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[PATCH] Auth basic: Cache credentials if auth_basic_user_file is static

Toshihito Kikuchi
October 03, 2023 06:48PM
# HG changeset patch
# User Toshihito Kikuchi <leamovret@gmail.com>
# Date 1696359541 25200
# Tue Oct 03 11:59:01 2023 -0700
# Node ID e397ea6cfa85e85ae0865c5061397dc295fb7df1
# Parent 3db945fda515014d220151046d02f3960bcfca0a
Auth basic: Cache credentials if auth_basic_user_file is static.

In the current design, when auth_basic is on, every HTTP request triggers
file I/O (open, read, close) to the file specified in auth_basic_user_file.
Probably this is to allow auth_basic_user_file to contain variables.

If the value is just a static text, however, there is no reason to read the
same file every request in every worker process. It unnecessarily consumes
system resources.

With this patch, if auth_basic_user_file does not have any variables, we
cache its content in the location context at configuration time and use it
in all subsequent requests. If auth_basic_user_file contain variables, we keep
the original behavior.

diff --git a/src/http/modules/ngx_http_auth_basic_module.c b/src/http/modules/ngx_http_auth_basic_module.c
--- a/src/http/modules/ngx_http_auth_basic_module.c
+++ b/src/http/modules/ngx_http_auth_basic_module.c
@@ -15,11 +15,21 @@


typedef struct {
+ ngx_chain_t cache;
ngx_http_complex_value_t *realm;
ngx_http_complex_value_t *user_file;
} ngx_http_auth_basic_loc_conf_t;


+typedef struct {
+ off_t offset;
+ ngx_file_t file;
+ ngx_chain_t *chain;
+ ngx_http_request_t *r;
+ ngx_http_auth_basic_loc_conf_t *alcf;
+} ngx_http_auth_basic_file_ctx_t;
+
+
static ngx_int_t ngx_http_auth_basic_handler(ngx_http_request_t *r);
static ngx_int_t ngx_http_auth_basic_crypt_handler(ngx_http_request_t *r,
ngx_str_t *passwd, ngx_str_t *realm);
@@ -31,6 +41,14 @@ static char *ngx_http_auth_basic_merge_l
static ngx_int_t ngx_http_auth_basic_init(ngx_conf_t *cf);
static char *ngx_http_auth_basic_user_file(ngx_conf_t *cf, ngx_command_t *cmd,
void *conf);
+static ngx_int_t ngx_http_auth_basic_read_file(ngx_pool_t *pool,
+ ngx_str_t *filename, ngx_log_t *log, ngx_chain_t *chain_out);
+static ngx_int_t ngx_http_auth_basic_init_file_ctx(
+ ngx_http_auth_basic_file_ctx_t *ctx);
+static ssize_t ngx_http_auth_basic_read_file_ctx(
+ ngx_http_auth_basic_file_ctx_t *ctx, u_char *buf_out, size_t size);
+static void ngx_http_auth_basic_cleanup_file_ctx(
+ ngx_http_auth_basic_file_ctx_t *ctx);


static ngx_command_t ngx_http_auth_basic_commands[] = {
@@ -89,14 +107,11 @@ ngx_module_t ngx_http_auth_basic_module
static ngx_int_t
ngx_http_auth_basic_handler(ngx_http_request_t *r)
{
- off_t offset;
ssize_t n;
- ngx_fd_t fd;
ngx_int_t rc;
- ngx_err_t err;
- ngx_str_t pwd, realm, user_file;
- ngx_uint_t i, level, login, left, passwd;
- ngx_file_t file;
+ ngx_str_t pwd, realm;
+ ngx_uint_t i, login, left, passwd;
+ ngx_http_auth_basic_file_ctx_t file_ctx;
ngx_http_auth_basic_loc_conf_t *alcf;
u_char buf[NGX_HTTP_AUTH_BUF_SIZE];
enum {
@@ -133,47 +148,23 @@ ngx_http_auth_basic_handler(ngx_http_req
return NGX_HTTP_INTERNAL_SERVER_ERROR;
}

- if (ngx_http_complex_value(r, alcf->user_file, &user_file) != NGX_OK) {
- return NGX_ERROR;
- }
-
- fd = ngx_open_file(user_file.data, NGX_FILE_RDONLY, NGX_FILE_OPEN, 0);
-
- if (fd == NGX_INVALID_FILE) {
- err = ngx_errno;
-
- if (err == NGX_ENOENT) {
- level = NGX_LOG_ERR;
- rc = NGX_HTTP_FORBIDDEN;
-
- } else {
- level = NGX_LOG_CRIT;
- rc = NGX_HTTP_INTERNAL_SERVER_ERROR;
- }
-
- ngx_log_error(level, r->connection->log, err,
- ngx_open_file_n " \"%s\" failed", user_file.data);
-
+ file_ctx.alcf = alcf;
+ file_ctx.r = r;
+ rc = ngx_http_auth_basic_init_file_ctx(&file_ctx);
+ if (rc != NGX_OK) {
return rc;
}

