Fixed returning an error condition to ioctl(2) (#641)

When returning a negative error code by ->ioctl() to the high level
interface, no error is propagated to the low level, and the reply
message to the kernel is shown as successful.

A negative result is however returned to kernel, so the kernel can
detect the bad condition, but this appears to not be the case since
kernel 5.15.

The proposed fix is more in line with the usual processing of errors
in fuse, taking into account that ioctl(2) always returns a non-negative
value in the absence of errors.

Co-authored-by: Jean-Pierre André <jpandre@users.sourceforge.net>

diff --git a/ChangeLog.rst b/ChangeLog.rst
index b97d61d0ffa94a9d4eca415c4b58a3f1db92b9a2..2dd8954336b31a7e2f6e15be1bf9b04e6d45aa1c 100644 (file)
--- a/ChangeLog.rst
+++ b/ChangeLog.rst
@@ -1,3 +1,5 @@
+* Fixed returning an error condition to ioctl(2)
+
 libfuse 3.10.5 (2021-09-06)
 ===========================
 

diff --git a/lib/fuse.c b/lib/fuse.c
index f732470cea0bbb57293a097a529916e2d4c52147..91a4b708abc4d9228693323c690cd973d0f80580 100644 (file)
--- a/lib/fuse.c
+++ b/lib/fuse.c
@@ -4289,6 +4289,8 @@ static void fuse_lib_ioctl(fuse_req_t req, fuse_ino_t ino, unsigned int cmd,
        fuse_finish_interrupt(f, req, &d);
        free_path(f, ino, path);
 
+       if (err < 0)
+               goto err;
        fuse_reply_ioctl(req, err, out_buf, out_bufsz);
        goto out;
 err: