| Message ID | 20210312004919.669614-16-samitolvanen@google.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | BPF |
| Headers | show |
| Series | Add support for Clang CFI | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On Thu, Mar 11, 2021 at 04:49:17PM -0800, Sami Tolvanen wrote: > __apply_alternatives makes indirect calls to functions whose address > is taken in assembly code using the alternative_cb macro. With > non-canonical CFI, the compiler won't replace these function > references with the jump table addresses, which trips CFI. Disable CFI > checking in the function to work around the issue. > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org>
diff --git a/arch/arm64/kernel/alternative.c b/arch/arm64/kernel/alternative.c index 1184c44ea2c7..abc84636af07 100644 --- a/arch/arm64/kernel/alternative.c +++ b/arch/arm64/kernel/alternative.c @@ -133,8 +133,8 @@ static void clean_dcache_range_nopatch(u64 start, u64 end) } while (cur += d_size, cur < end); } -static void __apply_alternatives(void *alt_region, bool is_module, - unsigned long *feature_mask) +static void __nocfi __apply_alternatives(void *alt_region, bool is_module, + unsigned long *feature_mask) { struct alt_instr *alt; struct alt_region *region = alt_region;
__apply_alternatives makes indirect calls to functions whose address is taken in assembly code using the alternative_cb macro. With non-canonical CFI, the compiler won't replace these function references with the jump table addresses, which trips CFI. Disable CFI checking in the function to work around the issue. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> --- arch/arm64/kernel/alternative.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)