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([2001:41d0:303:db6b::]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4923fc47720sm102995695e9.0.2026.06.19.05.00.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 19 Jun 2026 05:00:27 -0700 (PDT) From: Tristan Madani To: miklos@szeredi.hu Cc: amir73il@gmail.com, linux-fsdevel@vger.kernel.org, stable@vger.kernel.org, tristan@talencesecurity.com Subject: [PATCH] fuse: check fi is not NULL before calling fuse_passthrough_release() Date: Fri, 19 Jun 2026 12:00:26 +0000 Message-ID: <20260619120026.2630196-1-tristmd@gmail.com> X-Mailer: git-send-email 2.47.3 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Tristan Madani fuse_create_open() calls fuse_sync_release() with a NULL fuse_inode when fuse_iget() fails. This propagates to fuse_prepare_release(), which passes the NULL fi to fuse_inode_backing() via the fuse_passthrough_release() call, resulting in a NULL pointer dereference. The existing comment in fuse_prepare_release() documents that the inode can be NULL on the error path of fuse_create_open(), and the fi->lock access below is already guarded with if (likely(fi)), but the passthrough release path added by commit 4a90451bbc7f ("fuse: implement open in passthrough mode") was not given the same protection. Add the missing NULL check for fi before calling fuse_passthrough_release(). Found by syzkaller. Fixes: 4a90451bbc7f ("fuse: implement open in passthrough mode") Cc: stable@vger.kernel.org Signed-off-by: Tristan Madani --- fs/fuse/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index c59452d60b8d..9b368eab159c 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -313,7 +313,7 @@ static void fuse_prepare_release(struct fuse_inode *fi, struct fuse_file *ff, struct fuse_conn *fc = ff->fm->fc; struct fuse_release_args *ra = &ff->args->release_args; - if (fuse_file_passthrough(ff)) + if (fi && fuse_file_passthrough(ff)) fuse_passthrough_release(ff, fuse_inode_backing(fi)); /* Inode is NULL on error path of fuse_create_open() */ -- 2.47.3