If rcu_read_lock_sched tracing is enabled, the tracing subsystem can
perform a jump which needs to be checked by CFI. For example, stm_ftrace
source is enabled as a module and hooks into enabled ftrace events. This
can cause an recursive loop where find_shadow_check_fn ->
rcu_read_lock_sched -> (call to stm_ftrace generates cfi slowpath) ->
find_shadow_check_fn -> rcu_read_lock_sched -> ...
To avoid the recursion, either the ftrace codes needs to be marked with
__no_cfi or CFI should not trace. Use the "_notrace" in CFI to avoid
tracing so that CFI can guard ftrace.
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Cc: stable@vger.kernel.org
Fixes: cf68fffb66d6 ("add support for Clang CFI")
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20210811155914.19550-1-quic_eberman@quicinc.com
Bug: 194223154
Change-Id: I7d112496c7f503f95ba69390f6454623cf6dfed2
(cherry picked from commit 14c4c8e41511aa8fba7fb239b20b6539b5bce201)
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Use synchronize_rcu_expedited() to avoid RCU stalls when updating
the shadow while loading modules.
Bug: 178005287
Change-Id: I2a1235070bf8eb24fe4eabdc523a96c29adb04a1
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
This change adds the CONFIG_CFI_CLANG option, CFI error handling,
and a faster look-up table for cross module CFI checks.
Bug: 145210207
Change-Id: I68d620ca548a911e2f49ba801bc0531406e679a3
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
This reverts commit fa91466f31 as CFI is
being removed from the tree to come back later as a "clean" set of
patches.
Bug: 145210207
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I37cca753c39eef4c6fcef20e38d4f01fe78b4dee
This reverts commit c1ed22a5d9 as CFI is
being removed from the tree to come back later as a "clean" set of
patches.
Bug: 145210207
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: Ic11a9e73da2168a7b726d45a5f067846599e7188
In commit d71a92631c ("ANDROID: add support for Clang's Control Flow
Integrity (CFI)") some new symbols were exported, but they should have
been set as _GPL symbols.
Fix this up by properly.
Bug: 145210207
Cc: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I6ecbb0f3b33f7c02c9b75bb7d80c35ce80e553f3
This change adds the CONFIG_CFI_CLANG option, CFI error handling,
and a faster look-up table for cross module CFI checks.
Bug: 145210207
Change-Id: I118303de50114ca6f85d89a7d69c5cbc47e2f5c0
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