- ngx_memzero(&file, sizeof(ngx_file_t));
-
- file.fd = fd;
- file.name = user_file;
- file.log = r->connection->log;
-
state = sw_login;
passwd = 0;
login = 0;
left = 0;
- offset = 0;

for ( ;; ) {
i = left;

- n = ngx_read_file(&file, buf + left, NGX_HTTP_AUTH_BUF_SIZE - left,
- offset);
+ n = ngx_http_auth_basic_read_file_ctx(&file_ctx, buf + left,
+ NGX_HTTP_AUTH_BUF_SIZE - left);

if (n == NGX_ERROR) {
rc = NGX_HTTP_INTERNAL_SERVER_ERROR;
@@ -245,8 +236,6 @@ ngx_http_auth_basic_handler(ngx_http_req
} else {
left = 0;
}
-
- offset += n;
}

if (state == sw_passwd) {
@@ -264,16 +253,13 @@ ngx_http_auth_basic_handler(ngx_http_req

ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
"user \"%V\" was not found in \"%s\"",
- &r->headers_in.user, user_file.data);
+ &r->headers_in.user, &file_ctx.file.name.data);

rc = ngx_http_auth_basic_set_realm(r, &realm);

cleanup:

- if (ngx_close_file(file.fd) == NGX_FILE_ERROR) {
- ngx_log_error(NGX_LOG_ALERT, r->connection->log, ngx_errno,
- ngx_close_file_n " \"%s\" failed", user_file.data);
- }
+ ngx_http_auth_basic_cleanup_file_ctx(&file_ctx);

ngx_explicit_memzero(buf, NGX_HTTP_AUTH_BUF_SIZE);

@@ -374,6 +360,19 @@ ngx_http_auth_basic_merge_loc_conf(ngx_c
ngx_conf_merge_ptr_value(conf->realm, prev->realm, NULL);
ngx_conf_merge_ptr_value(conf->user_file, prev->user_file, NULL);

+ if (conf->user_file != NULL && conf->user_file->lengths == NULL) {
+
+ /*
+ * If the given expression is a static text, we read the file at
+ * configuration time.
+ */
+
+ if (ngx_http_auth_basic_read_file(cf->pool, &conf->user_file->value,
+ cf->log, &conf->cache) != NGX_OK) {
+ return NGX_CONF_ERROR;
+ }
+ }
+
return NGX_CONF_OK;
}

