vxlan: vnifilter: enforce exact length of GROUP/GROUP6 attributes

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The VXLAN VNI filter entry policy declares the GROUP/GROUP6 address
attributes as NLA_BINARY with only a maximum length, so validate_nla()
accepts a payload shorter than the address. The GROUP consumer reads it
with nla_get_in_addr(), an unconditional 4-byte load, so a short
attribute over-reads up to 3 bytes of uninitialised slab data, which are
stored into remote_ip and echoed back via RTM_GETTUNNEL, disclosing
kernel memory.

Switch both entries to NLA_POLICY_EXACT_LEN() so the validator rejects
any GROUP/GROUP6 that is not exactly 4 / 16 bytes; a valid address is
always sent at full width.

Fixes: f9c4bb0b24 ("vxlan: vni filtering support on collect metadata device")
Reported-by: Weiming Shi <bestswngs@gmail.com>
Signed-off-by: Xiang Mei <xmei5@asu.edu>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20260812215341.763123-1-xmei5@asu.edu
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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Xiang Mei 2026-08-12 14:53:41 -07:00 • committed by Jakub Kicinski

parent ba9189c1d0

commit 984f831dda

1 changed files with 2 additions and 4 deletions

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drivers/net/vxlan/vxlan_vnifilter.c

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