From 8a6f08c0c7c3769ba32e302c95c7950179e5b87e Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Wed, 22 Apr 2026 12:41:01 -0400 Subject: [PATCH] Guard against overly-long numeric formatting symbols from locale. 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 Discussion: https://postgr.es/m/638232.1776790821@sss.pgh.pa.us Backpatch-through: 14 --- src/backend/utils/adt/formatting.c | 61 +++++++++++++++++++++--------- 1 file changed, 43 insertions(+), 18 deletions(-) diff --git a/src/backend/utils/adt/formatting.c b/src/backend/utils/adt/formatting.c index a157c3c8764..2e456025e96 100644 --- a/src/backend/utils/adt/formatting.c +++ b/src/backend/utils/adt/formatting.c @@ -1075,6 +1075,7 @@ static void NUM_prepare_locale(NUMProc *Np); static char *get_last_relevant_decnum(char *num); static void NUM_numpart_from_char(NUMProc *Np, int id, int 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, int input_len, int to_char_out_pre_spaces, int sign, bool is_to_char, Oid collid); @@ -5408,11 +5409,9 @@ 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; } } @@ -5477,8 +5476,7 @@ 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 */ } /* @@ -5487,8 +5485,7 @@ 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 @@ -5546,11 +5543,9 @@ 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); } } } @@ -5558,6 +5553,23 @@ 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 */ @@ -5832,6 +5844,10 @@ 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)) @@ -5839,19 +5855,21 @@ 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)) @@ -5876,11 +5894,18 @@ 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; }