Verity targets can be configured to ignore corrupted data blocks.
LoadPin must only trust verity targets that are configured to
perform some kind of enforcement when data corruption is detected,
like returning an error, restarting the system or triggering a
panic.
Fixes: b6c1c5745c ("dm: Add verity helpers for LoadPin")
Reported-by: Sarthak Kukreti <sarthakkukreti@chromium.org>
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Sarthak Kukreti <sarthakkukreti@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220907133055.1.Ic8a1dafe960dc0f8302e189642bc88ebb785d274@changeid
Commit 2aec377a29 ("dm table: remove dm_table_get_num_targets()
wrapper") in linux-dm/for-next removed the function
dm_table_get_num_targets() which is used by verity-loadpin. Access
table->num_targets directly instead of using the defunct wrapper.
Fixes: b6c1c5745c ("dm: Add verity helpers for LoadPin")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220728085412.1.I242d21b378410eb6f9897a3160efb56e5608c59d@changeid
LoadPin limits loading of kernel modules, firmware and certain
other files to a 'pinned' file system (typically a read-only
rootfs). To provide more flexibility LoadPin is being extended
to also allow loading these files from trusted dm-verity
devices. For that purpose LoadPin can be provided with a list
of verity root digests that it should consider as trusted.
Add a bunch of helpers to allow LoadPin to check whether a DM
device is a trusted verity device. The new functions broadly
fall in two categories: those that need access to verity
internals (like the root digest), and the 'glue' between
LoadPin and verity. The new file dm-verity-loadpin.c contains
the glue functions.
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Acked-by: Mike Snitzer <snitzer@kernel.org>
Link: https://lore.kernel.org/lkml/20220627083512.v7.1.I3e928575a23481121e73286874c4c2bdb403355d@changeid
Signed-off-by: Kees Cook <keescook@chromium.org>
