Mercurial > hg > nginx
changeset 9188:b05c622715fa
HTTP: uniform checks in ngx_http_alloc_large_header_buffer().
If URI is not fully parsed yet, some pointers are not set. As a result,
the calculation of "new + (ptr - old)" expression is flawed.
According to C11, 6.5.6 Additive operators, p.9:
: When two pointers are subtracted, both shall point to elements
: of the same array object, or one past the last element of the
: array object
Since "ptr" is not set, subtraction leads to undefined behaviour, because
"ptr" and "old" are not in the same buffer (i.e. array objects).
Prodded by GCC undefined behaviour sanitizer.
author | Vladimir Khomutov <vl@wbsrv.ru> |
---|---|
date | Wed, 29 Nov 2023 11:13:05 +0300 |
parents | dacad3a9c7b8 |
children | fcec773dd249 |
files | src/http/ngx_http_request.c |
diffstat | 1 files changed, 26 insertions(+), 8 deletions(-) [+] |
line wrap: on
line diff
--- a/src/http/ngx_http_request.c +++ b/src/http/ngx_http_request.c @@ -1718,14 +1718,23 @@ ngx_http_alloc_large_header_buffer(ngx_h r->request_end = new + (r->request_end - old); } - r->method_end = new + (r->method_end - old); - - r->uri_start = new + (r->uri_start - old); - r->uri_end = new + (r->uri_end - old); + if (r->method_end) { + r->method_end = new + (r->method_end - old); + } + + if (r->uri_start) { + r->uri_start = new + (r->uri_start - old); + } + + if (r->uri_end) { + r->uri_end = new + (r->uri_end - old); + } if (r->schema_start) { r->schema_start = new + (r->schema_start - old); - r->schema_end = new + (r->schema_end - old); + if (r->schema_end) { + r->schema_end = new + (r->schema_end - old); + } } if (r->host_start) { @@ -1749,9 +1758,18 @@ ngx_http_alloc_large_header_buffer(ngx_h } else { r->header_name_start = new; - r->header_name_end = new + (r->header_name_end - old); - r->header_start = new + (r->header_start - old); - r->header_end = new + (r->header_end - old); + + if (r->header_name_end) { + r->header_name_end = new + (r->header_name_end - old); + } + + if (r->header_start) { + r->header_start = new + (r->header_start - old); + } + + if (r->header_end) { + r->header_end = new + (r->header_end - old); + } } r->header_in = b;