On Fri, Jun 29, 2018 at 11:48:50AM -0700, Kees Cook wrote: > In the quest to remove all stack VLA usage from the kernel[1], this > switches to using a kmalloc-allocated buffer instead of stack space. > This should be fine since the existing routine is allocating memory > too. > > [1] > https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qpxydaacu1rq...@mail.gmail.com > > Cc: David Daney <[email protected]> > Cc: Jan Glauber <[email protected]> > Cc: Borislav Petkov <[email protected]> > Cc: Mauro Carvalho Chehab <[email protected]> > Cc: [email protected] > Signed-off-by: Kees Cook <[email protected]>
Acked-by: Jan Glauber <[email protected]> thanks, Jan > --- > drivers/edac/thunderx_edac.c | 14 +++++++++----- > 1 file changed, 9 insertions(+), 5 deletions(-) > > diff --git a/drivers/edac/thunderx_edac.c b/drivers/edac/thunderx_edac.c > index 4803c6468bab..c009d94f40c5 100644 > --- a/drivers/edac/thunderx_edac.c > +++ b/drivers/edac/thunderx_edac.c > @@ -408,26 +408,29 @@ static ssize_t thunderx_lmc_inject_ecc_write(struct > file *file, > size_t count, loff_t *ppos) > { > struct thunderx_lmc *lmc = file->private_data; > - > unsigned int cline_size = cache_line_size(); > - > - u8 tmp[cline_size]; > + u8 *tmp; > void __iomem *addr; > unsigned int offs, timeout = 100000; > > atomic_set(&lmc->ecc_int, 0); > > lmc->mem = alloc_pages_node(lmc->node, GFP_KERNEL, 0); > - > if (!lmc->mem) > return -ENOMEM; > > + tmp = kmalloc(cline_size, GFP_KERNEL); > + if (!tmp) { > + __free_pages(lmc->mem, 0); > + return -ENOMEM; > + } > + > addr = page_address(lmc->mem); > > while (!atomic_read(&lmc->ecc_int) && timeout--) { > stop_machine(inject_ecc_fn, lmc, NULL); > > - for (offs = 0; offs < PAGE_SIZE; offs += sizeof(tmp)) { > + for (offs = 0; offs < PAGE_SIZE; offs += cline_size) { > /* > * Do a load from the previously rigged location > * This should generate an error interrupt. > @@ -437,6 +440,7 @@ static ssize_t thunderx_lmc_inject_ecc_write(struct file > *file, > } > } > > + kfree(tmp); > __free_pages(lmc->mem, 0); > > return count; > -- > 2.17.1 > > > -- > Kees Cook > Pixel Security
