On Fri, Jun 19, 2020 at 03:19:21PM +0000, Oleksandr Andrushchenko wrote:
On 6/19/20 4:53 PM, Tom Rini wrote:
On Fri, Jun 19, 2020 at 11:22:18AM +0300, Oleksandr Andrushchenko wrote:
From: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com
While relocating FDT we reserve some memory for the new FDT and set the size of the FDT with that respect. But FDT may be placed at the end of the RAM leading to memory access beyond it. Fix this by copying exact FDT size bytes, not the reserved size.
Signed-off-by: Oleksandr Andrushchenko oleksandr_andrushchenko@epam.com
common/board_f.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/common/board_f.c b/common/board_f.c index 01194eaa0e4d..aa1285e94999 100644 --- a/common/board_f.c +++ b/common/board_f.c @@ -670,7 +670,7 @@ static int reloc_fdt(void) if (gd->flags & GD_FLG_SKIP_RELOC) return 0; if (gd->new_fdt) {
memcpy(gd->new_fdt, gd->fdt_blob, gd->fdt_size);
memcpy(gd->new_fdt, gd->fdt_blob, fdt_totalsize(gd->fdt_blob));So, I think the problem is placing the fdt so close to the end of memory and we need to fix that.
Exactly
With the above change, we won't copy past the end of memory
yes
but gd->fdt_blob + gd->fdt_size will still point past it, yes?
Not really as the next op after the memcpy will set fdt_blob to the new location
and it is safe to access the memory in [gd->fdt_blob; gd->fdt_blob + gd->fdt_size) range.
We only ensure we are copying the fdt itself, not also the reserved memory which
doesn't exist past the original fdt addresses
Ah, so I had something backwards then. We're fine because gd->new_fdt + gd->fdt_size is fine. Thanks!