Messages in this thread | | | From | Jim Baxter <> | Subject | [PATCH V1 0/1] net: cdc_ncm: Fix TX zero padding | Date | Thu, 4 May 2017 20:41:34 +0100 |
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Analysis --------
The zero padding that is added to NTB's does not zero the memory correctly. This happens because the skb_put called within the memset in the line: memset(skb_put(skb_out, ctx->tx_max - skb_out->len), 0, ctx->tx_max - skb_out->len); causes the value of skb_out->len to be modified during the two uses of it within the above line. This causes non-zeroed data at the end of skb_out.
This issue was found when connecting between an ARM Sabre SD Host platform and a test box that was dropping the NDP's due to the non zeroed memory being identified as an error.
Solution --------
To resolve this I have cached the value of ctx->tx_max - skb_out->len before the memset operation.
Jim Baxter (1): net: cdc_ncm: Fix TX zero padding
drivers/net/usb/cdc_ncm.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)
-- 1.9.1
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