Upstream information

CVE-2021-47303 at MITRE

Description

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

bpf: Track subprog poke descriptors correctly and fix use-after-free

Subprograms are calling map_poke_track(), but on program release there is no
hook to call map_poke_untrack(). However, on program release, the aux memory
(and poke descriptor table) is freed even though we still have a reference to
it in the element list of the map aux data. When we run map_poke_run(), we then
end up accessing free'd memory, triggering KASAN in prog_array_map_poke_run():

[...]
[ 402.824689] BUG: KASAN: use-after-free in prog_array_map_poke_run+0xc2/0x34e
[ 402.824698] Read of size 4 at addr ffff8881905a7940 by task hubble-fgs/4337
[ 402.824705] CPU: 1 PID: 4337 Comm: hubble-fgs Tainted: G I 5.12.0+ #399
[ 402.824715] Call Trace:
[ 402.824719] dump_stack+0x93/0xc2
[ 402.824727] print_address_description.constprop.0+0x1a/0x140
[ 402.824736] ? prog_array_map_poke_run+0xc2/0x34e
[ 402.824740] ? prog_array_map_poke_run+0xc2/0x34e
[ 402.824744] kasan_report.cold+0x7c/0xd8
[ 402.824752] ? prog_array_map_poke_run+0xc2/0x34e
[ 402.824757] prog_array_map_poke_run+0xc2/0x34e
[ 402.824765] bpf_fd_array_map_update_elem+0x124/0x1a0
[...]

The elements concerned are walked as follows:

for (i = 0; i < elem->aux->size_poke_tab; i++) {
poke = &elem->aux->poke_tab[i];
[...]

The access to size_poke_tab is a 4 byte read, verified by checking offsets
in the KASAN dump:

[ 402.825004] The buggy address belongs to the object at ffff8881905a7800
which belongs to the cache kmalloc-1k of size 1024
[ 402.825008] The buggy address is located 320 bytes inside of
1024-byte region [ffff8881905a7800, ffff8881905a7c00)

The pahole output of bpf_prog_aux:

struct bpf_prog_aux {
[...]
/* --- cacheline 5 boundary (320 bytes) --- */
u32 size_poke_tab; /* 320 4 */
[...]

In general, subprograms do not necessarily manage their own data structures.
For example, BTF func_info and linfo are just pointers to the main program
structure. This allows reference counting and cleanup to be done on the latter
which simplifies their management a bit. The aux->poke_tab struct, however,
did not follow this logic. The initial proposed fix for this use-after-free
bug further embedded poke data tracking into the subprogram with proper
reference counting. However, Daniel and Alexei questioned why we were treating
these objects special; I agree, its unnecessary. The fix here removes the per
subprogram poke table allocation and map tracking and instead simply points
the aux->poke_tab pointer at the main programs poke table. This way, map
tracking is simplified to the main program and we do not need to manage them
per subprogram.

This also means, bpf_prog_free_deferred(), which unwinds the program reference
counting and kfrees objects, needs to ensure that we don't try to double free
the poke_tab when free'ing the subprog structures. This is easily solved by
NULL'ing the poke_tab pointer. The second detail is to ensure that per
subprogram JIT logic only does fixups on poke_tab[] entries it owns. To do
this, we add a pointer in the poke structure to point at the subprogram value
so JITs can easily check while walking the poke_tab structure if the current
entry belongs to the current program. The aux pointer is stable and therefore
suitable for such comparison. On the jit_subprogs() error path, we omit
cleaning up the poke->aux field because these are only ever referenced from
the JIT side, but on error we will never make it to the JIT, so its fine to
leave them dangling. Removing these pointers would complicate the error path
for no reason. However, we do need to untrack all poke descriptors from the
main program as otherwise they could race with the freeing of JIT memory from
the subprograms. Lastly, a748c6975dea3 ("bpf: propagate poke des
---truncated---

SUSE information

Overall state of this security issue: Resolved

This issue is currently rated as having moderate severity.

CVSS v3 Scores
  SUSE
Base Score 5.5
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality Impact None
Integrity Impact None
Availability Impact High
CVSSv3 Version 3.1
SUSE Bugzilla entry: 1224962 [RESOLVED / FIXED]

No SUSE Security Announcements cross referenced.


Status of this issue by product and package

Please note that this evaluation state might be work in progress, incomplete or outdated. Also information for service packs in the LTSS phase is only included for issues meeting the LTSS criteria. If in doubt, feel free to contact us for clarification. The updates are grouped by state of their lifecycle. SUSE product lifecycles are documented on the lifecycle page.

Product(s) Source package State
Products under general support and receiving all security fixes.
SUSE Linux Enterprise Desktop 15 SP5 kernel-default Already fixed
SUSE Linux Enterprise Desktop 15 SP5 kernel-source Already fixed
SUSE Linux Enterprise Desktop 15 SP6 kernel-default Already fixed
SUSE Linux Enterprise Desktop 15 SP6 kernel-source Already fixed
SUSE Linux Enterprise High Performance Computing 15 SP5 kernel-default Already fixed
SUSE Linux Enterprise High Performance Computing 15 SP5 kernel-source Already fixed
SUSE Linux Enterprise High Performance Computing 15 SP5 kernel-source-azure Already fixed
SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS kernel-source Already fixed
SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS kernel-source Already fixed
SUSE Linux Enterprise High Performance Computing 15 SP6 kernel-default Already fixed
SUSE Linux Enterprise High Performance Computing 15 SP6 kernel-source Already fixed
SUSE Linux Enterprise High Performance Computing 15 SP6 kernel-source-azure Already fixed
SUSE Linux Enterprise Micro 5.1 kernel-default Not affected
SUSE Linux Enterprise Micro 5.1 kernel-rt Not affected
SUSE Linux Enterprise Micro 5.1 kernel-source-rt Not affected
SUSE Linux Enterprise Micro 5.2 kernel-default Not affected
SUSE Linux Enterprise Micro 5.2 kernel-rt Not affected
SUSE Linux Enterprise Micro 5.2 kernel-source-rt Not affected
SUSE Linux Enterprise Micro 5.3 kernel-default Already fixed
SUSE Linux Enterprise Micro 5.3 kernel-rt Already fixed
SUSE Linux Enterprise Micro 5.3 kernel-source-rt Already fixed
SUSE Linux Enterprise Micro 5.4 kernel-default Already fixed
SUSE Linux Enterprise Micro 5.4 kernel-rt Already fixed
SUSE Linux Enterprise Micro 5.4 kernel-source-rt Already fixed
SUSE Linux Enterprise Micro 5.5 kernel-source-rt Already fixed
SUSE Linux Enterprise Module for Basesystem 15 SP5 kernel-default Already fixed
SUSE Linux Enterprise Module for Basesystem 15 SP5 kernel-source Already fixed
SUSE Linux Enterprise Module for Basesystem 15 SP6 kernel-default Already fixed
SUSE Linux Enterprise Module for Basesystem 15 SP6 kernel-source Already fixed
SUSE Linux Enterprise Module for Development Tools 15 SP5 kernel-default Already fixed
SUSE Linux Enterprise Module for Development Tools 15 SP5 kernel-source Already fixed
SUSE Linux Enterprise Module for Development Tools 15 SP6 kernel-default Already fixed
SUSE Linux Enterprise Module for Development Tools 15 SP6 kernel-source Already fixed
SUSE Linux Enterprise Module for Public Cloud 15 SP5 kernel-source-azure Already fixed
SUSE Linux Enterprise Module for Public Cloud 15 SP6 kernel-source-azure Already fixed
SUSE Linux Enterprise Real Time 15 SP5 kernel-source-rt Already fixed
SUSE Linux Enterprise Real Time 15 SP6 kernel-source-rt Already fixed
SUSE Linux Enterprise Server 15 SP5 kernel-default Already fixed
SUSE Linux Enterprise Server 15 SP5 kernel-source Already fixed
SUSE Linux Enterprise Server 15 SP5 kernel-source-azure Already fixed
