DEBIAN-CVE-2024-35871

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Source
https://security-tracker.debian.org/tracker/CVE-2024-35871
Import Source
https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2024-35871.json
JSON Data
https://api.osv.dev/v1/vulns/DEBIAN-CVE-2024-35871
Upstream
Published
2024-05-19T09:15:08Z
Modified
2025-09-30T05:18:23.847710Z
Summary
[none]
Details

In the Linux kernel, the following vulnerability has been resolved: riscv: process: Fix kernel gp leakage childregs represents the registers which are active for the new thread in user context. For a kernel thread, childregs->gp is never used since the kernel gp is not touched by switchto. For a user mode helper, the gp value can be observed in user space after execve or possibly by other means. [From the email thread] The /* Kernel thread */ comment is somewhat inaccurate in that it is also used for usermodehelper threads, which exec a user process, e.g. /sbin/init or when /proc/sys/kernel/corepattern is a pipe. Such threads do not have PFKTHREAD set and are valid targets for ptrace etc. even before they exec. childregs is the *user* context during syscall execution and it is observable from userspace in at least five ways: 1. kernelexecve does not currently clear integer registers, so the starting register state for PID 1 and other user processes started by the kernel has sp = user stack, gp = kernel _globalpointer$, all other integer registers zeroed by the memset in the patch comment. This is a bug in its own right, but I'm unwilling to bet that it is the only way to exploit the issue addressed by this patch. 2. ptrace(PTRACEGETREGSET): you can PTRACEATTACH to a usermodehelper thread before it execs, but ptrace requires SIGSTOP to be delivered which can only happen at user/kernel boundaries. 3. /proc//task//syscall: this is perfectly happy to read ptregs for usermodehelpers before the exec completes, but gp is not one of the registers it returns. 4. PERFSAMPLEREGSUSER: LOCKDOWNPERF normally prevents access to kernel addresses via PERFSAMPLEREGSINTR, but due to this bug kernel addresses are also exposed via PERFSAMPLEREGSUSER which is permitted under LOCKDOWNPERF. I have not attempted to write exploit code. 5. Much of the tracing infrastructure allows access to user registers. I have not attempted to determine which forms of tracing allow access to user registers without already allowing access to kernel registers.

References

Affected packages

Debian:11 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
5.10.216-1

Affected versions

5.*

5.10.46-4
5.10.46-5
5.10.70-1~bpo10+1
5.10.70-1
5.10.84-1
5.10.92-1~bpo10+1
5.10.92-1
5.10.92-2
5.10.103-1~bpo10+1
5.10.103-1
5.10.106-1
5.10.113-1
5.10.120-1~bpo10+1
5.10.120-1
5.10.127-1
5.10.127-2~bpo10+1
5.10.127-2
5.10.136-1
5.10.140-1
5.10.148-1
5.10.149-1
5.10.149-2
5.10.158-1
5.10.158-2
5.10.162-1
5.10.178-1
5.10.178-2
5.10.178-3
5.10.179-1
5.10.179-2
5.10.179-3
5.10.179-4
5.10.179-5
5.10.191-1
5.10.197-1
5.10.205-1
5.10.205-2
5.10.209-1
5.10.209-2

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Debian:12 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
6.1.85-1

Affected versions

6.*

6.1.27-1
6.1.37-1
6.1.38-1
6.1.38-2~bpo11+1
6.1.38-2
6.1.38-3
6.1.38-4~bpo11+1
6.1.38-4
6.1.52-1
6.1.55-1~bpo11+1
6.1.55-1
6.1.64-1
6.1.66-1
6.1.67-1
6.1.69-1~bpo11+1
6.1.69-1
6.1.76-1~bpo11+1
6.1.76-1
6.1.82-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Debian:13 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
6.8.9-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}

Debian:14 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
6.8.9-1

Ecosystem specific 

{
    "urgency": "not yet assigned"
}