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Guard against overly-long numeric formatting symbols from locale.

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to_char() allocates its output buffer with 8 bytes per formatting
code in the pattern.  If the locale's currency symbol, thousands
separator, or decimal or sign symbol is more than 8 bytes long,
in principle we could overrun the output buffer.  No such locales
exist in the real world, so it seems sufficient to truncate the
symbol if we do see it's too long.

Reported-by: Xint Code
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/638232.1776790821@sss.pgh.pa.us
Backpatch-through: 14
This commit is contained in:
Tom Lane 2026-04-22 12:41:00 -04:00
parent d7970e7e95
commit a50777680f
1 changed files with 43 additions and 18 deletions
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61
src/backend/utils/adt/formatting.c
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@ -1114,6 +1114,7 @@ static void NUM_prepare_locale(NUMProc *Np);
static const char *get_last_relevant_decnum(const char *num);
static void NUM_numpart_from_char(NUMProc *Np, int id, size_t input_len);
static void NUM_numpart_to_char(NUMProc *Np, int id);
static void NUM_add_locale_symbol(NUMProc *Np, const char *pattern);
static char *NUM_processor(FormatNode *node, NUMDesc *Num, char *inout,
char *number, size_t input_len, int to_char_out_pre_spaces,
int sign, bool is_to_char, Oid collid);
@ -5568,11 +5569,9 @@ NUM_numpart_to_char(NUMProc *Np, int id)
{
if (Np->Num->lsign == NUM_LSIGN_PRE)
{
if (Np->sign == '-')
strcpy(Np->inout_p, Np->L_negative_sign);
else
strcpy(Np->inout_p, Np->L_positive_sign);
Np->inout_p += strlen(Np->inout_p);
NUM_add_locale_symbol(Np, (Np->sign == '-') ?
Np->L_negative_sign :
Np->L_positive_sign);
Np->sign_wrote = true;
}
}
@ -5637,8 +5636,7 @@ NUM_numpart_to_char(NUMProc *Np, int id)
{
if (!Np->last_relevant || *Np->last_relevant != '.')
{
strcpy(Np->inout_p, Np->decimal); /* Write DEC/D */
Np->inout_p += strlen(Np->inout_p);
NUM_add_locale_symbol(Np, Np->decimal); /* Write DEC/D */
}
/*
@ -5647,8 +5645,7 @@ NUM_numpart_to_char(NUMProc *Np, int id)
else if (IS_FILLMODE(Np->Num) &&
Np->last_relevant && *Np->last_relevant == '.')
{
strcpy(Np->inout_p, Np->decimal); /* Write DEC/D */
Np->inout_p += strlen(Np->inout_p);
NUM_add_locale_symbol(Np, Np->decimal); /* Write DEC/D */
}
}
else
@ -5706,11 +5703,9 @@ NUM_numpart_to_char(NUMProc *Np, int id)
}
else if (IS_LSIGN(Np->Num) && Np->Num->lsign == NUM_LSIGN_POST)
{
if (Np->sign == '-')
strcpy(Np->inout_p, Np->L_negative_sign);
else
strcpy(Np->inout_p, Np->L_positive_sign);
Np->inout_p += strlen(Np->inout_p);
NUM_add_locale_symbol(Np, (Np->sign == '-') ?
Np->L_negative_sign :
Np->L_positive_sign);
}
}
}
@ -5718,6 +5713,23 @@ NUM_numpart_to_char(NUMProc *Np, int id)
++Np->num_curr;
}
/*
* Append locale-specific symbol to Np->inout.
* Note we don't null-terminate the output
*/
static void
NUM_add_locale_symbol(NUMProc *Np, const char *pattern)
{
size_t pattern_len = strlen(pattern);
/* Truncate symbol if it's potentially too long */
if (unlikely(pattern_len > NUM_MAX_ITEM_SIZ))
pattern_len = pg_mbcliplen(pattern, pattern_len,
NUM_MAX_ITEM_SIZ);
memcpy(Np->inout_p, pattern, pattern_len);
Np->inout_p += pattern_len;
}
/*
* Skip over "n" input characters, but only if they aren't numeric data
*/
@ -5965,6 +5977,10 @@ NUM_processor(FormatNode *node, NUMDesc *Num, char *inout,
pattern_len = strlen(pattern);
if (Np->is_to_char)
{
/* Truncate symbol if it's potentially too long */
if (unlikely(pattern_len > NUM_MAX_ITEM_SIZ))
pattern_len = pg_mbcliplen(pattern, pattern_len,
NUM_MAX_ITEM_SIZ);
if (!Np->num_in)
{
if (IS_FILLMODE(Np->Num))
@ -5972,19 +5988,21 @@ NUM_processor(FormatNode *node, NUMDesc *Num, char *inout,
else
{
/* just in case there are MB chars */
pattern_len = pg_mbstrlen(pattern);
pattern_len = pg_mbstrlen_with_len(pattern,
pattern_len);
memset(Np->inout_p, ' ', pattern_len);
Np->inout_p += pattern_len - 1;
}
}
else
{
strcpy(Np->inout_p, pattern);
memcpy(Np->inout_p, pattern, pattern_len);
Np->inout_p += pattern_len - 1;
}
}
else
{
/* Here we do not truncate the symbol ... */
if (!Np->num_in)
{
if (IS_FILLMODE(Np->Num))
@ -6009,11 +6027,18 @@ NUM_processor(FormatNode *node, NUMDesc *Num, char *inout,
pattern = Np->L_currency_symbol;
if (Np->is_to_char)
{
strcpy(Np->inout_p, pattern);
Np->inout_p += strlen(pattern) - 1;
/* Truncate symbol if it's potentially too long */
pattern_len = strlen(pattern);
if (unlikely(pattern_len > NUM_MAX_ITEM_SIZ))
pattern_len = pg_mbcliplen(pattern, pattern_len,
NUM_MAX_ITEM_SIZ);
memcpy(Np->inout_p, pattern, pattern_len);
Np->inout_p += pattern_len - 1;
}
else
{
/* Here we do not truncate the symbol ... */
NUM_eat_non_data_chars(Np, pg_mbstrlen(pattern), input_len);
continue;
}