SUSE Linux Enterprise Server 15 SP5-LTSS kernel-source Already fixed
SUSE Linux Enterprise Server 15 SP6 kernel-default Already fixed
SUSE Linux Enterprise Server 15 SP6 kernel-source Already fixed
SUSE Linux Enterprise Server 15 SP6 kernel-source-azure Already fixed
SUSE Linux Enterprise Server for SAP Applications 15 SP5 kernel-default Already fixed
SUSE Linux Enterprise Server for SAP Applications 15 SP5 kernel-source Already fixed
SUSE Linux Enterprise Server for SAP Applications 15 SP5 kernel-source-azure Already fixed
SUSE Linux Enterprise Server for SAP Applications 15 SP6 kernel-default Already fixed
SUSE Linux Enterprise Server for SAP Applications 15 SP6 kernel-source Already fixed
SUSE Linux Enterprise Server for SAP Applications 15 SP6 kernel-source-azure Already fixed
SUSE Manager Proxy 4.3 kernel-default Already fixed
SUSE Manager Proxy 4.3 kernel-source Already fixed
SUSE Manager Retail Branch Server 4.3 kernel-default Already fixed
SUSE Manager Retail Branch Server 4.3 kernel-source Already fixed
SUSE Manager Server 4.3 kernel-default Already fixed
SUSE Manager Server 4.3 kernel-source Already fixed
SUSE Real Time Module 15 SP5 kernel-source-rt Already fixed
SUSE Real Time Module 15 SP6 kernel-source-rt Already fixed
openSUSE Leap 15.5 kernel-default Already fixed
openSUSE Leap 15.5 kernel-source Already fixed
openSUSE Leap 15.5 kernel-source-azure Already fixed
openSUSE Leap 15.5 kernel-source-rt Already fixed
openSUSE Leap 15.6 kernel-default Already fixed
openSUSE Leap 15.6 kernel-source Already fixed
openSUSE Leap 15.6 kernel-source-azure Already fixed
openSUSE Leap 15.6 kernel-source-rt Already fixed
Products under Long Term Service Pack support and receiving important and critical security fixes.
SUSE Linux Enterprise Desktop 15 SP4 kernel-source Already fixed
SUSE Linux Enterprise High Performance Computing 12 SP5 kernel-default Not affected
SUSE Linux Enterprise High Performance Computing 12 SP5 kernel-source Not affected
SUSE Linux Enterprise High Performance Computing 12 SP5 kernel-source-azure Not affected
SUSE Linux Enterprise High Performance Computing 15 SP2 kernel-source Not affected
SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS kernel-source Not affected
SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS kernel-default Not affected
SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS kernel-source Not affected
SUSE Linux Enterprise High Performance Computing 15 SP3 kernel-source Not affected
SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS kernel-source Not affected
SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS kernel-default Not affected
SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS kernel-source Not affected
SUSE Linux Enterprise High Performance Computing 15 SP4 kernel-source Already fixed
SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS kernel-default Already fixed
SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS kernel-source Already fixed
SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS kernel-default Already fixed
SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS kernel-source Already fixed
SUSE Linux Enterprise Module for Basesystem 15 SP2 kernel-source Not affected
SUSE Linux Enterprise Module for Basesystem 15 SP3 kernel-source Not affected
SUSE Linux Enterprise Module for Basesystem 15 SP4 kernel-source Already fixed
SUSE Linux Enterprise Module for Development Tools 15 SP2 kernel-source Not affected
SUSE Linux Enterprise Module for Development Tools 15 SP3 kernel-source Not affected
SUSE Linux Enterprise Module for Development Tools 15 SP4 kernel-source Already fixed
SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE kernel-default Not affected
SUSE Linux Enterprise Server 11 SP4 LTSS EXTREME CORE kernel-source Not affected
SUSE Linux Enterprise Server 12 SP5 kernel-default Not affected
SUSE Linux Enterprise Server 12 SP5 kernel-source Not affected
SUSE Linux Enterprise Server 12 SP5 kernel-source-azure Not affected
SUSE Linux Enterprise Server 12 SP5-LTSS kernel-source Not affected
SUSE Linux Enterprise Server 12 SP5-LTSS kernel-source-azure Not affected
SUSE Linux Enterprise Server 15 SP2 kernel-source Not affected
SUSE Linux Enterprise Server 15 SP2-LTSS kernel-default Not affected
SUSE Linux Enterprise Server 15 SP2-LTSS kernel-source Not affected
SUSE Linux Enterprise Server 15 SP3 kernel-source Not affected
SUSE Linux Enterprise Server 15 SP3-LTSS kernel-default Not affected
SUSE Linux Enterprise Server 15 SP3-LTSS kernel-source Not affected
SUSE Linux Enterprise Server 15 SP4 kernel-source Already fixed
SUSE Linux Enterprise Server 15 SP4-LTSS kernel-default Already fixed
SUSE Linux Enterprise Server 15 SP4-LTSS kernel-source Already fixed
SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 kernel-source Not affected
SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 kernel-source-azure Not affected
SUSE Linux Enterprise Server for SAP Applications 12 SP5 kernel-default Not affected
SUSE Linux Enterprise Server for SAP Applications 12 SP5 kernel-source Not affected
SUSE Linux Enterprise Server for SAP Applications 12 SP5 kernel-source-azure Not affected
SUSE Linux Enterprise Server for SAP Applications 15 SP2 kernel-default Not affected
SUSE Linux Enterprise Server for SAP Applications 15 SP2 kernel-source Not affected
SUSE Linux Enterprise Server for SAP Applications 15 SP3 kernel-default Not affected
SUSE Linux Enterprise Server for SAP Applications 15 SP3 kernel-source Not affected
SUSE Linux Enterprise Server for SAP Applications 15 SP4 kernel-default Already fixed
SUSE Linux Enterprise Server for SAP Applications 15 SP4 kernel-source Already fixed
Products past their end of life and not receiving proactive updates anymore.
HPE Helion OpenStack 8 kernel-source Not affected
SUSE CaaS Platform 4.0 kernel-source Not affected
SUSE CaaS Platform Toolchain 3 kernel-source Not affected
SUSE Enterprise Storage 6 kernel-source Not affected
SUSE Enterprise Storage 7 kernel-source Not affected
SUSE Enterprise Storage 7.1 kernel-default Not affected
SUSE Enterprise Storage 7.1 kernel-source Not affected
SUSE Linux Enterprise Desktop 11 SP4 kernel-source Not affected
SUSE Linux Enterprise Desktop 12 SP3 kernel-source Not affected
SUSE Linux Enterprise Desktop 12 SP4 kernel-source Not affected
SUSE Linux Enterprise Desktop 15 kernel-source Not affected
SUSE Linux Enterprise Desktop 15 SP1 kernel-source Not affected
SUSE Linux Enterprise Desktop 15 SP2 kernel-source Not affected
SUSE Linux Enterprise Desktop 15 SP3 kernel-source Not affected
SUSE Linux Enterprise High Performance Computing 15 kernel-source Not affected
SUSE Linux Enterprise High Performance Computing 15 SP1 kernel-source Not affected
SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS kernel-source Not affected
SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS kernel-source Not affected
SUSE Linux Enterprise High Performance Computing 15-ESPOS kernel-source Not affected
SUSE Linux Enterprise High Performance Computing 15-LTSS kernel-source Not affected
SUSE Linux Enterprise Micro 5.0 kernel-default Not affected
SUSE Linux Enterprise Module for Basesystem 15 kernel-source Not affected
SUSE Linux Enterprise Module for Basesystem 15 SP1 kernel-source Not affected
