Mercurial > hg > nginx
view src/core/ngx_hash.c @ 7094:c7d4017c8876
Secure link: fixed stack buffer overflow.
When secure link checksum has length of 23 or 24 bytes, decoded base64 value
could occupy 17 or 18 bytes which is more than 16 bytes previously allocated
for it on stack. The buffer overflow does not have any security implications
since only one local variable was corrupted and this variable was not used in
this case.
The fix is to increase buffer size up to 18 bytes. Useless buffer size
initialization is removed as well.
author | Roman Arutyunyan <arut@nginx.com> |
---|---|
date | Tue, 22 Aug 2017 21:22:59 +0300 |
parents | 7fc16ff7ddc4 |
children | c3f60d618c17 |
line wrap: on
line source
/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> void * ngx_hash_find(ngx_hash_t *hash, ngx_uint_t key, u_char *name, size_t len) { ngx_uint_t i; ngx_hash_elt_t *elt; #if 0 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0, "hf:\"%*s\"", len, name); #endif elt = hash->buckets[key % hash->size]; if (elt == NULL) { return NULL; } while (elt->value) { if (len != (size_t) elt->len) { goto next; } for (i = 0; i < len; i++) { if (name[i] != elt->name[i]) { goto next; } } return elt->value; next: elt = (ngx_hash_elt_t *) ngx_align_ptr(&elt->name[0] + elt->len, sizeof(void *)); continue; } return NULL; } void * ngx_hash_find_wc_head(ngx_hash_wildcard_t *hwc, u_char *name, size_t len) { void *value; ngx_uint_t i, n, key; #if 0 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0, "wch:\"%*s\"", len, name); #endif n = len; while (n) { if (name[n - 1] == '.') { break; } n--; } key = 0; for (i = n; i < len; i++) { key = ngx_hash(key, name[i]); } #if 0 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0, "key:\"%ui\"", key); #endif value = ngx_hash_find(&hwc->hash, key, &name[n], len - n); #if 0 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0, "value:\"%p\"", value); #endif if (value) { /* * the 2 low bits of value have the special meaning: * 00 - value is data pointer for both "example.com" * and "*.example.com"; * 01 - value is data pointer for "*.example.com" only; * 10 - value is pointer to wildcard hash allowing * both "example.com" and "*.example.com"; * 11 - value is pointer to wildcard hash allowing * "*.example.com" only. */ if ((uintptr_t) value & 2) { if (n == 0) { /* "example.com" */ if ((uintptr_t) value & 1) { return NULL; } hwc = (ngx_hash_wildcard_t *) ((uintptr_t) value & (uintptr_t) ~3); return hwc->value; } hwc = (ngx_hash_wildcard_t *) ((uintptr_t) value & (uintptr_t) ~3); value = ngx_hash_find_wc_head(hwc, name, n - 1); if (value) { return value; } return hwc->value; } if ((uintptr_t) value & 1) { if (n == 0) { /* "example.com" */ return NULL; } return (void *) ((uintptr_t) value & (uintptr_t) ~3); } return value; } return hwc->value; } void * ngx_hash_find_wc_tail(ngx_hash_wildcard_t *hwc, u_char *name, size_t len) { void *value; ngx_uint_t i, key; #if 0 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0, "wct:\"%*s\"", len, name); #endif key = 0; for (i = 0; i < len; i++) { if (name[i] == '.') { break; } key = ngx_hash(key, name[i]); } if (i == len) { return NULL; } #if 0 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0, "key:\"%ui\"", key); #endif value = ngx_hash_find(&hwc->hash, key, name, i); #if 0 ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0, "value:\"%p\"", value); #endif if (value) { /* * the 2 low bits of value have the special meaning: * 00 - value is data pointer; * 11 - value is pointer to wildcard hash allowing "example.