Affected: Alpaquita:stream: linux-lts

In the Linux kernel, the following vulnerability has been resolved:

bpf, riscv: Fix extable handling for arena load_acquire

emit_atomic_ld_st() returns 1 to have build_body() skip the zext after a sub-word load_acquire. The caller does "ret = ret ?: add_exception_handler(...)", which skips add_exception_handler() on any non-zero ret, so the extable entry is missing and a faulting PROBE_ATOMIC load_acquire oopses.

REG_DONT_CLEAR_MARKER leaves rd stale on fault, and the verifier still thinks the load overwrote it, so a program can leak it through a map.

Check ret >= 0 before calling add_exception_handler(), and pass rd for LOAD_ACQ so the fault zeroes rd like a PROBE_MEM load. Return ret unchanged for the zext skip.

In the Linux kernel, the following vulnerability has been resolved:

bpf, riscv: Fix extable handling for arena load_acquire

emit_atomic_ld_st() returns 1 to have build_body() skip the zext after a sub-word load_acquire. The caller does "ret = ret ?: add_exception_handler(...)", which skips add_exception_handler() on any non-zero ret, so the extable entry is missing and a faulting PROBE_ATOMIC load_acquire oopses.

REG_DONT_CLEAR_MARKER leaves rd stale on fault, and the verifier still thinks the load overwrote it, so a program can leak it through a map.

Check ret >= 0 before calling add_exception_handler(), and pass rd for LOAD_ACQ so the fault zeroes rd like a PROBE_MEM load. Return ret unchanged for the zext skip.

kernel-devel-7.2.8-1.1 on GA media

Affected: Ubuntu:16.04:LTS: linux-hwe-edge, Ubuntu:18.04:LTS: linux-aws-5.0, Ubuntu:18.04:LTS: linux-aws-5.3, Ubuntu:18.04:LTS: linux-azure, Ubuntu:18.04:LTS: linux-azure-5.3, Ubuntu:18.04:LTS: linux-azure-edge, Ubuntu:18.04:LTS: linux-gcp, Ubuntu:18.04:LTS: linux-gcp-5.3, Ubuntu:18.04:LTS: linux-gke-4.15, Ubuntu:18.04:LTS: linux-gke-5.4 and 118 more

In the Linux kernel, the following vulnerability has been resolved: bpf, riscv: Fix extable handling for arena load_acquire emit_atomic_ld_st() returns 1 to have build_body() skip the zext after a sub-word load_acquire. The caller does "ret = ret ?: add_exception_handler(...)", which skips add_exception_handler() on any non-zero ret, so the extable entry is missing and a faulting PROBE_ATOMIC load_acquire oopses. REG_DONT_CLEAR_MARKER leaves rd stale on fault, and the verifier still thinks the load overwrote it, so a program can leak it through a map. Check ret >= 0 before calling add_exception_handler(), and pass rd for LOAD_ACQ so the fault zeroes rd like a PROBE_MEM load. Return ret unchanged for the zext skip.