In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
iommu\/tegra241-cmdqv: Synchronize the error ISR against VINTF (de)init<\/p>\n
A user VINTF is torn down by tegra241_cmdqv_deinit_vintf(), which runs from
\nthe destroy callback and from the init-failure unwind in the alloc handler.
\nIt clears the cmdqv->vintfs[] slot and lets the iommufd core free it, but
\nnothing serializes that against the error interrupt: tegra241_cmdqv_isr()
\nreads cmdqv->vintfs[idx] and dereferences the vintf. A concurrent error can
\nmake the ISR read a slot mid-clear (a NULL deref) or use a vintf which is
\nabout to be freed (a use-after-free).<\/p>\n
deinit_vintf() also returns idx to the IDA before clearing the slot, so a
\nconcurrent create that reuses idx can publish its new vintf into the slot,
\nonly for this teardown to erase it again with the stale NULL store.<\/p>\n
On the other end, tegra241_cmdqv_init_vintf() publishes a new vintf with a
\nplain store to the cmdqv->vintfs[] slot, and the ISR dereferences fields of
\na published vintf such as vintf->base. A plain store gives no ordering on a
\nweakly-ordered CPU, and a stale VINTF_ERR_MAP bit on a reused idx can make
\nthe ISR pick a vintf the moment it is published, before its fields are set
\nor tegra241_vintf_hw_init() runs.<\/p>\n
The cmdqv->vintfs[0] slot stays NULL until tegra241_cmdqv_init_structures()
\nfirst creates VINTF0, so the slot 0 read needs the same NULL check.<\/p>\n
Publish every slot with an smp_store_release(), and read each slot in the
\nISR with an smp_load_acquire() under a NULL check, so the ISR always sees
\na fully built vintf or NULL. Also make deinit_vintf() clear the slot, and
\nsynchronize_irq() prior to returning idx to the IDA, so no vintf is freed
\nunder a running handler and no reused idx is clobbered.<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
iommu\/tegra241-cmdqv: Synchronize the error ISR against VINTF (de)init<\/p>\n
A user VINTF is torn down by tegra241_cmdqv_deinit_vintf(),<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-25838","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/25838","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=25838"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=25838"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=25838"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}