CVE-2022-49871

In the Linux kernel, the following vulnerability has been resolved:

net: tun: Fix memory leaks of napigetfrags

kmemleak reports after running test_progs:

unreferenced object 0xffff8881b1672dc0 (size 232): comm "testprogs", pid 394388, jiffies 4354712116 (age 841.975s) hex dump (first 32 bytes): e0 84 d7 a8 81 88 ff ff 80 2c 67 b1 81 88 ff ff .........,g..... 00 40 c5 9b 81 88 ff ff 00 00 00 00 00 00 00 00 .@.............. backtrace: [<00000000c8f01748>] napiskbcacheget+0xd4/0x150 [<0000000041c7fc09>] __napibuildskb+0x15/0x50 [<00000000431c7079>] __napiallocskb+0x26e/0x540 [<000000003ecfa30e>] napigetfrags+0x59/0x140 [<0000000099b2199e>] tungetuser+0x183d/0x3bb0 [tun] [<000000008a5adef0>] tunchrwriteiter+0xc0/0x1b1 [tun] [<0000000049993ff4>] doiterreadvwritev+0x19f/0x320 [<000000008f338ea2>] doiterwrite+0x135/0x630 [<000000008a3377a4>] vfswritev+0x12e/0x440 [<00000000a6b5639a>] dowritev+0x104/0x280 [<00000000ccf065d8>] dosyscall64+0x3b/0x90 [<00000000d776e329>] entrySYSCALL64afterhwframe+0x63/0xcd

The issue occurs in the following scenarios: tungetuser() napigrofrags() napifragsfinish() case GRONORMAL: gronormalone() listaddtail(&skb->list, &napi->rxlist); <-- While napi->rxcount < READONCE(gronormalbatch), <-- gronormallist() is not called, napi->rxlist is not empty <-- not ask to complete the gro work, will cause memory leaks in <-- following tunnapidel() ... tunnapidel() netifnapi_del() _netifnapidel() <-- &napi->rxlist is not empty, which caused memory leaks

To fix, add napicomplete() after napigro_frags().