On 22 April 2015 at 16:45, Stefan Roese sr@denx.de wrote:
On 22.04.2015 13:11, Jagan Teki wrote:
On 12.01.2015 22:10, Wolfgang Denk wrote:
Should we add a memset(buf, 0, sizeof(buf)) before the memcpy() to prevent information from earlier activities to leak?
"buf" points to the new data to be written into the flash. We're overwriting the first "len" bytes of "cmp_buf" with this data.
Oh, sorry for the mixup. Then cmp_buf should be cleared (or at elast the remaining, unused part).
No. cmp_buf contains the original data from the flash. And only the beginning of this buffer is overwritten with the new data from "buf". So, the result of the memcpy() is that "cmp_buf" contains the data that should be written into the flash. Its a combination of the "original data" and the "new data".
I don't see why we should erase anything there. Perhaps I'm missing something though.
You are leaking data. This could contain "interesting" information; see the OpenSSL “Heartbleed” vulnerability for a (nasty) example what information leakage can do.
There is nothing leaking here. When anything would be zeroed out, the resulting buffer would not be the one that should be used.
I think this thread link got stopped any further update on this.
I would have thought that this patch had been applied some time ago. If not, then please do.
Applied to u-boot-spi/master
thanks!