Wind River Support Network

Description

In the Linux kernel, the following vulnerability has been resolved:  net: ifb: report ethtool stats over num_tx_queues  ifb_dev_init() allocates dp->tx_private to dev->num_tx_queues entries via kzalloc_objs(*txp, dev->num_tx_queues). Both IFB per-queue RX and TX stats live in those entries: ifb_xmit() updates txp->rx_stats using the skb queue mapping, ifb_ri_tasklet() updates txp->tx_stats, and ifb_stats64() aggregates both over dev->num_tx_queues.  The ethtool stats callbacks instead size and walk the per-queue stats with dev->real_num_rx_queues and dev->real_num_tx_queues. With an asymmetric device where the RX queue count exceeds the TX queue count, for example:      ip link add name ifb10 numtxqueues 1 numrxqueues 8 type ifb     ethtool -S ifb10  ifb_get_ethtool_stats() indexes past the tx_private allocation and copies adjacent slab data through ETHTOOL_GSTATS.  Use dev->num_tx_queues consistently for the stats strings, the stats count, and the stats data walks. This reports one RX stats group and one TX stats group for each backing ifb_q_private entry, which is the queue set IFB can actually populate.  Reproduced under UML+KASAN at v7.1-rc2:    BUG: KASAN: slab-out-of-bounds in ifb_fill_stats_data+0x3c/0xae   Read of size 8 at addr 0000000062dbd228 by task ethtool/36   ifb_fill_stats_data+0x3c/0xae   ifb_get_ethtool_stats+0xc0/0x129   __dev_ethtool+0x1ca5/0x363c   dev_ethtool+0x123/0x1b3   dev_ioctl+0x56c/0x744   sock_do_ioctl+0x15f/0x1b2   sock_ioctl+0x4d5/0x50a   sys_ioctl+0xd8b/0xde9  With the patch applied, the same UML+KASAN repro is silent and ethtool -S ifb10 reports only the stats backed by the single allocated tx_private entry.