49340d93e
Denys Vlasenko
2024-07-09
Subject
awk: do not infinitely recurse getvar_s() if CONVFMT is set to a numeric value
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editors/awk.c+14 -6
| @@ -532,6 +532,7 @@ static const char vValues[] ALIGN1 = | |
| "%.6g\0" "%.6g\0" " \0" " \0" | |
| "\n\0" "\n\0" "\0" "\0" | |
| "\034\0" "\0" "\377"; | |
| + | #define str_percent_dot_6g vValues |
| /* hash size may grow to these values */ | |
| #define FIRST_PRIME 61 | |
| @@ -922,7 +923,7 @@ static double my_strtod_or_hexoct(char **pp) | |
| /* -------- working with variables (set/get/copy/etc) -------- */ | |
| - | static void fmt_num(const char *format, double n) |
| + | static const char *fmt_num(const char *format, double n) |
| { | |
| if (n == (long long)n) { | |
| snprintf(g_buf, MAXVARFMT, "%lld", (long long)n); | |
| @@ -939,6 +940,7 @@ static void fmt_num(const char *format, double n) | |
| syntax_error(EMSG_INV_FMT); | |
| } | |
| } | |
| + | return g_buf; |
| } | |
| static xhash *iamarray(var *a) | |
| @@ -1025,8 +1027,15 @@ static const char *getvar_s(var *v) | |
| { | |
| /* if v is numeric and has no cached string, convert it to string */ | |
| if ((v->type & (VF_NUMBER | VF_CACHED)) == VF_NUMBER) { | |
| - | fmt_num(getvar_s(intvar[CONVFMT]), v->number); |
| - | v->string = xstrdup(g_buf); |
| + | const char *convfmt = str_percent_dot_6g; /* "%.6g" */ |
| + | /* Get CONVFMT, unless we already recursed on it: |
| + | * someone might try to cause stack overflow by setting |
| + | * CONVFMT=9 (a numeric, not string, value) |
| + | */ |
| + | if (v != intvar[CONVFMT]) |
| + | convfmt = getvar_s(intvar[CONVFMT]); |
| + | /* Convert the value */ |
| + | v->string = xstrdup(fmt_num(convfmt, v->number)); |
| v->type |= VF_CACHED; | |
| } | |
| return (v->string == NULL) ? "" : v->string; | |
| @@ -3097,9 +3106,8 @@ static var *evaluate(node *op, var *res) | |
| for (;;) { | |
| var *v = evaluate(nextarg(&op1), TMPVAR0); | |
| if (v->type & VF_NUMBER) { | |
| - | fmt_num(getvar_s(intvar[OFMT]), |
| - | getvar_i(v)); |
| - | fputs(g_buf, F); |
| + | fputs(fmt_num(getvar_s(intvar[OFMT]), getvar_i(v)), |
| + | F); |
| } else { | |
| fputs(getvar_s(v), F); | |
| } | |