*". */ if ((uintptr_t) value & 2) { i++; hwc = (ngx_hash_wildcard_t *) ((uintptr_t) value & (uintptr_t) ~3); value = ngx_hash_find_wc_tail(hwc, &name[i], len - i); if (value) { return value; } return hwc->value; } return value; } return hwc->value; } void * ngx_hash_find_combined(ngx_hash_combined_t *hash, ngx_uint_t key, u_char *name, size_t len) { void *value; if (hash->hash.buckets) { value = ngx_hash_find(&hash->hash, key, name, len); if (value) { return value; } } if (len == 0) { return NULL; } if (hash->wc_head && hash->wc_head->hash.buckets) { value = ngx_hash_find_wc_head(hash->wc_head, name, len); if (value) { return value; } } if (hash->wc_tail && hash->wc_tail->hash.buckets) { value = ngx_hash_find_wc_tail(hash->wc_tail, name, len); if (value) { return value; } } return NULL; } #define NGX_HASH_ELT_SIZE(name) \ (sizeof(void *) + ngx_align((name)->key.len + 2, sizeof(void *))) ngx_int_t ngx_hash_init(ngx_hash_init_t *hinit, ngx_hash_key_t *names, ngx_uint_t nelts) { u_char *elts; size_t len; u_short *test; ngx_uint_t i, n, key, size, start, bucket_size; ngx_hash_elt_t *elt, **buckets; if (hinit->max_size == 0) { ngx_log_error(NGX_LOG_EMERG, hinit->pool->log, 0, "could not build %s, you should " "increase %s_max_size: %i", hinit->name, hinit->name, hinit->max_size); return NGX_ERROR; } for (n = 0; n < nelts; n++) { if (hinit->bucket_size < NGX_HASH_ELT_SIZE(&names[n]) + sizeof(void *)) { ngx_log_error(NGX_LOG_EMERG, hinit->pool->log, 0, "could not build %s, you should " "increase %s_bucket_size: %i", hinit->name, hinit->name, hinit->bucket_size); return NGX_ERROR; } } test = ngx_alloc(hinit->max_size * sizeof(u_short), hinit->pool->log); if (test == NULL) { return NGX_ERROR; } bucket_size = hinit->bucket_size - sizeof(void *); start = nelts / (bucket_size / (2 * sizeof(void *))); start = start ? start : 1; if (hinit->max_size > 10000 && nelts && hinit->max_size / nelts < 100) { start = hinit->max_size - 1000; } for (size = start; size <= hinit->max_size; size++) { ngx_memzero(test, size * sizeof(u_short)); for (n = 0; n < nelts; n++) { if (names[n].key.data == NULL) { continue; } key = names[n].key_hash % size; test[key] = (u_short) (test[key] + NGX_HASH_ELT_SIZE(&names[n])); #if 0 ngx_log_error(NGX_LOG_ALERT, hinit->pool->log, 0, "%ui: %ui %ui \"%V\"", size, key, test[key], &names[n].key); #endif if (test[key] > (u_short) bucket_size) { goto next; } } goto found; next: continue; } size = hinit->max_size; ngx_log_error(NGX_LOG_WARN, hinit->pool->log, 0, "could not build optimal %s, you should increase " "either %s_max_size: %i or %s_bucket_size: %i; " "ignoring %s_bucket_size", hinit->name, hinit->name, hinit->max_size, hinit->name, hinit->bucket_size, hinit->name); found: for (i = 0; i < size; i++) { test[i] = sizeof(void *); } for (n = 0; n < nelts; n++) { if (names[n].key.data == NULL) { continue; } key = names[n].key_hash % size; test[key] = (u_short) (test[key] + NGX_HASH_ELT_SIZE(&names[n])); } len = 0; for (i = 0; i < size; i++) { if (test[i] == sizeof(void *)) { continue; } test[i] = (u_short) (ngx_align(test[i], ngx_cacheline_size)); len += test[i]; } if (hinit->hash == NULL) { hinit->hash = ngx_pcalloc(hinit->pool, sizeof(ngx_hash_wildcard_t) + size * sizeof(ngx_hash_elt_t *)); if (hinit->hash == NULL) { ngx_free(test); return NGX_ERROR; } buckets = (ngx_hash_elt_t **) ((u_char *) hinit->hash + sizeof(ngx_hash_wildcard_t)); } else { buckets = ngx_pcalloc(hinit->pool, size * sizeof(ngx_hash_elt_t *)); if (buckets == NULL) { ngx_free(test); return NGX_ERROR; } } elts = ngx_palloc(hinit->pool, len + ngx_cacheline_size); if (elts == NULL) { ngx_free(test); return NGX_ERROR; } elts = ngx_align_ptr(elts, ngx_cacheline_size); for (i = 0; i < size; i++) { if (test[i] == sizeof(void *)) { continue; } buckets[i] = (ngx_hash_elt_t *) elts; elts += test[i]; } for (i = 0; i < size; i++) { test[i] = 0; } for (n = 0; n < nelts; n++) { if (names[n].key.data == NULL) { continue; } key = names[n].key_hash % size; elt = (ngx_hash_elt_t *) ((u_char *) buckets[key] + test[key]); elt->value = names[n].value; elt->len = (u_short) names[n].key.len; ngx_strlow(elt->name, names[n].key.data, names[n].key.len); test[key] = (u_short) (test[key] + NGX_HASH_ELT_SIZE(&names[n])); } for (i = 0; i < size; i++) { if (buckets[i] == NULL) { continue; } elt = (ngx_hash_elt_t *) ((u_char *) buckets[i] + test[i]); elt->value = NULL; } ngx_free(test); hinit->hash->buckets = buckets; hinit->hash->size = size; #if 0 for (i = 0; i < size; i++) { ngx_str_t val; ngx_uint_t key; elt = buckets[i]; if (elt == NULL) { ngx_log_error(NGX_LOG_ALERT, hinit->pool->log, 0, "%ui: NULL", i); continue; } while (elt->value) { val.len = elt->len; val.data = &elt->name[0]; key = hinit->key(val.data, val.len); ngx_log_error(NGX_LOG_ALERT, hinit->pool->log, 0, "%ui: %p \"%V\" %ui", i, elt, &val, key); elt = (ngx_hash_elt_t *) ngx_align_ptr(&elt->name[0] + elt->len, sizeof(void *)); } } #endif return NGX_OK; } ngx_int_t ngx_hash_wildcard_init(ngx_hash_init_t *hinit, ngx_hash_key_t *names, ngx_uint_t nelts) { size_t len, dot_len; ngx_uint_t i, n, dot; ngx_array_t curr_names, next_names; ngx_hash_key_t *name, *next_name; ngx_hash_init_t h; ngx_hash_wildcard_t *wdc; if (ngx_array_init(&curr_names, hinit->temp_pool, nelts, sizeof(ngx_hash_key_t)) != NGX_OK) { return NGX_ERROR; } if (ngx_array_init(&next_names, hinit->temp_pool, nelts, sizeof(ngx_hash_key_t)) != NGX_OK) { return NGX_ERROR; } for (n = 0; n < nelts; n = i) { #if 0 ngx_log_error(NGX_LOG_ALERT, hinit->pool->log, 0, "wc0: \"%V\"", &names[n].key); #endif dot = 0; for (len = 0; len < names[n].key.len; len++) { if (names[n].key.data[len] == '.') { dot = 1; break; } } name = ngx_array_push(&curr_names); if (name == NULL) { return NGX_ERROR; } name->key.len = len; name->key.data = names[n].key.data; name->key_hash = hinit->key(name->key.data, name->key.len); name->value = names[n].value; #if 0 ngx_log_error(NGX_LOG_ALERT, hinit->pool->log, 0, "wc1: \"%V\" %ui", &name->key, dot); #endif dot_len = len + 1; if (dot) { len++; } next_names.nelts = 0; if (names[n].key.len != len) { next_name = ngx_array_push(&next_names); if (next_name == NULL) { return NGX_ERROR; } next_name->key.len = names[n].key.len - len; next_name->key.data = names[n].key.data + len; next_name->key_hash = 0; next_name->value = names[n].value; #if 0 ngx_log_error(NGX_LOG_ALERT, hinit->pool->log, 