| Message ID | 20250307074303.1497911-1-edumazet@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 0a5c8b2c8ccbd5987f5d05c6ad6740cdb2e467e8 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next] bpf: fix a possible NULL deref in bpf_map_offload_map_alloc() | expand |
On 03/07, Eric Dumazet wrote: > Call bpf_dev_offload_check() before netdev_lock_ops(). > > This is needed if attr->map_ifindex is not valid. > > Oops: general protection fault, probably for non-canonical address 0xdffffc0000000197: 0000 [#1] PREEMPT SMP KASAN PTI > KASAN: null-ptr-deref in range [0x0000000000000cb8-0x0000000000000cbf] > RIP: 0010:netdev_need_ops_lock include/linux/netdevice.h:2792 [inline] > RIP: 0010:netdev_lock_ops include/linux/netdevice.h:2803 [inline] > RIP: 0010:bpf_map_offload_map_alloc+0x19a/0x910 kernel/bpf/offload.c:533 > Call Trace: > <TASK> > map_create+0x946/0x11c0 kernel/bpf/syscall.c:1455 > __sys_bpf+0x6d3/0x820 kernel/bpf/syscall.c:5777 > __do_sys_bpf kernel/bpf/syscall.c:5902 [inline] > __se_sys_bpf kernel/bpf/syscall.c:5900 [inline] > __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5900 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 > > Fixes: 97246d6d21c2 ("net: hold netdev instance lock during ndo_bpf") > Reported-by: syzbot+0c7bfd8cf3aecec92708@syzkaller.appspotmail.com > Closes: https://lore.kernel.org/netdev/67caa2b1.050a0220.15b4b9.0077.GAE@google.com/T/#u > Signed-off-by: Eric Dumazet <edumazet@google.com> Oops, thanks for a quick fix! Acked-by: Stanislav Fomichev <sdf@fomichev.me>
Hello: This patch was applied to netdev/net-next.git (main) by Jakub Kicinski <kuba@kernel.org>: On Fri, 7 Mar 2025 07:43:02 +0000 you wrote: > Call bpf_dev_offload_check() before netdev_lock_ops(). > > This is needed if attr->map_ifindex is not valid. > > Oops: general protection fault, probably for non-canonical address 0xdffffc0000000197: 0000 [#1] PREEMPT SMP KASAN PTI > KASAN: null-ptr-deref in range [0x0000000000000cb8-0x0000000000000cbf] > RIP: 0010:netdev_need_ops_lock include/linux/netdevice.h:2792 [inline] > RIP: 0010:netdev_lock_ops include/linux/netdevice.h:2803 [inline] > RIP: 0010:bpf_map_offload_map_alloc+0x19a/0x910 kernel/bpf/offload.c:533 > Call Trace: > <TASK> > map_create+0x946/0x11c0 kernel/bpf/syscall.c:1455 > __sys_bpf+0x6d3/0x820 kernel/bpf/syscall.c:5777 > __do_sys_bpf kernel/bpf/syscall.c:5902 [inline] > __se_sys_bpf kernel/bpf/syscall.c:5900 [inline] > __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5900 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 > > [...] Here is the summary with links: - [net-next] bpf: fix a possible NULL deref in bpf_map_offload_map_alloc() https://git.kernel.org/netdev/net-next/c/0a5c8b2c8ccb You are awesome, thank you!
diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c index a10153c3be2df675af49f0ad9c70b64b83593f45..4f707cfe7f103c8a480d534cddcc75e958f0bd57 100644 --- a/kernel/bpf/offload.c +++ b/kernel/bpf/offload.c @@ -530,11 +530,12 @@ struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr) bpf_map_init_from_attr(&offmap->map, attr); rtnl_lock(); offmap->netdev = __dev_get_by_index(net, attr->map_ifindex); - netdev_lock_ops(offmap->netdev); - down_write(&bpf_devs_lock); err = bpf_dev_offload_check(offmap->netdev); if (err) - goto err_unlock; + goto err_unlock_rtnl; + + netdev_lock_ops(offmap->netdev); + down_write(&bpf_devs_lock); ondev = bpf_offload_find_netdev(offmap->netdev); if (!ondev) { @@ -556,6 +557,7 @@ struct bpf_map *bpf_map_offload_map_alloc(union bpf_attr *attr) err_unlock: up_write(&bpf_devs_lock); netdev_unlock_ops(offmap->netdev); +err_unlock_rtnl: rtnl_unlock(); bpf_map_area_free(offmap); return ERR_PTR(err);
Call bpf_dev_offload_check() before netdev_lock_ops(). This is needed if attr->map_ifindex is not valid. Oops: general protection fault, probably for non-canonical address 0xdffffc0000000197: 0000 [#1] PREEMPT SMP KASAN PTI KASAN: null-ptr-deref in range [0x0000000000000cb8-0x0000000000000cbf] RIP: 0010:netdev_need_ops_lock include/linux/netdevice.h:2792 [inline] RIP: 0010:netdev_lock_ops include/linux/netdevice.h:2803 [inline] RIP: 0010:bpf_map_offload_map_alloc+0x19a/0x910 kernel/bpf/offload.c:533 Call Trace: <TASK> map_create+0x946/0x11c0 kernel/bpf/syscall.c:1455 __sys_bpf+0x6d3/0x820 kernel/bpf/syscall.c:5777 __do_sys_bpf kernel/bpf/syscall.c:5902 [inline] __se_sys_bpf kernel/bpf/syscall.c:5900 [inline] __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5900 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 Fixes: 97246d6d21c2 ("net: hold netdev instance lock during ndo_bpf") Reported-by: syzbot+0c7bfd8cf3aecec92708@syzkaller.appspotmail.com Closes: https://lore.kernel.org/netdev/67caa2b1.050a0220.15b4b9.0077.GAE@google.com/T/#u Signed-off-by: Eric Dumazet <edumazet@google.com> --- kernel/bpf/offload.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)