[PATCH] gve: Fix a possible invalid memory access

From: Christophe JAILLET
Date: Sun Oct 24 2021 - 07:52:47 EST


It is spurious to allocate a bitmap for 'num_qpls' bits and record the
size of this bitmap with another value.

'qpl_map_size' is used in 'drivers/net/ethernet/google/gve/gve.h' with
'find_[first|next]_zero_bit()'.
So, it looks that memory after the allocated 'qpl_id_map' could be
scanned.

Remove the '* BITS_PER_BYTE' to have allocation and length be the same.

Fixes: f5cedc84a30d ("gve: Add transmit and receive support")
Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
---
This patch is completely speculative and un-tested!
You'll be warned.
---
drivers/net/ethernet/google/gve/gve_main.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/google/gve/gve_main.c b/drivers/net/ethernet/google/gve/gve_main.c
index 7647cd05b1d2..19fe9e9b62f5 100644
--- a/drivers/net/ethernet/google/gve/gve_main.c
+++ b/drivers/net/ethernet/google/gve/gve_main.c
@@ -866,7 +866,7 @@ static int gve_alloc_qpls(struct gve_priv *priv)
}

priv->qpl_cfg.qpl_map_size = BITS_TO_LONGS(num_qpls) *
- sizeof(unsigned long) * BITS_PER_BYTE;
+ sizeof(unsigned long);
priv->qpl_cfg.qpl_id_map = kvcalloc(BITS_TO_LONGS(num_qpls),
sizeof(unsigned long), GFP_KERNEL);
if (!priv->qpl_cfg.qpl_id_map) {
--
2.30.2