0, "wc2: \"%V\"", &next_name->key); #endif } for (i = n + 1; i < nelts; i++) { if (ngx_strncmp(names[n].key.data, names[i].key.data, len) != 0) { break; } if (!dot && names[i].key.len > len && names[i].key.data[len] != '.') { break; } next_name = ngx_array_push(&next_names); if (next_name == NULL) { return NGX_ERROR; } next_name->key.len = names[i].key.len - dot_len; next_name->key.data = names[i].key.data + dot_len; next_name->key_hash = 0; next_name->value = names[i].value; #if 0 ngx_log_error(NGX_LOG_ALERT, hinit->pool->log, 0, "wc3: \"%V\"", &next_name->key); #endif } if (next_names.nelts) { h = *hinit; h.hash = NULL; if (ngx_hash_wildcard_init(&h, (ngx_hash_key_t *) next_names.elts, next_names.nelts) != NGX_OK) { return NGX_ERROR; } wdc = (ngx_hash_wildcard_t *) h.hash; if (names[n].key.len == len) { wdc->value = names[n].value; } name->value = (void *) ((uintptr_t) wdc | (dot ? 3 : 2)); } else if (dot) { name->value = (void *) ((uintptr_t) name->value | 1); } } if (ngx_hash_init(hinit, (ngx_hash_key_t *) curr_names.elts, curr_names.nelts) != NGX_OK) { return NGX_ERROR; } return NGX_OK; } ngx_uint_t ngx_hash_key(u_char *data, size_t len) { ngx_uint_t i, key; key = 0; for (i = 0; i < len; i++) { key = ngx_hash(key, data[i]); } return key; } ngx_uint_t ngx_hash_key_lc(u_char *data, size_t len) { ngx_uint_t i, key; key = 0; for (i = 0; i < len; i++) { key = ngx_hash(key, ngx_tolower(data[i])); } return key; } ngx_uint_t ngx_hash_strlow(u_char *dst, u_char *src, size_t n) { ngx_uint_t key; key = 0; while (n--) { *dst = ngx_tolower(*src); key = ngx_hash(key, *dst); dst++; src++; } return key; } ngx_int_t ngx_hash_keys_array_init(ngx_hash_keys_arrays_t *ha, ngx_uint_t type) { ngx_uint_t asize; if (type == NGX_HASH_SMALL) { asize = 4; ha->hsize = 107; } else { asize = NGX_HASH_LARGE_ASIZE; ha->hsize = NGX_HASH_LARGE_HSIZE; } if (ngx_array_init(&ha->keys, ha->temp_pool, asize, sizeof(ngx_hash_key_t)) != NGX_OK) { return NGX_ERROR; } if (ngx_array_init(&ha->dns_wc_head, ha->temp_pool, asize, sizeof(ngx_hash_key_t)) != NGX_OK) { return NGX_ERROR; } if (ngx_array_init(&ha->dns_wc_tail, ha->temp_pool, asize, sizeof(ngx_hash_key_t)) != NGX_OK) { return NGX_ERROR; } ha->keys_hash = ngx_pcalloc(ha->temp_pool, sizeof(ngx_array_t) * ha->hsize); if (ha->keys_hash == NULL) { return NGX_ERROR; } ha->dns_wc_head_hash = ngx_pcalloc(ha->temp_pool, sizeof(ngx_array_t) * ha->hsize); if (ha->dns_wc_head_hash == NULL) { return NGX_ERROR; } ha->dns_wc_tail_hash = ngx_pcalloc(ha->temp_pool, sizeof(ngx_array_t) * ha->hsize); if (ha->dns_wc_tail_hash == NULL) { return NGX_ERROR; } return NGX_OK; } ngx_int_t ngx_hash_add_key(ngx_hash_keys_arrays_t *ha, ngx_str_t *key, void *value, ngx_uint_t flags) { size_t len; u_char *p; ngx_str_t *name; ngx_uint_t i, k, n, skip, last; ngx_array_t *keys, *hwc; ngx_hash_key_t *hk; last = key->len; if (flags & NGX_HASH_WILDCARD_KEY) { /* * supported wildcards: * "*.example.com", ".example.com", and "www.example.*" */ n = 0; for (i = 0; i < key->len; i++) { if (key->data[i] == '*') { if (++n > 1) { return NGX_DECLINED; } } if (key->data[i] == '.' && key->data[i + 1] == '.') { return NGX_DECLINED; } if (key->data[i] == '\0') { return NGX_DECLINED; } } if (key->len > 1 && key->data[0] == '.') { skip = 1; goto wildcard; } if (key->len > 2) { if (key->data[0] == '*' && key->data[1] == '.') { skip = 2; goto wildcard; } if (key->data[i - 2] == '.' && key->data[i - 1] == '*') { skip = 0; last -= 2; goto wildcard; } } if (n) { return NGX_DECLINED; } } /* exact hash */ k = 0; for (i = 0; i < last; i++) { if (!