| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2021-47563: ice: avoid bpf_prog refcount underflow |
| |
| Description |
| =========== |
| |
| In the Linux kernel, the following vulnerability has been resolved: |
| |
| ice: avoid bpf_prog refcount underflow |
| |
| Ice driver has the routines for managing XDP resources that are shared |
| between ndo_bpf op and VSI rebuild flow. The latter takes place for |
| example when user changes queue count on an interface via ethtool's |
| set_channels(). |
| |
| There is an issue around the bpf_prog refcounting when VSI is being |
| rebuilt - since ice_prepare_xdp_rings() is called with vsi->xdp_prog as |
| an argument that is used later on by ice_vsi_assign_bpf_prog(), same |
| bpf_prog pointers are swapped with each other. Then it is also |
| interpreted as an 'old_prog' which in turn causes us to call |
| bpf_prog_put on it that will decrement its refcount. |
| |
| Below splat can be interpreted in a way that due to zero refcount of a |
| bpf_prog it is wiped out from the system while kernel still tries to |
| refer to it: |
| |
| [ 481.069429] BUG: unable to handle page fault for address: ffffc9000640f038 |
| [ 481.077390] #PF: supervisor read access in kernel mode |
| [ 481.083335] #PF: error_code(0x0000) - not-present page |
| [ 481.089276] PGD 100000067 P4D 100000067 PUD 1001cb067 PMD 106d2b067 PTE 0 |
| [ 481.097141] Oops: 0000 [#1] PREEMPT SMP PTI |
| [ 481.101980] CPU: 12 PID: 3339 Comm: sudo Tainted: G OE 5.15.0-rc5+ #1 |
| [ 481.110840] Hardware name: Intel Corp. GRANTLEY/GRANTLEY, BIOS GRRFCRB1.86B.0276.D07.1605190235 05/19/2016 |
| [ 481.122021] RIP: 0010:dev_xdp_prog_id+0x25/0x40 |
| [ 481.127265] Code: 80 00 00 00 00 0f 1f 44 00 00 89 f6 48 c1 e6 04 48 01 fe 48 8b 86 98 08 00 00 48 85 c0 74 13 48 8b 50 18 31 c0 48 85 d2 74 07 <48> 8b 42 38 8b 40 20 c3 48 8b 96 90 08 00 00 eb e8 66 2e 0f 1f 84 |
| [ 481.148991] RSP: 0018:ffffc90007b63868 EFLAGS: 00010286 |
| [ 481.155034] RAX: 0000000000000000 RBX: ffff889080824000 RCX: 0000000000000000 |
| [ 481.163278] RDX: ffffc9000640f000 RSI: ffff889080824010 RDI: ffff889080824000 |
| [ 481.171527] RBP: ffff888107af7d00 R08: 0000000000000000 R09: ffff88810db5f6e0 |
| [ 481.179776] R10: 0000000000000000 R11: ffff8890885b9988 R12: ffff88810db5f4bc |
| [ 481.188026] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 |
| [ 481.196276] FS: 00007f5466d5bec0(0000) GS:ffff88903fb00000(0000) knlGS:0000000000000000 |
| [ 481.205633] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 |
| [ 481.212279] CR2: ffffc9000640f038 CR3: 000000014429c006 CR4: 00000000003706e0 |
| [ 481.220530] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 |
| [ 481.228771] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 |
| [ 481.237029] Call Trace: |
| [ 481.239856] rtnl_fill_ifinfo+0x768/0x12e0 |
| [ 481.244602] rtnl_dump_ifinfo+0x525/0x650 |
| [ 481.249246] ? __alloc_skb+0xa5/0x280 |
| [ 481.253484] netlink_dump+0x168/0x3c0 |
| [ 481.257725] netlink_recvmsg+0x21e/0x3e0 |
| [ 481.262263] ____sys_recvmsg+0x87/0x170 |
| [ 481.266707] ? __might_fault+0x20/0x30 |
| [ 481.271046] ? _copy_from_user+0x66/0xa0 |
| [ 481.275591] ? iovec_from_user+0xf6/0x1c0 |
| [ 481.280226] ___sys_recvmsg+0x82/0x100 |
| [ 481.284566] ? sock_sendmsg+0x5e/0x60 |
| [ 481.288791] ? __sys_sendto+0xee/0x150 |
| [ 481.293129] __sys_recvmsg+0x56/0xa0 |
| [ 481.297267] do_syscall_64+0x3b/0xc0 |
| [ 481.301395] entry_SYSCALL_64_after_hwframe+0x44/0xae |
| [ 481.307238] RIP: 0033:0x7f5466f39617 |
| [ 481.311373] Code: 0c 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb bd 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 2f 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 89 54 24 1c 48 89 74 24 10 |
| [ 481.342944] RSP: 002b:00007ffedc7f4308 EFLAGS: 00000246 ORIG_RAX: 000000000000002f |
| [ 481.361783] RAX: ffffffffffffffda RBX: 00007ffedc7f5460 RCX: 00007f5466f39617 |
| [ 481.380278] RDX: 0000000000000000 RSI: 00007ffedc7f5360 RDI: 0000000000000003 |
| [ 481.398500] RBP: 00007ffedc7f53f0 R08: 0000000000000000 R09: 000055d556f04d50 |
| [ 481.416463] R10: 0000000000000077 R11: 0000000000000246 R12: 00007ffedc7f5360 |
| [ 481.434131] R13: 00007ffedc7f5350 R14: 00007ffedc7f5344 R15: 0000000000000e98 |
| [ 481.451520] Modules linked in: ice(OE) af_packet binfmt_misc nls_iso8859_1 ipmi_ssif intel_rapl_msr intel_rapl_common x86_pkg_temp_thermal intel_powerclamp mxm_wmi mei_me coretemp mei ipmi_si ipmi_msghandler wmi acpi_pad acpi_power_meter ip_tables x_tables autofs4 crct10dif_pclmul crc32_pclmul ghash_clmulni_intel aesni_intel ahci crypto_simd cryptd libahci lpc_ich [last unloaded: ice] |
| [ 481.528558] CR2: ffffc9000640f038 |
| [ 481.542041] ---[ end trace d1f24c9ecf5b61c1 ]--- |
| |
| Fix this by only calling ice_vsi_assign_bpf_prog() inside |
| ice_prepare_xdp_rings() when current vsi->xdp_prog pointer is NULL. |
| This way set_channels() flow will not attempt to swap the vsi->xdp_prog |
| pointers with itself. |
| |
| Also, sprinkle around some comments that provide a reasoning about |
| correlation between driver and kernel in terms of bpf_prog refcount. |
| |
| The Linux kernel CVE team has assigned CVE-2021-47563 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 5.5 with commit efc2214b6047b6f5b4ca53151eba62521b9452d6 and fixed in 5.10.83 with commit e65a8707b4cd756d26d246bb2b9fab06eebafac1 |
| Issue introduced in 5.5 with commit efc2214b6047b6f5b4ca53151eba62521b9452d6 and fixed in 5.15.6 with commit 1f10b09ccc832698ef4624a6ab9a213b6ccbda76 |
| Issue introduced in 5.5 with commit efc2214b6047b6f5b4ca53151eba62521b9452d6 and fixed in 5.16 with commit f65ee535df775a13a1046c0a0b2d72db342f8a5b |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2021-47563 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| drivers/net/ethernet/intel/ice/ice_main.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/e65a8707b4cd756d26d246bb2b9fab06eebafac1 |
| https://git.kernel.org/stable/c/1f10b09ccc832698ef4624a6ab9a213b6ccbda76 |
| https://git.kernel.org/stable/c/f65ee535df775a13a1046c0a0b2d72db342f8a5b |