SUSE Linux Enterprise Module for Development Tools 15 kernel-source Not affected
SUSE Linux Enterprise Module for Development Tools 15 SP1 kernel-source Not affected
SUSE Linux Enterprise Real Time 12 SP5 kernel-source-rt Not affected
SUSE Linux Enterprise Real Time 15 SP2 kernel-source Not affected
SUSE Linux Enterprise Real Time 15 SP3 kernel-source Not affected
SUSE Linux Enterprise Real Time 15 SP3 kernel-source-rt Not affected
SUSE Linux Enterprise Real Time 15 SP4 kernel-source Already fixed
SUSE Linux Enterprise Real Time 15 SP4 kernel-source-rt Already fixed
SUSE Linux Enterprise Server 11 SP4 kernel-source Not affected
SUSE Linux Enterprise Server 11 SP4 LTSS kernel-default Not affected
SUSE Linux Enterprise Server 11 SP4 LTSS kernel-source Not affected
SUSE Linux Enterprise Server 11 SP4-LTSS kernel-source Not affected
SUSE Linux Enterprise Server 12 SP3 kernel-source Not affected
SUSE Linux Enterprise Server 12 SP3-BCL kernel-source Not affected
SUSE Linux Enterprise Server 12 SP3-ESPOS kernel-source Not affected
SUSE Linux Enterprise Server 12 SP3-LTSS kernel-source Not affected
SUSE Linux Enterprise Server 12 SP4 kernel-source Not affected
SUSE Linux Enterprise Server 12 SP4-ESPOS kernel-source Not affected
SUSE Linux Enterprise Server 12 SP4-LTSS kernel-default Not affected
SUSE Linux Enterprise Server 12 SP4-LTSS kernel-source Not affected
SUSE Linux Enterprise Server 15 kernel-source Not affected
SUSE Linux Enterprise Server 15 SP1 kernel-source Not affected
SUSE Linux Enterprise Server 15 SP1-BCL kernel-source Not affected
SUSE Linux Enterprise Server 15 SP1-LTSS kernel-default Not affected
SUSE Linux Enterprise Server 15 SP1-LTSS kernel-source Not affected
SUSE Linux Enterprise Server 15 SP2-BCL kernel-source Not affected
SUSE Linux Enterprise Server 15 SP3-BCL kernel-source Not affected
SUSE Linux Enterprise Server 15-LTSS kernel-default Not affected
SUSE Linux Enterprise Server 15-LTSS kernel-source Not affected
SUSE Linux Enterprise Server for SAP Applications 12 SP3 kernel-source Not affected
SUSE Linux Enterprise Server for SAP Applications 12 SP4 kernel-default Not affected
SUSE Linux Enterprise Server for SAP Applications 12 SP4 kernel-source Not affected
SUSE Linux Enterprise Server for SAP Applications 15 kernel-source Not affected
SUSE Linux Enterprise Server for SAP Applications 15 SP1 kernel-source Not affected
SUSE Manager Proxy 4.0 kernel-source Not affected
SUSE Manager Proxy 4.1 kernel-source Not affected
SUSE Manager Proxy 4.2 kernel-source Not affected
SUSE Manager Retail Branch Server 4.0 kernel-source Not affected
SUSE Manager Retail Branch Server 4.1 kernel-source Not affected
SUSE Manager Retail Branch Server 4.2 kernel-source Not affected
SUSE Manager Server 4.0 kernel-source Not affected
SUSE Manager Server 4.1 kernel-source Not affected
SUSE Manager Server 4.2 kernel-source Not affected
SUSE OpenStack Cloud 8 kernel-source Not affected
SUSE OpenStack Cloud 9 kernel-default Not affected
SUSE OpenStack Cloud 9 kernel-source Not affected
SUSE OpenStack Cloud Crowbar 8 kernel-source Not affected
SUSE OpenStack Cloud Crowbar 9 kernel-default Not affected
SUSE OpenStack Cloud Crowbar 9 kernel-source Not affected
SUSE Real Time Module 15 SP3 kernel-source-rt Not affected
SUSE Real Time Module 15 SP4 kernel-source-rt Already fixed
openSUSE Leap 15.3 kernel-source Not affected
openSUSE Leap 15.3 kernel-source-rt Not affected
openSUSE Leap 15.4 kernel-source Already fixed
openSUSE Leap 15.4 kernel-source-azure Unsupported
openSUSE Leap 15.4 kernel-source-rt Already fixed


SUSE Timeline for this CVE

CVE page created: Tue May 21 18:00:34 2024
CVE page last modified: Fri Dec 20 23:48:35 2024