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authorVladimir Oltean <vladimir.oltean@nxp.com>2023-01-24 14:08:01 +0300
committerDavid S. Miller <davem@davemloft.net>2023-01-25 12:56:31 +0300
commitc96de136329b38172f21214021fc30d67f05c399 (patch)
treeea1a151d7aefc6291aa8981bbb2eb442f108b31f /net/ethtool
parent99db6fb04317c289528e0d51d65c41938a375621 (diff)
downloadlinux-c96de136329b38172f21214021fc30d67f05c399.tar.xz
net: ethtool: fix NULL pointer dereference in stats_prepare_data()
In the following call path: ethnl_default_dumpit -> ethnl_default_dump_one -> ctx->ops->prepare_data -> stats_prepare_data struct genl_info *info will be passed as NULL, and stats_prepare_data() dereferences it while getting the extended ack pointer. To avoid that, just set the extack to NULL if "info" is NULL, since the netlink extack handling messages know how to deal with that. The pattern "info ? info->extack : NULL" is present in quite a few other "prepare_data" implementations, so it's clear that it's a more general problem to be dealt with at a higher level, but the code should have at least adhered to the current conventions to avoid the NULL dereference. Fixes: 04692c9020b7 ("net: ethtool: netlink: retrieve stats from multiple sources (eMAC, pMAC)") Reported-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Leon Romanovsky <leonro@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ethtool')
-rw-r--r--net/ethtool/stats.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/ethtool/stats.c b/net/ethtool/stats.c
index 7294be5855d4..010ed19ccc99 100644
--- a/net/ethtool/stats.c
+++ b/net/ethtool/stats.c
@@ -117,9 +117,9 @@ static int stats_prepare_data(const struct ethnl_req_info *req_base,
struct genl_info *info)
{
const struct stats_req_info *req_info = STATS_REQINFO(req_base);
+ struct netlink_ext_ack *extack = info ? info->extack : NULL;
struct stats_reply_data *data = STATS_REPDATA(reply_base);
enum ethtool_mac_stats_src src = req_info->src;
- struct netlink_ext_ack *extack = info->extack;
struct net_device *dev = reply_base->dev;
int ret;