Mercurial > hg > nginx
view src/core/ngx_parse_time.c @ 7054:e02555553d0b
Range filter: protect from total size overflows.
The overflow can be used to circumvent the restriction on total size of
ranges introduced in c2a91088b0c0 (1.1.2). Additionally, overflow
allows producing ranges with negative start (such ranges can be created
by using a suffix, "bytes=-100"; normally this results in 200 due to
the total size check). These can result in the following errors in logs:
[crit] ... pread() ... failed (22: Invalid argument)
[alert] ... sendfile() failed (22: Invalid argument)
When using cache, it can be also used to reveal cache file header.
It is believed that there are no other negative effects, at least with
standard nginx modules.
In theory, this can also result in memory disclosure and/or segmentation
faults if multiple ranges are allowed, and the response is returned in a
single in-memory buffer. This never happens with standard nginx modules
though, as well as known 3rd party modules.
Fix is to properly protect from possible overflow when incrementing size.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Tue, 11 Jul 2017 16:06:23 +0300 |
parents | 2cd019520210 |
children | e3723f2a11b7 |
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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; }