UBUNTU-CVE-2024-50072
In the Linux kernel, the following vulnerability has been resolved: x86/bugs: Use code segment selector for VERW operand Robert Gill reported below #GP in 32-bit mode when dosemu software was executing vm86() system call: general protection fault: 0000 [#1] PREEMPT SMP CPU: 4 PID: 4610 Comm: dosemu.bin Not tainted 6.6.21-gentoo-x86 #1 Hardware name: Dell Inc. PowerEdge 1950/0H723K, BIOS 2.7.0 10/30/2010 EIP: restore_all_switch_stack+0xbe/0xcf EAX: 00000000 EBX: 00000000 ECX: 00000000 EDX: 00000000 ESI: 00000000 EDI: 00000000 EBP: 00000000 ESP: ff8affdc DS: 0000 ES: 0000 FS: 0000 GS: 0033 SS: 0068 EFLAGS: 00010046 CR0: 80050033 CR2: 00c2101c CR3: 04b6d000 CR4: 000406d0 Call Trace: show_regs+0x70/0x78 die_addr+0x29/0x70 exc_general_protection+0x13c/0x348 exc_bounds+0x98/0x98 handle_exception+0x14d/0x14d exc_bounds+0x98/0x98 restore_all_switch_stack+0xbe/0xcf exc_bounds+0x98/0x98 restore_all_switch_stack+0xbe/0xcf This only happens in 32-bit mode when VERW based mitigations like MDS/RFDS are enabled. This is because segment registers with an arbitrary user value can result in #GP when executing VERW. Intel SDM vol. 2C documents the following behavior for VERW instruction: #GP(0) - If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit. CLEAR_CPU_BUFFERS macro executes VERW instruction before returning to user space. Use %cs selector to reference VERW operand. This ensures VERW will not #GP for an arbitrary user %ds. [ mingo: Fixed the SOB chain. ]
02 / AFFECTED SOFTWARE
Affected packages
59 explicit affected versions
14 explicit affected versions
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10 explicit affected versions
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1 explicit affected versions
45 explicit affected versions
37 explicit affected versions
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60 explicit affected versions
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14 explicit affected versions
8 explicit affected versions
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38 explicit affected versions
1 explicit affected versions
51 explicit affected versions
13 explicit affected versions
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10 explicit affected versions
10 explicit affected versions
58 explicit affected versions
13 explicit affected versions
11 explicit affected versions
1 explicit affected versions
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21 explicit affected versions
59 explicit affected versions
6 explicit affected versions
13 explicit affected versions
12 explicit affected versions
24 explicit affected versions
7 explicit affected versions
14 explicit affected versions
60 explicit affected versions
18 explicit affected versions
34 explicit affected versions
12 explicit affected versions
26 explicit affected versions
1 explicit affected versions
41 explicit affected versions
60 explicit affected versions
67 explicit affected versions
23 explicit affected versions
7 explicit affected versions
14 explicit affected versions
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14 explicit affected versions
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33 explicit affected versions
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19 explicit affected versions
51 explicit affected versions
18 explicit affected versions
34 explicit affected versions
3 explicit affected versions
23 explicit affected versions
23 explicit affected versions
26 explicit affected versions
19 explicit affected versions
12 explicit affected versions
13 explicit affected versions
15 explicit affected versions
44 explicit affected versions
4 explicit affected versions
4 explicit affected versions
16 explicit affected versions
12 explicit affected versions
9 explicit affected versions
12 explicit affected versions
52 explicit affected versions
7 explicit affected versions
13 explicit affected versions
14 explicit affected versions
22 explicit affected versions
7 explicit affected versions
19 explicit affected versions
50 explicit affected versions
