| From e3d57c17f8280b2c782ef0254c0d7439a0b76caf Mon Sep 17 00:00:00 2001 |
| From: Jouni Hogander <jouni.hogander@unikie.com> |
| Date: Mon, 20 Jan 2020 09:51:03 +0200 |
| Subject: [PATCH] net-sysfs: Fix reference count leak |
| |
| commit cb626bf566eb4433318d35681286c494f04fedcc upstream. |
| |
| Netdev_register_kobject is calling device_initialize. In case of error |
| reference taken by device_initialize is not given up. |
| |
| Drivers are supposed to call free_netdev in case of error. In non-error |
| case the last reference is given up there and device release sequence |
| is triggered. In error case this reference is kept and the release |
| sequence is never started. |
| |
| Fix this by setting reg_state as NETREG_UNREGISTERED if registering |
| fails. |
| |
| This is the rootcause for couple of memory leaks reported by Syzkaller: |
| |
| BUG: memory leak unreferenced object 0xffff8880675ca008 (size 256): |
| comm "netdev_register", pid 281, jiffies 4294696663 (age 6.808s) |
| 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: |
| [<0000000058ca4711>] kmem_cache_alloc_trace+0x167/0x280 |
| [<000000002340019b>] device_add+0x882/0x1750 |
| [<000000001d588c3a>] netdev_register_kobject+0x128/0x380 |
| [<0000000011ef5535>] register_netdevice+0xa1b/0xf00 |
| [<000000007fcf1c99>] __tun_chr_ioctl+0x20d5/0x3dd0 |
| [<000000006a5b7b2b>] tun_chr_ioctl+0x2f/0x40 |
| [<00000000f30f834a>] do_vfs_ioctl+0x1c7/0x1510 |
| [<00000000fba062ea>] ksys_ioctl+0x99/0xb0 |
| [<00000000b1c1b8d2>] __x64_sys_ioctl+0x78/0xb0 |
| [<00000000984cabb9>] do_syscall_64+0x16f/0x580 |
| [<000000000bde033d>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 |
| [<00000000e6ca2d9f>] 0xffffffffffffffff |
| |
| BUG: memory leak |
| unreferenced object 0xffff8880668ba588 (size 8): |
| comm "kobject_set_nam", pid 286, jiffies 4294725297 (age 9.871s) |
| hex dump (first 8 bytes): |
| 6e 72 30 00 cc be df 2b nr0....+ |
| backtrace: |
| [<00000000a322332a>] __kmalloc_track_caller+0x16e/0x290 |
| [<00000000236fd26b>] kstrdup+0x3e/0x70 |
| [<00000000dd4a2815>] kstrdup_const+0x3e/0x50 |
| [<0000000049a377fc>] kvasprintf_const+0x10e/0x160 |
| [<00000000627fc711>] kobject_set_name_vargs+0x5b/0x140 |
| [<0000000019eeab06>] dev_set_name+0xc0/0xf0 |
| [<0000000069cb12bc>] netdev_register_kobject+0xc8/0x320 |
| [<00000000f2e83732>] register_netdevice+0xa1b/0xf00 |
| [<000000009e1f57cc>] __tun_chr_ioctl+0x20d5/0x3dd0 |
| [<000000009c560784>] tun_chr_ioctl+0x2f/0x40 |
| [<000000000d759e02>] do_vfs_ioctl+0x1c7/0x1510 |
| [<00000000351d7c31>] ksys_ioctl+0x99/0xb0 |
| [<000000008390040a>] __x64_sys_ioctl+0x78/0xb0 |
| [<0000000052d196b7>] do_syscall_64+0x16f/0x580 |
| [<0000000019af9236>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 |
| [<00000000bc384531>] 0xffffffffffffffff |
| |
| v3 -> v4: |
| Set reg_state to NETREG_UNREGISTERED if registering fails |
| |
| v2 -> v3: |
| * Replaced BUG_ON with WARN_ON in free_netdev and netdev_release |
| |
| v1 -> v2: |
| * Relying on driver calling free_netdev rather than calling |
| put_device directly in error path |
| |
| Reported-by: syzbot+ad8ca40ecd77896d51e2@syzkaller.appspotmail.com |
| Cc: David Miller <davem@davemloft.net> |
| Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com> |
| Signed-off-by: Jouni Hogander <jouni.hogander@unikie.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/net/core/dev.c b/net/core/dev.c |
| index 068365f1cd85..73fde53e4d7b 100644 |
| --- a/net/core/dev.c |
| +++ b/net/core/dev.c |
| @@ -8930,8 +8930,10 @@ int register_netdevice(struct net_device *dev) |
| goto err_uninit; |
| |
| ret = netdev_register_kobject(dev); |
| - if (ret) |
| + if (ret) { |
| + dev->reg_state = NETREG_UNREGISTERED; |
| goto err_uninit; |
| + } |
| dev->reg_state = NETREG_REGISTERED; |
| |
| __netdev_update_features(dev); |
| -- |
| 2.7.4 |
| |