[PATCH]: mmap packet socket information leak (trivial)

[Gianni Tedesco <gianni@ecsc.co.uk>]

Hi,

Here is a quick patch which blanks the mmap() packet socket buffer areas
before using them. Previously you would get uninitialised data inbetween
the data structures where they are TPACKET_ALIGNED().

The root user could potentially unwittingly save this data to a file and
distribute it not knowing his password was in it or whatever... Not very
likely but its worth fixing IMHO :)

Regards

diff -urN linux.orig/net/packet/af_packet.c linux/net/packet/af_packet.c
--- linux.orig/net/packet/af_packet.c	Wed May 29 12:30:10 2002
+++ linux/net/packet/af_packet.c	Wed May 29 12:29:10 2002
@@ -1679,6 +1679,7 @@
 			int k;
 
 			for (k=0; k<frames_per_block; k++, l++) {
+				memset((void *)ptr, 0, req->tp_frame_size);
 				io_vec[l] = (struct tpacket_hdr*)ptr;
 				io_vec[l]->tp_status = TP_STATUS_KERNEL;
 				ptr += req->tp_frame_size;

-- 
// Gianni Tedesco <gianni@ecsc.co.uk>
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