Re: [PATCH] usb: gadget: aspeed: fix buffer overflow
flat view
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: 2022-10-25 22:37:13
Also in:
linux-aspeed, linux-usb, lkml
On Tue, 2022-10-25 at 14:21 +0800, Lei Yu wrote:
This case is treated as an error and we do not care about the following data. Similarly, if we change the MTU in BMC and let BMC ping the OS, the OS kernel does not crash and it gets RX errors, and the ping fails. # ifconfig usb0 usb0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 ... RX packets 85 bytes 15380 (15.0 KiB) RX errors 51 dropped 0 overruns 0 frame 51 With this patch, we get the similar behavior on BMC that the RX errors are increasing.quoted
Additionally, I'm curious, why in this specific case is the device sending more data than the buffer can hold ? The MTU change should have resulted in buffers being re-allocated no ?The issue is found in a rare case during BIOS boot, we assume that BIOS is sending unexpected data to BMC for unknown reasons.
Ok thanks. Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
quoted
Or did you change the MTU on the remote and not on the local device ?Yes, the MTU is changed to 2000 in OS and kept 1500 on BMC, then the issue is reproduced. (see detailed steps in the above email). The reason we made the above test is because we are trying to reproduce the behavior as BIOS, and from the logs it looks like it's sending a packet larger than MTU. Then we tried to adjust the MTU on the OS side and reproduced the issue.
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