Do not segv if NULL is passed for CTX in sendfd and receivefd.

* src/assuan-buffer.c (assuan_sendfd): Check that CTX is not NULL.
(assuan_receivefd): Ditto.
--

This change is to align the behaviour with that of assuan_send_data.

Suggested-by: Andre Heinecke.
Signed-off-by: Werner Koch <wk@gnupg.org>

3 files changed, 12 insertions, 4 deletions

diff --git a/doc/assuan.texi b/doc/assuan.texi
index 358357c..10b309c 100644
--- a/doc/assuan.texi
+++ b/doc/assuan.texi
@@ -1205,8 +1205,10 @@ The descriptor must be sent before the command is issued that makes
 use of the descriptor.
 
 Note that calling this function with a @var{ctx} of @code{NULL} and
-@var{fd} of @code{-1} can be used as a runtime test to check whether
-descriptor passing is available on the platform.  If it is, 0 is returned, otherwise an error with the error code @code{GPG_ERR_NOT_IMPLEMENTED}.
+@var{fd} of @code{ASSUAN_INVALID_FD} can be used as a runtime test to
+check whether descriptor passing is available on the platform:
+@code{0} is returned if descriptor passing is available, otherwise an
+error with the error code @code{GPG_ERR_NOT_IMPLEMENTED} is returned.
 @end deftypefun
 
 @anchor{function assuan_receivefd}
diff --git a/src/assuan-buffer.c b/src/assuan-buffer.c
index 04aff5a..b442b3d 100644
--- a/src/assuan-buffer.c
+++ b/src/assuan-buffer.c
@@ -524,6 +524,9 @@ assuan_sendfd (assuan_context_t ctx, assuan_fd_t fd)
   return _assuan_error (ctx, GPG_ERR_NOT_IMPLEMENTED);
 #endif
 
+  if (!ctx)
+    return _assuan_error (ctx, GPG_ERR_ASS_INV_VALUE);
+
   if (! ctx->engine.sendfd)
     return set_error (ctx, GPG_ERR_NOT_IMPLEMENTED,
 		      "server does not support sending and receiving "
@@ -534,6 +537,9 @@ assuan_sendfd (assuan_context_t ctx, assuan_fd_t fd)
 gpg_error_t
 assuan_receivefd (assuan_context_t ctx, assuan_fd_t *fd)
 {
+  if (!ctx)
+    return _assuan_error (ctx, GPG_ERR_ASS_INV_VALUE);
+
   if (! ctx->engine.receivefd)
     return set_error (ctx, GPG_ERR_NOT_IMPLEMENTED,
 		      "server does not support sending and receiving "
diff --git a/src/context.c b/src/context.c
index 62b7f57..147edae 100644
--- a/src/context.c
+++ b/src/context.c
@@ -183,8 +183,8 @@ void assuan_set_io_monitor (assuan_context_t ctx,
 
 
 /* Store the error in the context so that the error sending function
-  can take out a descriptive text.  Inside the assuan code, use the
-  macro set_error instead of this function. */
+   can take out a descriptive text.  Inside the assuan code, use the
+   macro set_error instead of this function. */
 gpg_error_t
 assuan_set_error (assuan_context_t ctx, gpg_error_t err, const char *text)
 {