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commit    e1e60f148a3aa937f1bf92dd50bb4b24051fd0e2
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Wed Apr 22 16:41:01 2026 +0000
First released in: 14.23, 15.18, 16.14, 17.10, 18.4

    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 <tgl@sss.pgh.pa.us>
    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 e18a3d07c8c..764f386605c 100644 --- a/src/backend/utils/adt/formatting.c +++ b/src/backend/utils/adt/formatting.c @@ -1068,6 +1068,7 @@ 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); @@ -5423,11 +5424,9 @@ 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; } } @@ -5492,8 +5491,7 @@ 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 */ } /* @@ -5502,8 +5500,7 @@ 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 @@ -5561,11 +5558,9 @@ 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); } } } @@ -5573,6 +5568,23 @@ 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 */ @@ -5843,6 +5855,10 @@ 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)) @@ -5850,19 +5866,21 @@ 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)) @@ -5887,11 +5905,18 @@ 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; } [parent: 42383d32d78a]