In the Linux kernel, the following vulnerability has been resolved:
mlxsw: spectrum_ipip: Fix memory leak when changing remote IPv6 address
The device stores IPv6 addresses that are used for encapsulation in linear memory that is managed by the driver.
Changing the remote address of an ip6gre net device never worked properly, but since cited commit the following reproducer [1] would result in a warning [2] and a memory leak [3]. The problem is that the new remote address is never added by the driver to its hash table (and therefore the device) and the old address is never removed from it.
Fix by programming the new address when the configuration of the ip6gre net device changes and removing the old one. If the address did not change, then the above would result in increasing the reference count of the address and then decreasing it.
[1] # ip link add name bla up type ip6gre local 2001:db8:1::1 remote 2001:db8:2::1 tos inherit ttl inherit # ip link set dev bla type ip6gre remote 2001:db8:3::1 # ip link del dev bla # devlink dev reload pci/0000:01:00.0
[2] WARNING: CPU: 0 PID: 1682 at drivers/net/ethernet/mellanox/mlxsw/spectrum.c:3002 mlxswspipv6addrput+0x140/0x1d0 Modules linked in: CPU: 0 UID: 0 PID: 1682 Comm: ip Not tainted 6.12.0-rc3-custom-g86b5b55bc835 #151 Hardware name: Nvidia SN5600/VMOD0013, BIOS 5.13 05/31/2023 RIP: 0010:mlxswspipv6addrput+0x140/0x1d0 [...] Call Trace: <TASK> mlxswsprouternetdeviceevent+0x55f/0x1240 notifiercallchain+0x5a/0xd0 callnetdevicenotifiersinfo+0x39/0x90 unregisternetdevicemanynotify+0x63e/0x9d0 rtnldellink+0x16b/0x3a0 rtnetlinkrcvmsg+0x142/0x3f0 netlinkrcvskb+0x50/0x100 netlinkunicast+0x242/0x390 netlinksendmsg+0x1de/0x420 syssendmsg+0x2bd/0x320 syssendmsg+0x9a/0xe0 _syssendmsg+0x7a/0xd0 dosyscall64+0x9e/0x1a0 entrySYSCALL64afterhwframe+0x77/0x7f
[3] unreferenced object 0xffff898081f597a0 (size 32): comm "ip", pid 1626, jiffies 4294719324 hex dump (first 32 bytes): 20 01 0d b8 00 02 00 00 00 00 00 00 00 00 00 01 ............... 21 49 61 83 80 89 ff ff 00 00 00 00 01 00 00 00 !Ia............. backtrace (crc fd9be911): [<00000000df89c55d>] kmalloccachenoprof+0x1da/0x260 [<00000000ff2a1ddb>] mlxswspipv6addrkvdlindexget+0x281/0x340 [<000000009ddd445d>] mlxswsprouternetdeviceevent+0x47b/0x1240 [<00000000743e7757>] notifiercallchain+0x5a/0xd0 [<000000007c7b9e13>] callnetdevicenotifiersinfo+0x39/0x90 [<000000002509645d>] registernetdevice+0x5f7/0x7a0 [<00000000c2e7d2a9>] ip6grenewlinkcommon.isra.0+0x65/0x130 [<0000000087cd6d8d>] ip6grenewlink+0x72/0x120 [<000000004df7c7cc>] rtnlnewlink+0x471/0xa20 [<0000000057ed632a>] rtnetlinkrcvmsg+0x142/0x3f0 [<0000000032e0d5b5>] netlinkrcvskb+0x50/0x100 [<00000000908bca63>] netlinkunicast+0x242/0x390 [<00000000cdbe1c87>] netlinksendmsg+0x1de/0x420 [<0000000011db153e>] syssendmsg+0x2bd/0x320 [<000000003b6d53eb>] _syssendmsg+0x9a/0xe0 [<00000000cae27c62>] _syssendmsg+0x7a/0xd0