@@ -430,3 +429,207 @@ ngx_http_auth_basic_user_file(ngx_conf_t

return NGX_CONF_OK;
}
+
+
+static ngx_int_t
+ngx_http_auth_basic_read_file(ngx_pool_t *pool, ngx_str_t *filename,
+ ngx_log_t *log, ngx_chain_t *chain_out)
+{
+ off_t offset;
+ ssize_t n;
+ ngx_fd_t fd;
+ ngx_buf_t *p;
+ ngx_int_t rc;
+ ngx_file_t file;
+ ngx_chain_t *cl;
+ u_char buf[NGX_HTTP_AUTH_BUF_SIZE];
+
+ if (chain_out == NULL
+ || chain_out->buf != NULL
+ || chain_out->next != NULL) {
+ ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
+ "ngx_http_auth_basic_read_file() accepts only an empty"
+ " chain.");
+ return NGX_ERROR;
+ }
+
+ fd = ngx_open_file(filename->data, NGX_FILE_RDONLY, NGX_FILE_OPEN, 0);
+ if (fd == NGX_INVALID_FILE) {
+ ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
+ ngx_open_file_n " \"%V\" failed", filename);
+ return NGX_ENOENT;
+ }
+
+ ngx_memzero(&file, sizeof(ngx_file_t));
+ file.fd = fd;
+ file.name = *filename;
+ file.log = log;
+
+ rc = NGX_OK;
+
+ for (offset = 0; /* void */ ; offset += n) {
+ n = ngx_read_file(&file, buf, NGX_HTTP_AUTH_BUF_SIZE, offset);
+ if (n == 0) {
+ break;
+
+ } else if (n == NGX_ERROR) {
+ rc = NGX_ERROR;
+ break;
+ }
+
+ p = ngx_create_temp_buf(pool, n);
+ if (p == NULL) {
+ rc = NGX_ENOMEM;
+ ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
+ "Cannot allocate a buffer");
+ break;
+ }
+
+ ngx_memcpy(p->start, buf, n);
+
+ if (chain_out->buf == NULL) {
+
+ /* First chain is provided by the caller. No allocation needed. */
+
+ chain_out->buf = p;
+
+ } else {
+ cl = ngx_alloc_chain_link(pool);
+ if (cl == NULL) {
+ rc = NGX_ENOMEM;
+ ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
+ "Cannot allocate a chain");
+ break;
+ }
+
+ cl->buf = p;
+ chain_out->next = cl;
+ chain_out = cl;
+ }
+ }
+
+ if (ngx_close_file(fd) == NGX_FILE_ERROR) {
+ ngx_log_error(NGX_LOG_ALERT, log, ngx_errno,
+ ngx_close_file_n " \"%V\" failed", filename);
+ }
+
+ return rc;
+}
+
+
+static ngx_int_t
+ngx_http_auth_basic_init_file_ctx(ngx_http_auth_basic_file_ctx_t *ctx)
+{
+ ngx_fd_t fd;
+ ngx_err_t err;
+ ngx_int_t rc;
+ ngx_str_t user_file;
+ ngx_uint_t level;
+ ngx_http_request_t *r;
+ ngx_http_auth_basic_loc_conf_t *alcf;
+
+ r = ctx->r;
+ alcf = ctx->alcf;
+
+ ngx_memzero(&ctx->file, sizeof(ngx_file_t));
+ ctx->chain = NULL;
+ ctx->offset = 0;
+
+ if (alcf->user_file->lengths == NULL) {
+ ctx->chain = &alcf->cache;
+ ctx->file.name = alcf->user_file->value;
+ return NGX_OK;
+ }
+
+ if (ngx_http_complex_value(r, alcf->user_file, &user_file) != NGX_OK) {
+ return NGX_ERROR;
+ }
+
+ fd = ngx_open_file(user_file.data, NGX_FILE_RDONLY, NGX_FILE_OPEN, 0);
+
+ if (fd == NGX_INVALID_FILE) {
+ err = ngx_errno;
+
+ if (err == NGX_ENOENT) {
+ level = NGX_LOG_ERR;
+ rc = NGX_HTTP_FORBIDDEN;
+
+ } else {
+ level = NGX_LOG_CRIT;
+ rc = NGX_HTTP_INTERNAL_SERVER_ERROR;
+ }
+
+ ngx_log_error(level, r->connection->log, err,
+ ngx_open_file_n " \"%s\" failed", user_file.data);
+
+ return rc;
+ }
+
+ ctx->file.fd = fd;
+ ctx->file.name = user_file;
+ ctx->file.log = r->connection->log;
+
+ return NGX_OK;
+}
+
+
+static ssize_t
+ngx_http_auth_basic_read_file_ctx(ngx_http_auth_basic_file_ctx_t *ctx,
+ u_char *buf_out, size_t size)
+{
+ off_t offset;
+ size_t remaining;
+ u_char *p;
+ ssize_t n;
+ ngx_buf_t *buf;
+ ngx_chain_t *cl;
+
+ if (!ctx->alcf->user_file->lengths) {
+ offset = ctx->offset;
+ p = buf_out;
+ n = 0;
+
+ for (cl = ctx->chain; cl; cl = cl->next) {
+ buf = cl->buf;
+ remaining = buf->end - buf->start - offset;
+ if (size <= remaining) {
+ ngx_memcpy(p, buf->start, size);
+ n += size;
+ offset += size;
+ break;
+ }
+
+ ngx_memcpy(p, buf->start, remaining);
+ n += remaining;
+ p += remaining;
+ size -= remaining;
+ offset = 0;
+ }
+
+ ctx->chain = cl;
+ ctx->offset = offset;
+ return n;
+ }
+
+ n = ngx_read_file(&ctx->file, buf_out, size, ctx->offset);
+ if (n == NGX_ERROR) {
+ return NGX_ERROR;
+ }
+
+ ctx->offset += n;
+ return n;
+}
+
+
+static void
+ngx_http_auth_basic_cleanup_file_ctx(ngx_http_auth_basic_file_ctx_t *ctx)
+{
+ if (ctx->alcf->user_file->lengths == NULL) {
+ return;
+ }
+
+ if (ngx_close_file(ctx->file.fd) == NGX_FILE_ERROR) {
+ ngx_log_error(NGX_LOG_ALERT, ctx->r->connection->log, ngx_errno,
+ ngx_close_file_n " \"%s\" failed", ctx->file.name.data);
+ }
+}
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Subject Author Views Posted

[PATCH] Auth basic: Cache credentials if auth_basic_user_file is static

Toshihito Kikuchi 249 October 03, 2023 06:48PM

Re: [PATCH] Auth basic: Cache credentials if auth_basic_user_file is static

Maxim Dounin 67 October 03, 2023 09:04PM

Re: [PATCH] Auth basic: Cache credentials if auth_basic_user_file is static

Toshihito Kikuchi 71 October 04, 2023 05:34PM



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