CVE-2023-52828: 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…

PriorityP419medium5.5CVSS 3.1

AVLACLPRLUINSUCNINAH

EPSS

0.25%

15.9th percentile

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.

Affected

17 ranges

Vendor	Product	Version range	Fixed in
debian	linux	< linux 6.1.64-1 (bookworm)	linux 6.1.64-1 (bookworm)
linux	linux	—	—
linux	linux	>= 74451e66d516c55e309e8d89a4a1e7596e46aacd < 6058e4829696412457729a00734969acc6fd1d18	6058e4829696412457729a00734969acc6fd1d18
linux	linux	>= 74451e66d516c55e309e8d89a4a1e7596e46aacd < cf353904a82873e952633fcac4385c2fcd3a46e1	cf353904a82873e952633fcac4385c2fcd3a46e1
linux	linux	>= 74451e66d516c55e309e8d89a4a1e7596e46aacd < aa42a7cb92647786719fe9608685da345883878f	aa42a7cb92647786719fe9608685da345883878f
linux	linux	>= 74451e66d516c55e309e8d89a4a1e7596e46aacd < 327b92e8cb527ae097961ffd1610c720481947f5	327b92e8cb527ae097961ffd1610c720481947f5
linux	linux	>= 74451e66d516c55e309e8d89a4a1e7596e46aacd < 821a7e4143af115b840ec199eb179537e18af922	821a7e4143af115b840ec199eb179537e18af922
linux	linux	>= 74451e66d516c55e309e8d89a4a1e7596e46aacd < 66d9111f3517f85ef2af0337ece02683ce0faf21	66d9111f3517f85ef2af0337ece02683ce0faf21
linux	linux_kernel	< 5.10.202	5.10.202
linux	linux_kernel	>= 0 < 5.10.205-1	5.10.205-1
linux	linux_kernel	>= 0 < 6.1.64-1	6.1.64-1
linux	linux_kernel	>= 0 < 6.6.8-1	6.6.8-1
linux	linux_kernel	>= 0 < 6.6.8-1	6.6.8-1
linux	linux_kernel	>= 5.11 < 5.15.140	5.15.140
linux	linux_kernel	>= 5.16 < 6.1.64	6.1.64
linux	linux_kernel	>= 6.2 < 6.5.13	6.5.13
linux	linux_kernel	>= 6.6 < 6.6.3	6.6.3

CVSS provenance

nvdv3.15.5MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

osv5.5MEDIUM

vendor_debian5.5MEDIUM

vendor_redhat5.5MEDIUM

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