Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix linked reg delta tracking when src_reg == dst_reg Consider the case of rX += rX where src_reg and dst_reg are pointers to the same bpf_reg_state in adjust_reg_min_max_vals(). The latter first modifies the dst_reg in-place, and later in the delta tracking, the subsequent is_reg_const(src_reg)/reg_const_value(src_reg) reads the post-{add,sub} value instead of the original source. This is problematic since it sets an incorrect delta, which sync_linked_regs() then propagates to linked registers, thus creating a verifier-vs-runtime mismatch. Fix it by just skipping this corner case.
CVSS breakdown
CVSS 3.1
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Affected products
- Linux / Linux98d7ca374ba4b39e7535613d40e159f09ca14da2 – d88e8e4a3b52bd5b2ff3eceba4b29d1b5506d066
- Linux / Linux98d7ca374ba4b39e7535613d40e159f09ca14da2 – cc86a8b0a1c54d2bccf6f68cf49b82dea91b84de
- Linux / Linux98d7ca374ba4b39e7535613d40e159f09ca14da2 – d7f14173c0d5866c3cae759dee560ad1bed10d2e
- Linux / Linux6.11 – 6.11
- Linux / Linux0 – 6.11
- Linux / Linux6.18.33 – 6.18.*
- Linux / Linux7.0.10 – 7.0.*
- Linux / Linux7.1 – *