On 1/6/2018 4:11 AM, Dan Williams wrote:
Static analysis reports that 'offset' may be a user controlled value
that is used as a data dependency reading from a raw6_frag_vec buffer.
In order to avoid potential leaks of kernel memory values, block
speculative execution of the instruction stream that could issue further
reads based on an invalid '*(rfv->c + offset)' value.
Based on an original patch by Elena Reshetova.
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Alexey Kuznetsov <kuznet@xxxxxxxxxxxxx>
Cc: Hideaki YOSHIFUJI <yoshfuji@xxxxxxxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Signed-off-by: Elena Reshetova <elena.reshetova@xxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
net/ipv6/raw.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 761a473a07c5..384e3d59d148 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
[...]
@@ -725,17 +726,17 @@ static int raw6_getfrag(void *from, char *to, int offset, int len, int odd,
struct sk_buff *skb)
{
struct raw6_frag_vec *rfv = from;
+ char *rfv_buf;
- if (offset < rfv->hlen) {
+ if ((rfv_buf = nospec_array_ptr(rfv->c, offset, rfv->hlen))) {
And here...
int copy = min(rfv->hlen - offset, len);
if (skb->ip_summed == CHECKSUM_PARTIAL)
- memcpy(to, rfv->c + offset, copy);
+ memcpy(to, rfv_buf, copy);
else
skb->csum = csum_block_add(
skb->csum,
- csum_partial_copy_nocheck(rfv->c + offset,
- to, copy, 0),
+ csum_partial_copy_nocheck(rfv_buf, to, copy, 0),
odd);
odd = 0;
MBR, Sergei
