Mercurial > hg > nginx
view src/core/ngx_parse_time.c @ 8164:b71e69247483
Variables: avoid possible buffer overrun with some "$sent_http_*".
The existing logic to evaluate multi header "$sent_http_*" variables,
such as $sent_http_cache_control, as previously introduced in 1.23.0,
doesn't take into account that one or more elements can be cleared,
yet still present in a linked list, pointed to by the next field.
Such elements don't contribute to the resulting variable length, an
attempt to append a separator for them ends up in out of bounds write.
This is not possible with standard modules, though at least one third
party module is known to override multi header values this way, so it
makes sense to harden the logic.
The fix restores a generic boundary check.
author | Sergey Kandaurov <pluknet@nginx.com> |
---|---|
date | Mon, 01 May 2023 19:16:05 +0400 |
parents | b38a8f0ca4a2 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> static ngx_uint_t mday[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }; time_t ngx_parse_http_time(u_char *value, size_t len) { u_char *p, *end; ngx_int_t month; ngx_uint_t day, year, hour, min, sec; uint64_t time; enum { no = 0, rfc822, /* Tue, 10 Nov 2002 23:50:13 */ rfc850, /* Tuesday, 10-Dec-02 23:50:13 */ isoc /* Tue Dec 10 23:50:13 2002 */ } fmt; fmt = 0; end = value + len; #if (NGX_SUPPRESS_WARN) day = 32; year = 2038; #endif for (p = value; p < end; p++) { if (*p == ',') { break; } if (*p == ' ') { fmt = isoc; break; } } for (p++; p < end; p++) { if (*p != ' ') { break; } } if (end - p < 18) { return NGX_ERROR; } if (fmt != isoc) { if (*p < '0' || *p > '9' || *(p + 1) < '0' || *(p + 1) > '9') { return NGX_ERROR; } day = (*p - '0') * 10 + (*(p + 1) - '0'); p += 2; if (*p == ' ') { if (end - p < 18) { return NGX_ERROR; } fmt = rfc822; } else if (*p == '-') { fmt = rfc850; } else { return NGX_ERROR; } p++; } switch (*p) { case 'J': month = *(p + 1) == 'a' ? 0 : *(p + 2) == 'n' ? 5 : 6; break; case 'F': month = 1; break; case 'M': month = *(p + 2) == 'r' ? 2 : 4; break; case 'A': month = *(p + 1) == 'p' ? 3 : 7; break; case 'S': month = 8; break; case 'O': month = 9; break; case 'N': month = 10; break; case 'D': month = 11; break; default: return NGX_ERROR; } p += 3; if ((fmt == rfc822 && *p != ' ') || (fmt == rfc850 && *p != '-')) { return NGX_ERROR; } p++; if (fmt == rfc822) { if (*p < '0' || *p > '9' || *(p + 1) < '0' || *(p + 1) > '9' || *(p + 2) < '0' || *(p + 2) > '9' || *(p + 3) < '0' || *(p + 3) > '9') { return NGX_ERROR; } year = (*p - '0') * 1000 + (*(p + 1) - '0') * 100 + (*(p + 2) - '0') * 10 + (*(p + 3) - '0'); p += 4; } else if (fmt == rfc850) { if (*p < '0' || *p > '9' || *(p + 1) < '0' || *(p + 1) > '9') { return NGX_ERROR; } year = (*p - '0') * 10 + (*(p + 1) - '0'); year += (year < 70) ? 2000 : 1900; p += 2; } if (fmt == isoc) { if (*p == ' ') { p++; } if (*p < '0' || *p > '9') { return NGX_ERROR; } day = *p++ - '0'; if (*p != ' ') { if (*p < '0' || *p > '9') { return NGX_ERROR; } day = day * 10 + (*p++ - '0'); } if (end - p < 14) { return NGX_ERROR; } } if (*p++ != ' ') { return NGX_ERROR; } if (*p < '0' || *p > '9' || *(p + 1) < '0' || *(p + 1) > '9') { return NGX_ERROR; } hour = (*p - '0') * 10 + (*(p + 1) - '0'); p += 2; if (*p++ != ':') { return NGX_ERROR; } if (*p < '0' || *p > '9' || *(p + 1) < '0' || *(p + 1) > '9') { return NGX_ERROR; } min = (*p - '0') * 10 + (*(p + 1) - '0'); p += 2; if (*p++ != ':') { return NGX_ERROR; } if (*p < '0' || *p > '9' || *(p + 1) < '0' || *(p + 1) > '9') { return NGX_ERROR; } sec = (*p - '0') * 10 + (*(p + 1) - '0'); if (fmt == isoc) { p += 2; if (*p++ != ' ') { return NGX_ERROR; } if (*p < '0' || *p > '9' || *(p + 1) < '0' || *(p + 1) > '9' || *(p + 2) < '0' || *(p + 2) > '9' || *(p + 3) < '0' || *(p + 3) > '9') { return NGX_ERROR; } year = (*p - '0') * 1000 + (*(p + 1) - '0') * 100 + (*(p + 2) - '0') * 10 + (*(p + 3) - '0'); } if (hour > 23 || min > 59 || sec > 59) { return NGX_ERROR; } if (day == 29 && month == 1) { if ((year & 3) || ((year % 100 == 0) && (year % 400) != 0)) { return NGX_ERROR; } } else if (day > mday[month]) { return NGX_ERROR; } /* * shift new year to March 1 and start months from 1 (not 0), * it is needed for Gauss' formula */ if (--month <= 0) { month += 12; year -= 1; } /* Gauss' formula for Gregorian days since March 1, 1 BC */ time = (uint64_t) ( /* days in years including leap years since March 1, 1 BC */ 365 * year + year / 4 - year / 100 + year / 400 /* days before the month */ + 367 * month / 12 - 30 /* days before the day */ + day - 1 /* * 719527 days were between March 1, 1 BC and March 1, 1970, * 31 and 28 days were in January and February 1970 */ - 719527 + 31 + 28) * 86400 + hour * 3600 + min * 60 + sec; #if (NGX_TIME_T_SIZE <= 4) if (time > 0x7fffffff) { return NGX_ERROR; } #endif return (time_t) time; }