msizanoen1 209d35ee34 ipv6: fix memory leak in fib6_rule_suppress ... commit cdef485217d30382f3bf6448c54b4401648fe3f1 upstream. The kernel leaks memory when a `fib` rule is present in IPv6 nftables firewall rules and a suppress_prefix rule is present in the IPv6 routing rules (used by certain tools such as wg-quick). In such scenarios, every incoming packet will leak an allocation in `ip6_dst_cache` slab cache. After some hours of `bpftrace`-ing and source code reading, I tracked down the issue to ca7a03c417 ("ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule"). The problem with that change is that the generic `args->flags` always have `FIB_LOOKUP_NOREF` set[1][2] but the IPv6-specific flag `RT6_LOOKUP_F_DST_NOREF` might not be, leading to `fib6_rule_suppress` not decreasing the refcount when needed. How to reproduce: - Add the following nftables rule to a prerouting chain: meta nfproto ipv6 fib saddr . mark . iif oif missing drop This can be done with: sudo nft create table inet test sudo nft create chain inet test test_chain '{ type filter hook prerouting priority filter + 10; policy accept; }' sudo nft add rule inet test test_chain meta nfproto ipv6 fib saddr . mark . iif oif missing drop - Run: sudo ip -6 rule add table main suppress_prefixlength 0 - Watch `sudo slabtop -o | grep ip6_dst_cache` to see memory usage increase with every incoming ipv6 packet. This patch exposes the protocol-specific flags to the protocol specific `suppress` function, and check the protocol-specific `flags` argument for RT6_LOOKUP_F_DST_NOREF instead of the generic FIB_LOOKUP_NOREF when decreasing the refcount, like this. [1]: ca7a03c417/net/ipv6/fib6_rules.c (L71) [2]: ca7a03c417/net/ipv6/fib6_rules.c (L99) Link: https://bugzilla.kernel.org/show_bug.cgi?id=215105 Fixes: ca7a03c417 ("ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule") Cc: stable@vger.kernel.org Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2021-12-08 09:03:21 +01:00
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acpi
asm-generic
clocksource
crypto
drm
dt-bindings
keys
kunit
kvm
linux	kprobes: Limit max data_size of the kretprobe instances	2021-12-08 09:03:20 +01:00
math-emu
media
memory	memory: renesas-rpc-if: Correct QSPI data transfer in Manual mode	2021-11-18 14:03:47 +01:00
misc
net	ipv6: fix memory leak in fib6_rule_suppress	2021-12-08 09:03:21 +01:00
pcmcia
ras
rdma	RDMA/netlink: Add __maybe_unused to static inline in C file	2021-11-26 10:39:21 +01:00
scsi
soc
sound	ALSA: hda: hdac_ext_stream: fix potential locking issues	2021-11-26 10:39:22 +01:00
target	scsi: target: Fix ordered tag handling	2021-11-26 10:39:11 +01:00
trace	f2fs: fix up f2fs_lookup tracepoints	2021-11-26 10:39:12 +01:00
uapi	net-zerocopy: Copy straggler unaligned data for TCP Rx. zerocopy.	2021-11-26 10:39:14 +01:00
vdso
video
xen	xen: sync include/xen/interface/io/ring.h with Xen's newest version	2021-12-01 09:19:09 +01:00