Hello! On Wed, Oct 19, 2016 at 02:43:24PM +0800, 胡聪 (hucc) wrote:
> Hello! > > > Thanks for reminding me! Illegal character should be checked > also error detection in configration parser is needed. > > > Considering that ngx_atofp() was used in some 3rd party modules, > Would nginx-devel accept a new function like ngx_ato??() or > lround(strtod()), or just let strtod() alone? Using strtod() should be avoided as it has other problems, see https://trac.nginx.org/nginx/ticket/475. That is, an additional variant of ngx_atofp() is a way to go. Last time we've looked into this, we've stumbled upon selecting a proper name for the additional function. Looking into this again I tend to think that proper solution would be to use a special function withing the ngx_http_mp4_module itself. Patch below. # HG changeset patch # User Maxim Dounin <mdou...@mdounin.ru> # Date 1477416871 -10800 # Tue Oct 25 20:34:31 2016 +0300 # Node ID 16dae7d3b770c63dc16ac06312a66c1bafc3308f # Parent 56d6bfe6b609c565a9f500bde573fd9b488ff960 Mp4: introduced custom version of ngx_atofp(). This allows to correctly parse "start" and "end" arguments without null-termination (ticket #475), and also fixes rounding errors observed with strtod() when using i387 instructions. diff --git a/src/http/modules/ngx_http_mp4_module.c b/src/http/modules/ngx_http_mp4_module.c --- a/src/http/modules/ngx_http_mp4_module.c +++ b/src/http/modules/ngx_http_mp4_module.c @@ -216,6 +216,7 @@ typedef struct { static ngx_int_t ngx_http_mp4_handler(ngx_http_request_t *r); +static ngx_int_t ngx_http_mp4_atofp(u_char *line, size_t n, size_t point); static ngx_int_t ngx_http_mp4_process(ngx_http_mp4_file_t *mp4); static ngx_int_t ngx_http_mp4_read_atom(ngx_http_mp4_file_t *mp4, @@ -537,26 +538,15 @@ ngx_http_mp4_handler(ngx_http_request_t /* * A Flash player may send start value with a lot of digits - * after dot so strtod() is used instead of atofp(). NaNs and - * infinities become negative numbers after (int) conversion. + * after dot so a custom function is used instead of ngx_atofp(). */ - ngx_set_errno(0); - start = (int) (strtod((char *) value.data, NULL) * 1000); - - if (ngx_errno != 0) { - start = -1; - } + start = ngx_http_mp4_atofp(value.data, value.len, 3); } if (ngx_http_arg(r, (u_char *) "end", 3, &value) == NGX_OK) { - ngx_set_errno(0); - end = (int) (strtod((char *) value.data, NULL) * 1000); - - if (ngx_errno != 0) { - end = -1; - } + end = ngx_http_mp4_atofp(value.data, value.len, 3); if (end > 0) { if (start < 0) { @@ -687,6 +677,62 @@ ngx_http_mp4_handler(ngx_http_request_t static ngx_int_t +ngx_http_mp4_atofp(u_char *line, size_t n, size_t point) +{ + ngx_int_t value, cutoff, cutlim; + ngx_uint_t dot; + + /* same as ngx_atofp(), but allows additional digits */ + + if (n == 0) { + return NGX_ERROR; + } + + cutoff = NGX_MAX_INT_T_VALUE / 10; + cutlim = NGX_MAX_INT_T_VALUE % 10; + + dot = 0; + + for (value = 0; n--; line++) { + + if (point == 0) { + break; + } + + if (*line == '.') { + if (dot) { + return NGX_ERROR; + } + + dot = 1; + continue; + } + + if (*line < '0' || *line > '9') { + return NGX_ERROR; + } + + if (value >= cutoff && (value > cutoff || *line - '0' > cutlim)) { + return NGX_ERROR; + } + + value = value * 10 + (*line - '0'); + point -= dot; + } + + while (point--) { + if (value > cutoff) { + return NGX_ERROR; + } + + value = value * 10; + } + + return value; +} + + +static ngx_int_t ngx_http_mp4_process(ngx_http_mp4_file_t *mp4) { off_t start_offset, end_offset, adjustment; -- Maxim Dounin http://nginx.org/ _______________________________________________ nginx-devel mailing list nginx-devel@nginx.org http://mailman.nginx.org/mailman/listinfo/nginx-devel
