Re: [PATCH v2] net: openvswitch: fix flow memory leak in ovs_flow_cmd_new

[Simon Horman]

On Thu, Feb 02, 2023 at 09:11:04AM +0100, Eelco Chaudron wrote:
> 
> 
> On 1 Feb 2023, at 22:02, Fedor Pchelkin wrote:
> 
> > Syzkaller reports a memory leak of new_flow in ovs_flow_cmd_new() as it is
> > not freed when an allocation of a key fails.
> >
> > BUG: memory leak
> > unreferenced object 0xffff888116668000 (size 632):
> >   comm "syz-executor231", pid 1090, jiffies 4294844701 (age 18.871s)
> >   hex dump (first 32 bytes):
> >     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> >     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
> >   backtrace:
> >     [<00000000defa3494>] kmem_cache_zalloc include/linux/slab.h:654 [inline]
> >     [<00000000defa3494>] ovs_flow_alloc+0x19/0x180 net/openvswitch/flow_table.c:77
> >     [<00000000c67d8873>] ovs_flow_cmd_new+0x1de/0xd40 net/openvswitch/datapath.c:957
> >     [<0000000010a539a8>] genl_family_rcv_msg_doit+0x22d/0x330 net/netlink/genetlink.c:739
> >     [<00000000dff3302d>] genl_family_rcv_msg net/netlink/genetlink.c:783 [inline]
> >     [<00000000dff3302d>] genl_rcv_msg+0x328/0x590 net/netlink/genetlink.c:800
> >     [<000000000286dd87>] netlink_rcv_skb+0x153/0x430 net/netlink/af_netlink.c:2515
> >     [<0000000061fed410>] genl_rcv+0x24/0x40 net/netlink/genetlink.c:811
> >     [<000000009dc0f111>] netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
> >     [<000000009dc0f111>] netlink_unicast+0x545/0x7f0 net/netlink/af_netlink.c:1339
> >     [<000000004a5ee816>] netlink_sendmsg+0x8e7/0xde0 net/netlink/af_netlink.c:1934
> >     [<00000000482b476f>] sock_sendmsg_nosec net/socket.c:651 [inline]
> >     [<00000000482b476f>] sock_sendmsg+0x152/0x190 net/socket.c:671
> >     [<00000000698574ba>] ____sys_sendmsg+0x70a/0x870 net/socket.c:2356
> >     [<00000000d28d9e11>] ___sys_sendmsg+0xf3/0x170 net/socket.c:2410
> >     [<0000000083ba9120>] __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439
> >     [<00000000c00628f8>] do_syscall_64+0x30/0x40 arch/x86/entry/common.c:46
> >     [<000000004abfdcf4>] entry_SYSCALL_64_after_hwframe+0x61/0xc6
> >
> > To fix this the patch rearranges the goto labels to reflect the order of
> > object allocations and adds appropriate goto statements on the error
> > paths.
> >
> > Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
> >
> > Fixes: 68bb10101e6b ("openvswitch: Fix flow lookup to use unmasked key")
> > Signed-off-by: Fedor Pchelkin <pchelkin@xxxxxxxxx>
> > Signed-off-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
> > ---
> > v1->v2: make goto statements structured
> 
> Thanks for fixing this, the changes look good.
> 
> Acked-by: Eelco Chaudron <echaudro@xxxxxxxxxx>

Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxx>