libfdt: check for potential overrun in _fdt_splice()

This patch catches the conditions where:
 - 'splicepoint' is set to a point outside of [ fdt, fdt_totalsize(fdt) )
 - 'newlen' is negative, or 'splicepoint' plus 'newlen' results in overflow

Either of these cases can be caused by math which overflows in calling
functions, or by sizes specified through dynamic means.

Signed-off-by: Courtney Cavin <courtney.cavin@sonymobile.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
This commit is contained in:
Courtney Cavin 2015-12-01 16:43:10 -08:00 committed by David Gibson
parent f58799be13
commit d4c7c25c9e

View file

@ -101,6 +101,8 @@ static int _fdt_splice(void *fdt, void *splicepoint, int oldlen, int newlen)
if (((p + oldlen) < p) || ((p + oldlen) > end))
return -FDT_ERR_BADOFFSET;
if ((p < (char *)fdt) || ((end - oldlen + newlen) < (char *)fdt))
return -FDT_ERR_BADOFFSET;
if ((end - oldlen + newlen) > ((char *)fdt + fdt_totalsize(fdt)))
return -FDT_ERR_NOSPACE;
memmove(p + newlen, p + oldlen, end - p - oldlen);