From 3dc8fe4dca9cd3e4aa828ed36451e2bcfd2350da Mon Sep 17 00:00:00 2001 From: Jesper Juhl Date: Fri, 25 Mar 2011 01:51:37 +0800 Subject: [PATCH] autofs4: Do not potentially dereference NULL pointer returned by fget() in autofs_dev_ioctl_setpipefd() In fs/autofs4/dev-ioctl.c::autofs_dev_ioctl_setpipefd() we call fget(), which may return NULL, but we do not explicitly test for that NULL return so we may end up dereferencing a NULL pointer - bad. When I originally submitted this patch I had chosen EBUSY as the return value to use if this happens. Ian Kent was kind enough to explain why that would most likely be wrong and why EBADF should most likely be used instead. This version of the patch uses EBADF. Signed-off-by: Jesper Juhl Signed-off-by: Ian Kent Signed-off-by: Al Viro --- fs/autofs4/dev-ioctl.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c index 1442da4860e5..509fe1eb66ae 100644 --- a/fs/autofs4/dev-ioctl.c +++ b/fs/autofs4/dev-ioctl.c @@ -372,6 +372,10 @@ static int autofs_dev_ioctl_setpipefd(struct file *fp, return -EBUSY; } else { struct file *pipe = fget(pipefd); + if (!pipe) { + err = -EBADF; + goto out; + } if (!pipe->f_op || !pipe->f_op->write) { err = -EPIPE; fput(pipe); -- 2.30.2