utf8_mblen((const unsigned char *) src + srcoff);
pg_wchar u1;
const pg_case_map *casemap;
/* invalid UTF8 */
if (u1len < 0 || srcoff + u1len > srclen)
break;
u1 = utf8_to_unicode((const unsigned char *) src + srcoff);
if (str_casekind == CaseTitle)
{
@ -169,6 +192,8 @@ convert_case(char *dst, size_t dstsize, const char *src, ssize_t srclen,
chr_casekind = CaseLower;
}
casemap = find_case_map(u1);
/* perform mapping, update result_len, and write to dst */
if (casemap)
{