Commit 6e682d53 authored Mar 16, 2020 by Gabriel Krisman Bertazi Committed by Richard Weinberger Mar 29, 2020

um: ubd: Prevent buffer overrun on command completion



On the hypervisor side, when completing commands and the pipe is full,
we retry writing only the entries that failed, by offsetting
io_req_buffer, but we don't reduce the number of bytes written, which
can cause a buffer overrun of io_req_buffer, and write garbage to the
pipe.

Cc: Martyn Welch <martyn.welch@collabora.com>
Signed-off-by: Gabriel Krisman Bertazi <krisman@collabora.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

parent 598f5630

arch/um/drivers/ubd_kern.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -1607,7 +1607,9 @@ int io_thread(void *arg)
		written = 0;

		do {
		res = os_write_file(kernel_fd, ((char *) io_req_buffer) + written, n);
		res = os_write_file(kernel_fd,
		((char *) io_req_buffer) + written,
		n - written);
		if (res >= 0) {
		written += res;
		}

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