(flags & NGX_HASH_READONLY_KEY)) { key->data[i] = ngx_tolower(key->data[i]); } k = ngx_hash(k, key->data[i]); } k %= ha->hsize; /* check conflicts in exact hash */ name = ha->keys_hash[k].elts; if (name) { for (i = 0; i < ha->keys_hash[k].nelts; i++) { if (last != name[i].len) { continue; } if (ngx_strncmp(key->data, name[i].data, last) == 0) { return NGX_BUSY; } } } else { if (ngx_array_init(&ha->keys_hash[k], ha->temp_pool, 4, sizeof(ngx_str_t)) != NGX_OK) { return NGX_ERROR; } } name = ngx_array_push(&ha->keys_hash[k]); if (name == NULL) { return NGX_ERROR; } *name = *key; hk = ngx_array_push(&ha->keys); if (hk == NULL) { return NGX_ERROR; } hk->key = *key; hk->key_hash = ngx_hash_key(key->data, last); hk->value = value; return NGX_OK; wildcard: /* wildcard hash */ k = ngx_hash_strlow(&key->data[skip], &key->data[skip], last - skip); k %= ha->hsize; if (skip == 1) { /* check conflicts in exact hash for ".example.com" */ name = ha->keys_hash[k].elts; if (name) { len = last - skip; for (i = 0; i < ha->keys_hash[k].nelts; i++) { if (len != name[i].len) { continue; } if (ngx_strncmp(&key->data[1], name[i].data, len) == 0) { return NGX_BUSY; } } } else { if (ngx_array_init(&ha->keys_hash[k], ha->temp_pool, 4, sizeof(ngx_str_t)) != NGX_OK) { return NGX_ERROR; } } name = ngx_array_push(&ha->keys_hash[k]); if (name == NULL) { return NGX_ERROR; } name->len = last - 1; name->data = ngx_pnalloc(ha->temp_pool, name->len); if (name->data == NULL) { return NGX_ERROR; } ngx_memcpy(name->data, &key->data[1], name->len); } if (skip) { /* * convert "*.example.com" to "com.example.\0" * and ".example.com" to "com.example\0" */ p = ngx_pnalloc(ha->temp_pool, last); if (p == NULL) { return NGX_ERROR; } len = 0; n = 0; for (i = last - 1; i; i--) { if (key->data[i] == '.') { ngx_memcpy(&p[n], &key->data[i + 1], len); n += len; p[n++] = '.'; len = 0; continue; } len++; } if (len) { ngx_memcpy(&p[n], &key->data[1], len); n += len; } p[n] = '\0'; hwc = &ha->dns_wc_head; keys = &ha->dns_wc_head_hash[k]; } else { /* convert "www.example.*" to "www.example\0" */ last++; p = ngx_pnalloc(ha->temp_pool, last); if (p == NULL) { return NGX_ERROR; } ngx_cpystrn(p, key->data, last); hwc = &ha->dns_wc_tail; keys = &ha->dns_wc_tail_hash[k]; } /* check conflicts in wildcard hash */ name = keys->elts; if (name) { len = last - skip; for (i = 0; i < keys->nelts; i++) { if (len != name[i].len) { continue; } if (ngx_strncmp(key->data + skip, name[i].data, len) == 0) { return NGX_BUSY; } } } else { if (ngx_array_init(keys, ha->temp_pool, 4, sizeof(ngx_str_t)) != NGX_OK) { return NGX_ERROR; } } name = ngx_array_push(keys); if (name == NULL) { return NGX_ERROR; } name->len = last - skip; name->data = ngx_pnalloc(ha->temp_pool, name->len); if (name->data == NULL) { return NGX_ERROR; } ngx_memcpy(name->data, key->data + skip, name->len); /* add to wildcard hash */ hk = ngx_array_push(hwc); if (hk == NULL) { return NGX_ERROR; } hk->key.len = last - 1; hk->key.data = p; hk->key_hash = 0; hk->value = value; return NGX_OK; }