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[Openvpn-devel,v2,1/2] In init_ssl, open the correct CRL path pre-chroot

Message ID E1lVzi7-00011Y-2c@sfs-ml-2.v29.lw.sourceforge.com
State Changes Requested
Delegated to: Antonio Quartulli
Headers show
Series CRL reloading and chroot with mbedtls | expand

Commit Message

Maximilian Fillinger April 12, 2021, 6:45 a.m. UTC 
When using the chroot option, the init_ssl function can be called before
entering the chroot or, when OpenVPN receives a SIGHUP, afterwards. This
commit ensures that OpenVPN tries to open the correct path for the CRL
file in either situations.

This commit does not address key and certificate files. For these, the
--persist-key option should be used.

Signed-off-by: Max Fillinger <maximilian.fillinger@foxcrypto.com>
---
 src/openvpn/init.c    |  3 ++-
 src/openvpn/misc.c    | 11 +++++++++++
 src/openvpn/misc.h    |  7 +++++++
 src/openvpn/options.c |  8 +-------
 src/openvpn/ssl.c     | 20 ++++++++++++++++++--
 src/openvpn/ssl.h     |  2 +-
 6 files changed, 40 insertions(+), 11 deletions(-)
diff mbox series

Patch

diff --git a/src/openvpn/init.c b/src/openvpn/init.c
index 28d183aa..ba38e548 100644
--- a/src/openvpn/init.c
+++ b/src/openvpn/init.c
@@ -2702,7 +2702,8 @@  do_init_crypto_tls_c1(struct context *c)
          * Initialize the OpenSSL library's global
          * SSL context.
          */
-        init_ssl(options, &(c->c1.ks.ssl_ctx));
+        bool in_chroot = (c->c0 != NULL) ? c->c0->uid_gid_chroot_set : false;
+        init_ssl(options, &(c->c1.ks.ssl_ctx), in_chroot);
         if (!tls_ctx_initialised(&c->c1.ks.ssl_ctx))
         {
             switch (auth_retry_get())
diff --git a/src/openvpn/misc.c b/src/openvpn/misc.c
index feaefb3b..a64803a7 100644
--- a/src/openvpn/misc.c
+++ b/src/openvpn/misc.c
@@ -767,3 +767,14 @@  get_num_elements(const char *string, char delimiter)
 
     return element_count;
 }
+
+struct buffer
+prepend_chroot(const char *chroot_dir, const char *path, struct gc_arena *gc)
+{
+    size_t len = strlen(chroot_dir) + strlen(PATH_SEPARATOR_STR) + strlen(path) + 1;
+    struct buffer combined_path = alloc_buf_gc(len, gc);
+    buf_printf(&combined_path, "%s%s%s", chroot_dir, PATH_SEPARATOR_STR, path);
+    ASSERT(combined_path.len > 0);
+
+    return combined_path;
+}
diff --git a/src/openvpn/misc.h b/src/openvpn/misc.h
index 9b018eb5..9f352754 100644
--- a/src/openvpn/misc.h
+++ b/src/openvpn/misc.h
@@ -190,4 +190,11 @@  void output_peer_info_env(struct env_set *es, const char *peer_info);
 int
 get_num_elements(const char *string, char delimiter);
 
+/**
+ * Prepend the chroot directory to a path. Used when we need to access
+ * a file in the chroot directory before we have chroot-ed.
+ */
+struct buffer
+prepend_chroot(const char *chroot_dir, const char *path, struct gc_arena *gc);
+
 #endif /* ifndef MISC_H */
diff --git a/src/openvpn/options.c b/src/openvpn/options.c
index 9e61b1e0..d6ba2938 100644
--- a/src/openvpn/options.c
+++ b/src/openvpn/options.c
@@ -3317,14 +3317,8 @@  check_file_access_chroot(const char *chroot, const int type, const char *file, c
     {
         struct gc_arena gc = gc_new();
         struct buffer chroot_file;
-        int len = 0;
-
-        /* Build up a new full path including chroot directory */
-        len = strlen(chroot) + strlen(PATH_SEPARATOR_STR) + strlen(file) + 1;
-        chroot_file = alloc_buf_gc(len, &gc);
-        buf_printf(&chroot_file, "%s%s%s", chroot, PATH_SEPARATOR_STR, file);
-        ASSERT(chroot_file.len > 0);
 
+        chroot_file = prepend_chroot(chroot, file, &gc);
         ret = check_file_access(type, BSTR(&chroot_file), mode, opt);
         gc_free(&gc);
     }
diff --git a/src/openvpn/ssl.c b/src/openvpn/ssl.c
index d8662d00..8782b140 100644
--- a/src/openvpn/ssl.c
+++ b/src/openvpn/ssl.c
@@ -584,7 +584,7 @@  tls_ctx_reload_crl(struct tls_root_ctx *ssl_ctx, const char *crl_file,
  * All files are in PEM format.
  */
 void
-init_ssl(const struct options *options, struct tls_root_ctx *new_ctx)
+init_ssl(const struct options *options, struct tls_root_ctx *new_ctx, bool in_chroot)
 {
     ASSERT(NULL != new_ctx);
 
@@ -702,7 +702,23 @@  init_ssl(const struct options *options, struct tls_root_ctx *new_ctx)
     /* Read CRL */
     if (options->crl_file && !(options->ssl_flags & SSLF_CRL_VERIFY_DIR))
     {
-        tls_ctx_reload_crl(new_ctx, options->crl_file, options->crl_file_inline);
+        /* If we're running with the chroot option, we may run init_ssl() before
+         * and after chroot-ing. We can use the crl_file path as-is if we're
+         * not going to chroot, or if we already are inside the chroot.
+         *
+         * If we're going to chroot later, we need to prefix the path of the
+         * chroot directory to crl_file. */
+        if (options->chroot_dir == NULL || in_chroot || options->crl_file_inline)
+        {
+            tls_ctx_reload_crl(new_ctx, options->crl_file, options->crl_file_inline);
+        }
+        else
+        {
+            struct gc_arena gc = gc_new();
+            struct buffer crl_file_buf = prepend_chroot(options->chroot_dir, options->crl_file, &gc);
+            tls_ctx_reload_crl(new_ctx, BSTR(&crl_file_buf), options->crl_file_inline);
+            gc_free(&gc);
+        }
     }
 
     /* Once keys and cert are loaded, load ECDH parameters */
diff --git a/src/openvpn/ssl.h b/src/openvpn/ssl.h
index 300a70d3..45ebe720 100644
--- a/src/openvpn/ssl.h
+++ b/src/openvpn/ssl.h
@@ -159,7 +159,7 @@  void free_ssl_lib(void);
  * Build master SSL context object that serves for the whole of OpenVPN
  * instantiation
  */
-void init_ssl(const struct options *options, struct tls_root_ctx *ctx);
+void init_ssl(const struct options *options, struct tls_root_ctx *ctx, bool in_chroot);
 
 /** @addtogroup control_processor
  *  @{ */