CVE-2023-52828
What it is
In the Linux kernel, the following vulnerability has been resolved: bpf: Detect IP == ksym.end as part of BPF program Now that bpf_throw kfunc is the first such call instruction that has noreturn semantics within the verifier, this also kicks in dead code elimination in unprecedented ways. For one, any instruction following a bpf_throw call will never be marked as seen. Moreover, if a callchain ends up throwing, any instructions after the call instruction to the eventually throwing subprog in callers will also never be marked as seen. The tempting way to fix this would be to emit extra 'int3' instructions which bump the jited_len of a program, and ensure that during runtime when a program throws, we can discover its boundaries even if the call instruction to bpf_throw (or to subprogs that always throw) is emitted as the final instruction in the program. An example of such a program would be this: do_something(): ... r0 = 0 exit foo(): r1 = 0 call bpf_throw r0 = 0 exit bar(cond): if r1 != 0 goto pc+2 call do_something exit call foo r0 = 0 // Never seen by verifier exit // main(ctx): r1 = ... call bar r0 = 0 exit Here, if we do end up throwing, the stacktrace would be the following: bpf_throw foo bar main In bar, the final instruction emitted will be the call to foo, as such, the return address will be the subsequent instruction (which the JIT emits as int3 on x86). This will end up lying outside the jited_len of the program, thus, when unwinding, we will fail to discover the return address as belonging to any program and end up in a panic due to the unreliable stack unwinding of BPF programs that we never expect. To remedy this case, make bpf_prog_ksym_find treat IP == ksym.end as part of the BPF program, so that is_bpf_text_address returns true when such a case occurs, and we are able to unwind reliably when the final instruction ends up being a call instruction.
At a glance
- Exploitability
- Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.
- Exploit odds
- 0.2% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.2% in the next 30 days (EPSS).
- Severity: 5.5 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.2% · EPSS, next 30 days
- Record status
- Analyzed
Affected
- Linux Kernel < 5.10.202
- Linux Kernel < 5.15.140
- Linux Kernel < 6.1.64
- Linux Kernel < 6.5.13
- Linux Kernel < 6.6.3
Attack profile CVSS 3.1 · 5.5
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2023-52828.md and follow it. Check whether this project is affected by CVE-2023-52828. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://git.kernel.org/stable/c/327b92e8cb527ae097961ffd1610c720481947f5
- https://git.kernel.org/stable/c/6058e4829696412457729a00734969acc6fd1d18
- https://git.kernel.org/stable/c/66d9111f3517f85ef2af0337ece02683ce0faf21
- https://git.kernel.org/stable/c/821a7e4143af115b840ec199eb179537e18af922
- https://git.kernel.org/stable/c/aa42a7cb92647786719fe9608685da345883878f
- https://git.kernel.org/stable/c/cf353904a82873e952633fcac4385c2fcd3a46e1
- https://git.kernel.org/stable/c/327b92e8cb527ae097961ffd1610c720481947f5
- https://git.kernel.org/stable/c/6058e4829696412457729a00734969acc6fd1d18
- https://git.kernel.org/stable/c/66d9111f3517f85ef2af0337ece02683ce0faf21
- https://git.kernel.org/stable/c/821a7e4143af115b840ec199eb179537e18af922
References
- https://git.kernel.org/stable/c/327b92e8cb527ae097961ffd1610c720481947f5
- https://git.kernel.org/stable/c/6058e4829696412457729a00734969acc6fd1d18
- https://git.kernel.org/stable/c/66d9111f3517f85ef2af0337ece02683ce0faf21
- https://git.kernel.org/stable/c/821a7e4143af115b840ec199eb179537e18af922
- https://git.kernel.org/stable/c/aa42a7cb92647786719fe9608685da345883878f
- https://git.kernel.org/stable/c/cf353904a82873e952633fcac4385c2fcd3a46e1
- https://git.kernel.org/stable/c/327b92e8cb527ae097961ffd1610c720481947f5
- https://git.kernel.org/stable/c/6058e4829696412457729a00734969acc6fd1d18
- https://git.kernel.org/stable/c/66d9111f3517f85ef2af0337ece02683ce0faf21
- https://git.kernel.org/stable/c/821a7e4143af115b840ec199eb179537e18af922
- https://git.kernel.org/stable/c/aa42a7cb92647786719fe9608685da345883878f
- https://git.kernel.org/stable/c/cf353904a82873e952633fcac4385c2fcd3a46e1