Mercurial > hg > nginx
view src/core/ngx_palloc.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 | ad2360782ecd |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> static ngx_inline void *ngx_palloc_small(ngx_pool_t *pool, size_t size, ngx_uint_t align); static void *ngx_palloc_block(ngx_pool_t *pool, size_t size); static void *ngx_palloc_large(ngx_pool_t *pool, size_t size); ngx_pool_t * ngx_create_pool(size_t size, ngx_log_t *log) { ngx_pool_t *p; p = ngx_memalign(NGX_POOL_ALIGNMENT, size, log); if (p == NULL) { return NULL; } p->d.last = (u_char *) p + sizeof(ngx_pool_t); p->d.end = (u_char *) p + size; p->d.next = NULL; p->d.failed = 0; size = size - sizeof(ngx_pool_t); p->max = (size < NGX_MAX_ALLOC_FROM_POOL) ? size : NGX_MAX_ALLOC_FROM_POOL; p->current = p; p->chain = NULL; p->large = NULL; p->cleanup = NULL; p->log = log; return p; } void ngx_destroy_pool(ngx_pool_t *pool) { ngx_pool_t *p, *n; ngx_pool_large_t *l; ngx_pool_cleanup_t *c; for (c = pool->cleanup; c; c = c->next) { if (c->handler) { ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, pool->log, 0, "run cleanup: %p", c); c->handler(c->data); } } #if (NGX_DEBUG) /* * we could allocate the pool->log from this pool * so we cannot use this log while free()ing the pool */ for (l = pool->large; l; l = l->next) { ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, pool->log, 0, "free: %p", l->alloc); } for (p = pool, n = pool->d.next; /* void */; p = n, n = n->d.next) { ngx_log_debug2(NGX_LOG_DEBUG_ALLOC, pool->log, 0, "free: %p, unused: %uz", p, p->d.end - p->d.last); if (n == NULL) { break; } } #endif for (l = pool->large; l; l = l->next) { if (l->alloc) { ngx_free(l->alloc); } } for (p = pool, n = pool->d.next; /* void */; p = n, n = n->d.next) { ngx_free(p); if (n == NULL) { break; } } } void ngx_reset_pool(ngx_pool_t *pool) { ngx_pool_t *p; ngx_pool_large_t *l; for (l = pool->large; l; l = l->next) { if (l->alloc) { ngx_free(l->alloc); } } for (p = pool; p; p = p->d.next) { p->d.last = (u_char *) p + sizeof(ngx_pool_t); p->d.failed = 0; } pool->current = pool; pool->chain = NULL; pool->large = NULL; } void * ngx_palloc(ngx_pool_t *pool, size_t size) { #if !(NGX_DEBUG_PALLOC) if (size <= pool->max) { return ngx_palloc_small(pool, size, 1); } #endif return ngx_palloc_large(pool, size); } void * ngx_pnalloc(ngx_pool_t *pool, size_t size) { #if !(NGX_DEBUG_PALLOC) if (size <= pool->max) { return ngx_palloc_small(pool, size, 0); } #endif return ngx_palloc_large(pool, size); } static ngx_inline void * ngx_palloc_small(ngx_pool_t *pool, size_t size, ngx_uint_t align) { u_char *m; ngx_pool_t *p; p = pool->current; do { m = p->d.last; if (align) { m = ngx_align_ptr(m, NGX_ALIGNMENT); } if ((size_t) (p->d.end - m) >= size) { p->d.last = m + size; return m; } p = p->d.next; } while (p); return ngx_palloc_block(pool, size); } static void * ngx_palloc_block(ngx_pool_t *pool, size_t size) { u_char *m; size_t psize; ngx_pool_t *p, *new; psize = (size_t) (pool->d.end - (u_char *) pool); m = ngx_memalign(NGX_POOL_ALIGNMENT, psize, pool->log); if (m == NULL) { return NULL; } new = (ngx_pool_t *) m; new->d.end = m + psize; new->d.next = NULL; new->d.failed = 0; m += sizeof(ngx_pool_data_t); m = ngx_align_ptr(m, NGX_ALIGNMENT); new->d.last = m + size; for (p = pool->current; p->d.next; p = p->d.next) { if (p->d.failed++ > 4) { pool->current = p->d.next; } } p->d.next = new; return m; } static void * ngx_palloc_large(ngx_pool_t *pool, size_t size) { void *p; ngx_uint_t n; ngx_pool_large_t *large; p = ngx_alloc(size, pool->log); if (p == NULL) { return NULL; } n = 0; for (large = pool->large; large; large = large->next) { if (large->alloc == NULL) { large->alloc = p; return p; } if (n++ > 3) { break; } } large = ngx_palloc_small(pool, sizeof(ngx_pool_large_t), 1); if (large == NULL) { ngx_free(p); return NULL; } large->alloc = p; large->next = pool->large; pool->large = large; return p; } void * ngx_pmemalign(ngx_pool_t *pool, size_t size, size_t alignment) { void *p; ngx_pool_large_t *large; p = ngx_memalign(alignment, size, pool->log); if (p == NULL) { return NULL; } large = ngx_palloc_small(pool, sizeof(ngx_pool_large_t), 1); if (large == NULL) { ngx_free(p); return NULL; } large->alloc = p; large->next = pool->large; pool->large = large; return p; } ngx_int_t ngx_pfree(ngx_pool_t *pool, void *p) { ngx_pool_large_t *l; for (l = pool->large; l; l = l->next) { if (p == l->alloc) { ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, pool->log, 0, "free: %p", l->alloc); ngx_free(l->alloc); l->alloc = NULL; return NGX_OK; } } return NGX_DECLINED; } void * ngx_pcalloc(ngx_pool_t *pool, size_t size) { void *p; p = ngx_palloc(pool, size); if (p) { ngx_memzero(p, size); } return p; } ngx_pool_cleanup_t * ngx_pool_cleanup_add(ngx_pool_t *p, size_t size) { ngx_pool_cleanup_t *c; c = ngx_palloc(p, sizeof(ngx_pool_cleanup_t)); if (c == NULL) { return NULL; } if (size) { c->data = ngx_palloc(p, size); if (c->data == NULL) { return NULL; } } else { c->data = NULL; } c->handler = NULL; c->next = p->cleanup; p->cleanup = c; ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, p->log, 0, "add cleanup: %p", c); return c; } void ngx_pool_run_cleanup_file(ngx_pool_t *p, ngx_fd_t fd) { ngx_pool_cleanup_t *c; ngx_pool_cleanup_file_t *cf; for (c = p->cleanup; c; c = c->next) { if (c->handler == ngx_pool_cleanup_file) { cf = c->data; if (cf->fd == fd) { c->handler(cf); c->handler = NULL; return; } } } } void ngx_pool_cleanup_file(void *data) { ngx_pool_cleanup_file_t *c = data; ngx_log_debug1(NGX_LOG_DEBUG_ALLOC, c->log, 0, "file cleanup: fd:%d", c->fd); if (ngx_close_file(c->fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, ngx_close_file_n " \"%s\" failed", c->name); } } void ngx_pool_delete_file(void *data) { ngx_pool_cleanup_file_t *c = data; ngx_err_t err; ngx_log_debug2(NGX_LOG_DEBUG_ALLOC, c->log, 0, "file cleanup: fd:%d %s", c->fd, c->name); if (ngx_delete_file(c->name) == NGX_FILE_ERROR) { err = ngx_errno; if (err != NGX_ENOENT) { ngx_log_error(NGX_LOG_CRIT, c->log, err, ngx_delete_file_n " \"%s\" failed", c->name); } } if (ngx_close_file(c->fd) == NGX_FILE_ERROR) { ngx_log_error(NGX_LOG_ALERT, c->log, ngx_errno, ngx_close_file_n " \"%s\" failed", c->name); } } #if 0 static void * ngx_get_cached_block(size_t size) { void *p; ngx_cached_block_slot_t *slot; if (ngx_cycle->cache == NULL) { return NULL; } slot = &ngx_cycle->cache[(size + ngx_pagesize - 1) / ngx_pagesize]; slot->tries++; if (slot->number) { p = slot->block; slot->block = slot->block->next; slot->number--; return p; } return NULL; } #endif