Mercurial > hg > nginx-quic
view src/core/ngx_parse.c @ 7977:7731c710796f
Memcached: protect from too long responses.
If a memcached response was followed by a correct trailer, and then
the NUL character followed by some extra data - this was accepted by
the trailer checking code. This in turn resulted in ctx->rest underflow
and caused negative size buffer on the next reading from the upstream,
followed by the "negative size buf in writer" alert.
Fix is to always check for too long responses, so a correct trailer cannot
be followed by extra data.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 06 Jul 2020 18:36:17 +0300 |
parents | 87cf6ddb41c2 |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> ssize_t ngx_parse_size(ngx_str_t *line) { u_char unit; size_t len; ssize_t size, scale, max; len = line->len; if (len == 0) { return NGX_ERROR; } unit = line->data[len - 1]; switch (unit) { case 'K': case 'k': len--; max = NGX_MAX_SIZE_T_VALUE / 1024; scale = 1024; break; case 'M': case 'm': len--; max = NGX_MAX_SIZE_T_VALUE / (1024 * 1024); scale = 1024 * 1024; break; default: max = NGX_MAX_SIZE_T_VALUE; scale = 1; } size = ngx_atosz(line->data, len); if (size == NGX_ERROR || size > max) { return NGX_ERROR; } size *= scale; return size; } off_t ngx_parse_offset(ngx_str_t *line) { u_char unit; off_t offset, scale, max; size_t len; len = line->len; if (len == 0) { return NGX_ERROR; } unit = line->data[len - 1]; switch (unit) { case 'K': case 'k': len--; max = NGX_MAX_OFF_T_VALUE / 1024; scale = 1024; break; case 'M': case 'm': len--; max = NGX_MAX_OFF_T_VALUE / (1024 * 1024); scale = 1024 * 1024; break; case 'G': case 'g': len--; max = NGX_MAX_OFF_T_VALUE / (1024 * 1024 * 1024); scale = 1024 * 1024 * 1024; break; default: max = NGX_MAX_OFF_T_VALUE; scale = 1; } offset = ngx_atoof(line->data, len); if (offset == NGX_ERROR || offset > max) { return NGX_ERROR; } offset *= scale; return offset; } ngx_int_t ngx_parse_time(ngx_str_t *line, ngx_uint_t is_sec) { u_char *p, *last; ngx_int_t value, total, scale; ngx_int_t max, cutoff, cutlim; ngx_uint_t valid; enum { st_start = 0, st_year, st_month, st_week, st_day, st_hour, st_min, st_sec, st_msec, st_last } step; valid = 0; value = 0; total = 0; cutoff = NGX_MAX_INT_T_VALUE / 10; cutlim = NGX_MAX_INT_T_VALUE % 10; step = is_sec ? st_start : st_month; p = line->data; last = p + line->len; while (p < last) { if (*p >= '0' && *p <= '9') { if (value >= cutoff && (value > cutoff || *p - '0' > cutlim)) { return NGX_ERROR; } value = value * 10 + (*p++ - '0'); valid = 1; continue; } switch (*p++) { case 'y': if (step > st_start) { return NGX_ERROR; } step = st_year; max = NGX_MAX_INT_T_VALUE / (60 * 60 * 24 * 365); scale = 60 * 60 * 24 * 365; break; case 'M': if (step >= st_month) { return NGX_ERROR; } step = st_month; max = NGX_MAX_INT_T_VALUE / (60 * 60 * 24 * 30); scale = 60 * 60 * 24 * 30; break; case 'w': if (step >= st_week) { return NGX_ERROR; } step = st_week; max = NGX_MAX_INT_T_VALUE / (60 * 60 * 24 * 7); scale = 60 * 60 * 24 * 7; break; case 'd': if (step >= st_day) { return NGX_ERROR; } step = st_day; max = NGX_MAX_INT_T_VALUE / (60 * 60 * 24); scale = 60 * 60 * 24; break; case 'h': if (step >= st_hour) { return NGX_ERROR; } step = st_hour; max = NGX_MAX_INT_T_VALUE / (60 * 60); scale = 60 * 60; break; case 'm': if (p < last && *p == 's') { if (is_sec || step >= st_msec) { return NGX_ERROR; } p++; step = st_msec; max = NGX_MAX_INT_T_VALUE; scale = 1; break; } if (step >= st_min) { return NGX_ERROR; } step = st_min; max = NGX_MAX_INT_T_VALUE / 60; scale = 60; break; case 's': if (step >= st_sec) { return NGX_ERROR; } step = st_sec; max = NGX_MAX_INT_T_VALUE; scale = 1; break; case ' ': if (step >= st_sec) { return NGX_ERROR; } step = st_last; max = NGX_MAX_INT_T_VALUE; scale = 1; break; default: return NGX_ERROR; } if (step != st_msec && !is_sec) { scale *= 1000; max /= 1000; } if (value > max) { return NGX_ERROR; } value *= scale; if (total > NGX_MAX_INT_T_VALUE - value) { return NGX_ERROR; } total += value; value = 0; while (p < last && *p == ' ') { p++; } } if (!valid) { return NGX_ERROR; } if (!is_sec) { if (value > NGX_MAX_INT_T_VALUE / 1000) { return NGX_ERROR; } value *= 1000; } if (total > NGX_MAX_INT_T_VALUE - value) { return NGX_ERROR; } return total + value; }