13 explicit affected versions
7 explicit affected versions
10 explicit affected versions
14 explicit affected versions
18 explicit affected versions
3 explicit affected versions
16 explicit affected versions
43 explicit affected versions
24 explicit affected versions
20 explicit affected versions
19 explicit affected versions
11 explicit affected versions
12 explicit affected versions
47 explicit affected versions
15 explicit affected versions
64 explicit affected versions
35 explicit affected versions
12 explicit affected versions
13 explicit affected versions
6 explicit affected versions
12 explicit affected versions
1 explicit affected versions
50 explicit affected versions
11 explicit affected versions
12 explicit affected versions
58 explicit affected versions
27 explicit affected versions
12 explicit affected versions
7 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: x86/bugs: Use code segment selector for VERW operand Robert Gill reported below #GP in 32-bit mode when dosemu software was executing vm86() system call: general protection fault: 0000 [#1] PREEMPT SMP CPU: 4 PID: 4610 Comm: dosemu.bin Not tainted 6.6.21-gentoo-x86 #1 Hardware name: Dell Inc. PowerEdge 1950/0H723K, BIOS 2.7.0 10/30/2010 EIP: restore_all_switch_stack+0xbe/0xcf EAX: 00000000 EBX: 00000000 ECX: 00000000 EDX: 00000000 ESI: 00000000 EDI: 00000000 EBP: 00000000 ESP: ff8affdc DS: 0000 ES: 0000 FS: 0000 GS: 0033 SS: 0068 EFLAGS: 00010046 CR0: 80050033 CR2: 00c2101c CR3: 04b6d000 CR4: 000406d0 Call Trace: show_regs+0x70/0x78 die_addr+0x29/0x70 exc_general_protection+0x13c/0x348 exc_bounds+0x98/0x98 handle_exception+0x14d/0x14d exc_bounds+0x98/0x98 restore_all_switch_stack+0xbe/0xcf exc_bounds+0x98/0x98 restore_all_switch_stack+0xbe/0xcf This only happens in 32-bit mode when VERW based mitigations like MDS/RFDS are enabled. This is because segment registers with an arbitrary user value can result in #GP when executing VERW. Intel SDM vol. 2C documents the following behavior for VERW instruction: #GP(0) - If a memory operand effective address is outside the CS, DS, ES, FS, or GS segment limit. CLEAR_CPU_BUFFERS macro executes VERW instruction before returning to user space. Use %cs selector to reference VERW operand. This ensures VERW will not #GP for an arbitrary user %ds. [ mingo: Fixed the SOB chain. ]
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/e4d2102018542e3ae5e297bc6e229303abff8a0f
- https://git.kernel.org/stable/c/481b477ab63c7245715a3e57ba79eb87c2dc0d02
- https://git.kernel.org/stable/c/bc576fbaf82deded606e69a00efe9752136bf91d
- https://git.kernel.org/stable/c/e4d2102018542e3ae5e297bc6e229303abff8a0f
- https://ubuntu.com/security/CVE-2024-50072
- https://ubuntu.com/security/notices/USN-7276-1
- https://ubuntu.com/security/notices/USN-7277-1
- https://ubuntu.com/security/notices/USN-7288-1
- https://ubuntu.com/security/notices/USN-7288-2
- https://ubuntu.com/security/notices/USN-7289-1
- https://ubuntu.com/security/notices/USN-7289-2
- https://ubuntu.com/security/notices/USN-7289-3
- https://ubuntu.com/security/notices/USN-7289-4
- https://ubuntu.com/security/notices/USN-7291-1
- https://ubuntu.com/security/notices/USN-7305-1
- https://ubuntu.com/security/notices/USN-7308-1
- https://ubuntu.com/security/notices/USN-7310-1
- https://ubuntu.com/security/notices/USN-7331-1
- https://ubuntu.com/security/notices/USN-7383-1
- https://ubuntu.com/security/notices/USN-7383-2
- https://ubuntu.com/security/notices/USN-7384-1
- https://ubuntu.com/security/notices/USN-7384-2
- https://ubuntu.com/security/notices/USN-7385-1
- https://ubuntu.com/security/notices/USN-7386-1
- https://ubuntu.com/security/notices/USN-7388-1
- https://ubuntu.com/security/notices/USN-7389-1
- https://ubuntu.com/security/notices/USN-7390-1
- https://ubuntu.com/security/notices/USN-7403-1
- https://ubuntu.com/security/notices/USN-7451-1
- https://ubuntu.com/security/notices/USN-7458-1
- https://ubuntu.com/security/notices/USN-7468-1
- https://ubuntu.com/security/notices/USN-7523-1
- https://ubuntu.com/security/notices/USN-7524-1
- https://www.cve.org/CVERecord?id=CVE-2024-50072