Mercurial > hg > nginx-quic
view src/http/modules/ngx_http_slice_filter_module.c @ 7629:f47f7d3d1bfa
Mp4: fixed possible chunk offset overflow.
In "co64" atom chunk start offset is a 64-bit unsigned integer. When trimming
the "mdat" atom, chunk offsets are casted to off_t values which are typically
64-bit signed integers. A specially crafted mp4 file with huge chunk offsets
may lead to off_t overflow and result in negative trim boundaries.
The consequences of the overflow are:
- Incorrect Content-Length header value in the response.
- Negative left boundary of the response file buffer holding the trimmed "mdat".
This leads to pread()/sendfile() errors followed by closing the client
connection.
On rare systems where off_t is a 32-bit integer, this scenario is also feasible
with the "stco" atom.
The fix is to add checks which make sure data chunks referenced by each track
are within the mp4 file boundaries. Additionally a few more checks are added to
ensure mp4 file consistency and log errors.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Wed, 26 Feb 2020 15:10:46 +0300 |
parents | f583559aadc7 |
children | 32a343635b50 |
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/* * Copyright (C) Roman Arutyunyan * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_http.h> typedef struct { size_t size; } ngx_http_slice_loc_conf_t; typedef struct { off_t start; off_t end; ngx_str_t range; ngx_str_t etag; unsigned last:1; unsigned active:1; ngx_http_request_t *sr; } ngx_http_slice_ctx_t; typedef struct { off_t start; off_t end; off_t complete_length; } ngx_http_slice_content_range_t; static ngx_int_t ngx_http_slice_header_filter(ngx_http_request_t *r); static ngx_int_t ngx_http_slice_body_filter(ngx_http_request_t *r, ngx_chain_t *in); static ngx_int_t ngx_http_slice_parse_content_range(ngx_http_request_t *r, ngx_http_slice_content_range_t *cr); static ngx_int_t ngx_http_slice_range_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data); static off_t ngx_http_slice_get_start(ngx_http_request_t *r); static void *ngx_http_slice_create_loc_conf(ngx_conf_t *cf); static char *ngx_http_slice_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child); static ngx_int_t ngx_http_slice_add_variables(ngx_conf_t *cf); static ngx_int_t ngx_http_slice_init(ngx_conf_t *cf); static ngx_command_t ngx_http_slice_filter_commands[] = { { ngx_string("slice"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_conf_set_size_slot, NGX_HTTP_LOC_CONF_OFFSET, offsetof(ngx_http_slice_loc_conf_t, size), NULL }, ngx_null_command }; static ngx_http_module_t ngx_http_slice_filter_module_ctx = { ngx_http_slice_add_variables, /* preconfiguration */ ngx_http_slice_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_slice_create_loc_conf, /* create location configuration */ ngx_http_slice_merge_loc_conf /* merge location configuration */ }; ngx_module_t ngx_http_slice_filter_module = { NGX_MODULE_V1, &ngx_http_slice_filter_module_ctx, /* module context */ ngx_http_slice_filter_commands, /* module directives */ NGX_HTTP_MODULE, /* module type */ NULL, /* init master */ NULL, /* init module */ NULL, /* init process */ NULL, /* init thread */ NULL, /* exit thread */ NULL, /* exit process */ NULL, /* exit master */ NGX_MODULE_V1_PADDING }; static ngx_str_t ngx_http_slice_range_name = ngx_string("slice_range"); static ngx_http_output_header_filter_pt ngx_http_next_header_filter; static ngx_http_output_body_filter_pt ngx_http_next_body_filter; static ngx_int_t ngx_http_slice_header_filter(ngx_http_request_t *r) { off_t end; ngx_int_t rc; ngx_table_elt_t *h; ngx_http_slice_ctx_t *ctx; ngx_http_slice_loc_conf_t *slcf; ngx_http_slice_content_range_t cr; ctx = ngx_http_get_module_ctx(r, ngx_http_slice_filter_module); if (ctx == NULL) { return ngx_http_next_header_filter(r); } if (r->headers_out.status != NGX_HTTP_PARTIAL_CONTENT) { if (r == r->main) { ngx_http_set_ctx(r, NULL, ngx_http_slice_filter_module); return ngx_http_next_header_filter(r); } ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "unexpected status code %ui in slice response", r->headers_out.status); return NGX_ERROR; } h = r->headers_out.etag; if (ctx->etag.len) { if (h == NULL || h->value.len != ctx->etag.len || ngx_strncmp(h->value.data, ctx->etag.data, ctx->etag.len) != 0) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "etag mismatch in slice response"); return NGX_ERROR; } } if (h) { ctx->etag = h->value; } if (ngx_http_slice_parse_content_range(r, &cr) != NGX_OK) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "invalid range in slice response"); return NGX_ERROR; } if (cr.complete_length == -1) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "no complete length in slice response"); return NGX_ERROR; } ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http slice response range: %O-%O/%O", cr.start, cr.end, cr.complete_length); slcf = ngx_http_get_module_loc_conf(r, ngx_http_slice_filter_module); end = ngx_min(cr.start + (off_t) slcf->size, cr.complete_length); if (cr.start != ctx->start || cr.end != end) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "unexpected range in slice response: %O-%O", cr.start, cr.end); return NGX_ERROR; } ctx->start = end; ctx->active = 1; r->headers_out.status = NGX_HTTP_OK; r->headers_out.status_line.len = 0; r->headers_out.content_length_n = cr.complete_length; r->headers_out.content_offset = cr.start; r->headers_out.content_range->hash = 0; r->headers_out.content_range = NULL; r->allow_ranges = 1; r->subrequest_ranges = 1; r->single_range = 1; rc = ngx_http_next_header_filter(r); if (r != r->main) { return rc; } r->preserve_body = 1; if (r->headers_out.status == NGX_HTTP_PARTIAL_CONTENT) { if (ctx->start + (off_t) slcf->size <= r->headers_out.content_offset) { ctx->start = slcf->size * (r->headers_out.content_offset / slcf->size); } ctx->end = r->headers_out.content_offset + r->headers_out.content_length_n; } else { ctx->end = cr.complete_length; } return rc; } static ngx_int_t ngx_http_slice_body_filter(ngx_http_request_t *r, ngx_chain_t *in) { ngx_int_t rc; ngx_chain_t *cl; ngx_http_slice_ctx_t *ctx; ngx_http_slice_loc_conf_t *slcf; ctx = ngx_http_get_module_ctx(r, ngx_http_slice_filter_module); if (ctx == NULL || r != r->main) { return ngx_http_next_body_filter(r, in); } for (cl = in; cl; cl = cl->next) { if (cl->buf->last_buf) { cl->buf->last_buf = 0; cl->buf->last_in_chain = 1; cl->buf->sync = 1; ctx->last = 1; } } rc = ngx_http_next_body_filter(r, in); if (rc == NGX_ERROR || !ctx->last) { return rc; } if (ctx->sr && !ctx->sr->done) { return rc; } if (!ctx->active) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "missing slice response"); return NGX_ERROR; } if (ctx->start >= ctx->end) { ngx_http_set_ctx(r, NULL, ngx_http_slice_filter_module); ngx_http_send_special(r, NGX_HTTP_LAST); return rc; } if (r->buffered) { return rc; } if (ngx_http_subrequest(r, &r->uri, &r->args, &ctx->sr, NULL, NGX_HTTP_SUBREQUEST_CLONE) != NGX_OK) { return NGX_ERROR; } ngx_http_set_ctx(ctx->sr, ctx, ngx_http_slice_filter_module); slcf = ngx_http_get_module_loc_conf(r, ngx_http_slice_filter_module); ctx->range.len = ngx_sprintf(ctx->range.data, "bytes=%O-%O", ctx->start, ctx->start + (off_t) slcf->size - 1) - ctx->range.data; ctx->active = 0; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http slice subrequest: \"%V\"", &ctx->range); return rc; } static ngx_int_t ngx_http_slice_parse_content_range(ngx_http_request_t *r, ngx_http_slice_content_range_t *cr) { off_t start, end, complete_length, cutoff, cutlim; u_char *p; ngx_table_elt_t *h; h = r->headers_out.content_range; if (h == NULL || h->value.len < 7 || ngx_strncmp(h->value.data, "bytes ", 6) != 0) { return NGX_ERROR; } p = h->value.data + 6; cutoff = NGX_MAX_OFF_T_VALUE / 10; cutlim = NGX_MAX_OFF_T_VALUE % 10; start = 0; end = 0; complete_length = 0; while (*p == ' ') { p++; } if (*p < '0' || *p > '9') { return NGX_ERROR; } while (*p >= '0' && *p <= '9') { if (start >= cutoff && (start > cutoff || *p - '0' > cutlim)) { return NGX_ERROR; } start = start * 10 + (*p++ - '0'); } while (*p == ' ') { p++; } if (*p++ != '-') { return NGX_ERROR; } while (*p == ' ') { p++; } if (*p < '0' || *p > '9') { return NGX_ERROR; } while (*p >= '0' && *p <= '9') { if (end >= cutoff && (end > cutoff || *p - '0' > cutlim)) { return NGX_ERROR; } end = end * 10 + (*p++ - '0'); } end++; while (*p == ' ') { p++; } if (*p++ != '/') { return NGX_ERROR; } while (*p == ' ') { p++; } if (*p != '*') { if (*p < '0' || *p > '9') { return NGX_ERROR; } while (*p >= '0' && *p <= '9') { if (complete_length >= cutoff && (complete_length > cutoff || *p - '0' > cutlim)) { return NGX_ERROR; } complete_length = complete_length * 10 + (*p++ - '0'); } } else { complete_length = -1; p++; } while (*p == ' ') { p++; } if (*p != '\0') { return NGX_ERROR; } cr->start = start; cr->end = end; cr->complete_length = complete_length; return NGX_OK; } static ngx_int_t ngx_http_slice_range_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data) { u_char *p; ngx_http_slice_ctx_t *ctx; ngx_http_slice_loc_conf_t *slcf; ctx = ngx_http_get_module_ctx(r, ngx_http_slice_filter_module); if (ctx == NULL) { if (r != r->main || r->headers_out.status) { v->not_found = 1; return NGX_OK; } slcf = ngx_http_get_module_loc_conf(r, ngx_http_slice_filter_module); if (slcf->size == 0) { v->not_found = 1; return NGX_OK; } ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_slice_ctx_t)); if (ctx == NULL) { return NGX_ERROR; } ngx_http_set_ctx(r, ctx, ngx_http_slice_filter_module); p = ngx_pnalloc(r->pool, sizeof("bytes=-") - 1 + 2 * NGX_OFF_T_LEN); if (p == NULL) { return NGX_ERROR; } ctx->start = slcf->size * (ngx_http_slice_get_start(r) / slcf->size); ctx->range.data = p; ctx->range.len = ngx_sprintf(p, "bytes=%O-%O", ctx->start, ctx->start + (off_t) slcf->size - 1) - p; } v->data = ctx->range.data; v->valid = 1; v->not_found = 0; v->no_cacheable = 1; v->len = ctx->range.len; return NGX_OK; } static off_t ngx_http_slice_get_start(ngx_http_request_t *r) { off_t start, cutoff, cutlim; u_char *p; ngx_table_elt_t *h; if (r->headers_in.if_range) { return 0; } h = r->headers_in.range; if (h == NULL || h->value.len < 7 || ngx_strncasecmp(h->value.data, (u_char *) "bytes=", 6) != 0) { return 0; } p = h->value.data + 6; if (ngx_strchr(p, ',')) { return 0; } while (*p == ' ') { p++; } if (*p == '-') { return 0; } cutoff = NGX_MAX_OFF_T_VALUE / 10; cutlim = NGX_MAX_OFF_T_VALUE % 10; start = 0; while (*p >= '0' && *p <= '9') { if (start >= cutoff && (start > cutoff || *p - '0' > cutlim)) { return 0; } start = start * 10 + (*p++ - '0'); } return start; } static void * ngx_http_slice_create_loc_conf(ngx_conf_t *cf) { ngx_http_slice_loc_conf_t *slcf; slcf = ngx_palloc(cf->pool, sizeof(ngx_http_slice_loc_conf_t)); if (slcf == NULL) { return NULL; } slcf->size = NGX_CONF_UNSET_SIZE; return slcf; } static char * ngx_http_slice_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child) { ngx_http_slice_loc_conf_t *prev = parent; ngx_http_slice_loc_conf_t *conf = child; ngx_conf_merge_size_value(conf->size, prev->size, 0); return NGX_CONF_OK; } static ngx_int_t ngx_http_slice_add_variables(ngx_conf_t *cf) { ngx_http_variable_t *var; var = ngx_http_add_variable(cf, &ngx_http_slice_range_name, 0); if (var == NULL) { return NGX_ERROR; } var->get_handler = ngx_http_slice_range_variable; return NGX_OK; } static ngx_int_t ngx_http_slice_init(ngx_conf_t *cf) { ngx_http_next_header_filter = ngx_http_top_header_filter; ngx_http_top_header_filter = ngx_http_slice_header_filter; ngx_http_next_body_filter = ngx_http_top_body_filter; ngx_http_top_body_filter = ngx_http_slice_body_filter; return NGX_OK; }