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afa58b7384
ncsi_send_cmd_nl() takes the number of bytes to copy from the
attacker-controlled ncsi_pkt_hdr.length field of the in-band packet
header, while the source buffer is the NCSI_ATTR_DATA netlink
attribute whose readable size is nla_len() - sizeof(ncsi_pkt_hdr).
The two length sources are never cross-checked: only
nla_len() >= sizeof(struct ncsi_pkt_hdr) is enforced.
With hdr->length set larger than the attribute payload (up to 65535
against at most 2032 readable bytes), ncsi_cmd_handler_oem() copies
past the end of the netlink attribute buffer with unsafe_memcpy(),
leaking up to ~64KB of kernel heap memory into the transmitted NCSI
command packet. The destination skb is sized by the declared payload,
so the write side does not overflow - this is a pure OOB read /
information leak, reachable with CAP_NET_ADMIN on systems with a
registered NCSI device (e.g. OpenBMC on Aspeed BMC SoCs, where
NET_NCSI=y is standard).
Reject commands whose declared payload extends past the end of the
data attribute.
The issue was found by the autokbug dynamic kernel fuzzer at Tencent
Yunding Lab.
Fixes:
|
||
|---|---|---|
| .. | ||
| internal.h | ||
| Kconfig | ||
| Makefile | ||
| ncsi-aen.c | ||
| ncsi-cmd.c | ||
| ncsi-manage.c | ||
| ncsi-netlink.c | ||
| ncsi-netlink.h | ||
| ncsi-pkt.h | ||
| ncsi-rsp.c | ||