CVE-2023-52761

commit 31da94c25aea ("riscv: add VMAPSTACK overflow detection") added support for CONFIGVMAP_STACK. If overflow is detected, CPU switches to shadow_stack temporarily before switching finally to per-cpu overflow_stack.

If two CPUs/harts are racing and end up in over flowing kernel stack, one or both will end up corrupting each other state because shadow_stack is not per-cpu. This patch optimizes per-cpu overflow stack switch by directly picking per-cpu overflow_stack and gets rid of shadow_stack.

Following are the changes in this patch

Defines an asm macro to obtain per-cpu symbols in destination register.
In entry.S, when overflow is detected, per-cpu overflow stack is located using per-cpu asm macro. Computing per-cpu symbol requires a temporary register. x31 is saved away into CSRSCRATCH (CSRSCRATCH is anyways zero since we're in kernel).

Please see Links for additional relevant disccussion and alternative solution.

Tested by echo EXHAUST_STACK > /sys/kernel/debug/provoke-crash/DIRECT Kernel crash log below

Insufficient stack space to handle exception!/debug/provoke-crash/DIRECT Task stack: [0xff20000010a98000..0xff20000010a9c000] Overflow stack: [0xff600001f7d98370..0xff600001f7d99370] CPU: 1 PID: 205 Comm: bash Not tainted 6.1.0-rc2-00001-g328a1f96f7b9 #34 Hardware name: riscv-virtio,qemu (DT) epc : _memset+0x60/0xfc ra : recursiveloop+0x48/0xc6 [lkdtm] epc : ffffffff808de0e4 ra : ffffffff0163a752 sp : ff20000010a97e80 gp : ffffffff815c0330 tp : ff600000820ea280 t0 : ff20000010a97e88 t1 : 000000000000002e t2 : 3233206874706564 s0 : ff20000010a982b0 s1 : 0000000000000012 a0 : ff20000010a97e88 a1 : 0000000000000000 a2 : 0000000000000400 a3 : ff20000010a98288 a4 : 0000000000000000 a5 : 0000000000000000 a6 : fffffffffffe43f0 a7 : 00007fffffffffff s2 : ff20000010a97e88 s3 : ffffffff01644680 s4 : ff20000010a9be90 s5 : ff600000842ba6c0 s6 : 00aaaaaac29e42b0 s7 : 00fffffff0aa3684 s8 : 00aaaaaac2978040 s9 : 0000000000000065 s10: 00ffffff8a7cad10 s11: 00ffffff8a76a4e0 t3 : ffffffff815dbaf4 t4 : ffffffff815dbaf4 t5 : ffffffff815dbab8 t6 : ff20000010a9bb48 status: 0000000200000120 badaddr: ff20000010a97e88 cause: 000000000000000f Kernel panic - not syncing: Kernel stack overflow CPU: 1 PID: 205 Comm: bash Not tainted 6.1.0-rc2-00001-g328a1f96f7b9 #34 Hardware name: riscv-virtio,qemu (DT) Call Trace: [<ffffffff80006754>] dumpbacktrace+0x30/0x38 [<ffffffff808de798>] showstack+0x40/0x4c [<ffffffff808ea2a8>] dumpstacklvl+0x44/0x5c [<ffffffff808ea2d8>] dumpstack+0x18/0x20 [<ffffffff808dec06>] panic+0x126/0x2fe [<ffffffff800065ea>] walkstackframe+0x0/0xf0 [<ffffffff0163a752>] recursive_loop+0x48/0xc6 [lkdtm] SMP: stopping secondary CPUs ---[ end Kernel panic - not syncing: Kernel stack overflow ]---

Database specific

{
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/52xxx/CVE-2023-52761.json"
}

References

Affected packages

Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Affected ranges

Type: GIT
Repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Events: Introduced

76d2a0493a17d4c8ecc781366850c3c4f8e1a446

Fixed

1493baaf09e3c1899959c8a107cd1207e16d1788

Fixed

eff53aea3855f71992c043cebb1c00988c17ee20

Fixed

be97d0db5f44c0674480cb79ac6f5b0529b84c76

Affected versions

v4.*

v4.14

v4.14-rc3

v4.14-rc4

v4.14-rc5

v4.14-rc6

v4.14-rc7

v4.14-rc8

v4.15

v4.15-rc1

v4.15-rc2

v4.15-rc3

v4.15-rc4

v4.15-rc5

v4.15-rc6

v4.15-rc7

v4.15-rc8

v4.15-rc9

v4.16

v4.16-rc1

v4.16-rc2

v4.16-rc3

v4.16-rc4

v4.16-rc5

v4.16-rc6

v4.16-rc7

v4.17

v4.17-rc1

v4.17-rc2

v4.17-rc3

v4.17-rc4

v4.17-rc5

v4.17-rc6

v4.17-rc7

v4.18

v4.18-rc1

v4.18-rc2

v4.18-rc3

v4.18-rc4

v4.18-rc5

v4.18-rc6

v4.18-rc7

v4.18-rc8

v4.19

v4.19-rc1

v4.19-rc2

v4.19-rc3

v4.19-rc4

v4.19-rc5

v4.19-rc6

v4.19-rc7

v4.19-rc8

v4.20

v4.20-rc1

v4.20-rc2

v4.20-rc3

v4.20-rc4

v4.20-rc5

v4.20-rc6

v4.20-rc7

v5.*

v5.0

v5.0-rc1

v5.0-rc2

v5.0-rc3

v5.0-rc4

v5.0-rc5

v5.0-rc6

v5.0-rc7

v5.0-rc8

v5.1

v5.1-rc1

v5.1-rc2

v5.1-rc3

v5.1-rc4

v5.1-rc5

v5.1-rc6

v5.1-rc7

v5.10

v5.10-rc1

v5.10-rc2

v5.10-rc3

v5.10-rc4

v5.10-rc5

v5.10-rc6

v5.10-rc7

v5.11

v5.11-rc1

v5.11-rc2

v5.11-rc3

v5.11-rc4

v5.11-rc5

v5.11-rc6

v5.11-rc7

v5.12

v5.12-rc1

v5.12-rc1-dontuse

v5.12-rc2

v5.12-rc3

v5.12-rc4

v5.12-rc5

v5.12-rc6

v5.12-rc7

v5.12-rc8

v5.13

v5.13-rc1

v5.13-rc2

v5.13-rc3

v5.13-rc4

v5.13-rc5

v5.13-rc6

v5.13-rc7

v5.14

v5.14-rc1

v5.14-rc2

v5.14-rc3

v5.14-rc4

v5.14-rc5

v5.14-rc6

v5.14-rc7

v5.15

v5.15-rc1

v5.15-rc2

v5.15-rc3

v5.15-rc4

v5.15-rc5

v5.15-rc6

v5.15-rc7

v5.16

v5.16-rc1

v5.16-rc2

v5.16-rc3

v5.16-rc4

v5.16-rc5

v5.16-rc6

v5.16-rc7

v5.16-rc8

v5.17

v5.17-rc1

v5.17-rc2

v5.17-rc3

v5.17-rc4

v5.17-rc5

v5.17-rc6

v5.17-rc7

v5.17-rc8

v5.18

v5.18-rc1

v5.18-rc2

v5.18-rc3

v5.18-rc4

v5.18-rc5

v5.18-rc6

v5.18-rc7

v5.19

v5.19-rc1

v5.19-rc2

v5.19-rc3

v5.19-rc4

v5.19-rc5

v5.19-rc6

v5.19-rc7

v5.19-rc8

v5.2

v5.2-rc1

v5.2-rc2

v5.2-rc3

v5.2-rc4

v5.2-rc5

v5.2-rc6

v5.2-rc7

v5.3

v5.3-rc1

v5.3-rc2

v5.3-rc3

v5.3-rc4

v5.3-rc5

v5.3-rc6

v5.3-rc7

v5.3-rc8

v5.4

v5.4-rc1

v5.4-rc2

v5.4-rc3

v5.4-rc4

v5.4-rc5

v5.4-rc6

v5.4-rc7

v5.4-rc8

v5.5

v5.5-rc1

v5.5-rc2

v5.5-rc3

v5.5-rc4

v5.5-rc5

v5.5-rc6

v5.5-rc7

v5.6

v5.6-rc1

v5.6-rc2

v5.6-rc3

v5.6-rc4

v5.6-rc5

v5.6-rc6

v5.6-rc7

v5.7

v5.7-rc1

v5.7-rc2

v5.7-rc3

v5.7-rc4

v5.7-rc5

v5.7-rc6

v5.7-rc7

v5.8

v5.8-rc1

v5.8-rc2

v5.8-rc3

v5.8-rc4

v5.8-rc5

v5.8-rc6

v5.8-rc7

v5.9

v5.9-rc1

v5.9-rc2

v5.9-rc3

v5.9-rc4

v5.9-rc5

v5.9-rc6

v5.9-rc7

v5.9-rc8

v6.*

v6.0

v6.0-rc1

v6.0-rc2

v6.0-rc3

v6.0-rc4

v6.0-rc5

v6.0-rc6

v6.0-rc7

v6.1

v6.1-rc1

v6.1-rc2

v6.1-rc3

v6.1-rc4

v6.1-rc5

v6.1-rc6

v6.1-rc7

v6.1-rc8

v6.2

v6.2-rc1

v6.2-rc2

v6.2-rc3

v6.2-rc4

v6.2-rc5

v6.2-rc6

v6.2-rc7

v6.2-rc8

v6.3

v6.3-rc1

v6.3-rc2

v6.3-rc3

v6.3-rc4

v6.3-rc5

v6.3-rc6

v6.3-rc7

v6.4

v6.4-rc1

v6.4-rc2

v6.4-rc3

v6.4-rc4

v6.4-rc5

v6.4-rc6

v6.4-rc7

v6.5

v6.5-rc1

v6.5-rc2

v6.5-rc3

v6.5-rc4

v6.5-rc5

v6.5-rc6

v6.5-rc7

v6.5.1

v6.5.10

v6.5.11

v6.5.12

v6.5.2

v6.5.3

v6.5.4

v6.5.5

v6.5.6

v6.5.7

v6.5.8

v6.5.9

v6.6

v6.6-rc1

v6.6-rc2

v6.6-rc3

v6.6-rc4

v6.6-rc5

v6.6-rc6

v6.6-rc7

v6.6.1

v6.6.2

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-52761.json"

vanir_signatures

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Git / github.com/gregkh/linux