In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
bpf: Reset register bounds before narrowing retval range in check_mem_access()<\/p>\n
When the BPF verifier processes a context load of an LSM hook return
\nvalue, it calls __mark_reg_s32_range() to narrow the register to the
\nhook’s valid range. However, __mark_reg_s32_range() intersects the new
\nrange with the register’s existing bounds using max_t()\/min_t() rather
\nthan replacing them.<\/p>\n
If the destination register carries stale bounds from a prior instruction
\n(e.g. BPF_MOV64_IMM), the intersection can produce a range narrower than
\nreality. The verifier then believes it knows the register’s exact value,
\nwhile at runtime the actual hook return value is loaded, creating a
\nverifier\/runtime mismatch that can be used to bypass BPF memory safety
\nchecks.<\/p>\n
The else branch already calls mark_reg_unknown() to reset register state
\nbefore any narrowing. Apply the same reset in the is_retval path so
\nstale bounds are cleared before __mark_reg_s32_range() intersects.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
bpf: Reset register bounds before narrowing retval range in check_mem_access()<\/p>\n
When the BPF verifier processes a context load of a<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-6779","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/6779","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6779"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6779"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6779"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}