lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite for Android: free password hash cracker in your pocket
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Tue, 7 Oct 2014 16:17:02 +0200
From:	Lothar Waßmann <>
To:	David Laight <David.Laight@...LAB.COM>
Cc:	"" <>,
	"David S. Miller" <>,
	Russell King <>,
	Frank Li <>,
	"Fabio Estevam" <>,
	"" <>
Subject: Re: [PATCH] net: fec: fix regression on i.MX28 introduced by
 rx_copybreak support


David Laight wrote:
> From: Lothar Waßmann
> > commit 1b7bde6d659d ("net: fec: implement rx_copybreak to improve rx performance")
> > introduced a regression for i.MX28. The swap_buffer() function doing
> > the endian conversion of the received data on i.MX28 may access memory
> > beyond the actual packet size in the DMA buffer. fec_enet_copybreak()
> > does not copy those bytes, so that the last bytes of a packet may be
> > filled with invalid data after swapping.
> > This will likely lead to checksum errors on received packets.
> > E.g. when trying to mount an NFS rootfs:
> > UDP: bad checksum. From to ulen 36
> > 
> > Do the byte swapping and copying to the new skb in one go if
> > necessary.
> ISTM that if you need to do the 'swap' you should copy the data regardless
> of the length.
The swap function has to look at at most 3 bytes beyond the actual
packet length. That is what the original swap_buffer() function does and
what the new function swap_buffer2(), that does the endian swapping
while copying to the new buffer, also does.

Lothar Waßmann

Ka-Ro electronics GmbH | Pascalstraße 22 | D - 52076 Aachen
Phone: +49 2408 1402-0 | Fax: +49 2408 1402-10
Geschäftsführer: Matthias Kaussen
Handelsregistereintrag: Amtsgericht Aachen, HRB 4996 |
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists