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-rw-r--r--arch/riscv/include/asm/usercfi.h1
-rw-r--r--arch/riscv/kernel/usercfi.c3
-rw-r--r--tools/testing/selftests/riscv/cfi/cfitests.c6
3 files changed, 10 insertions, 0 deletions
diff --git a/arch/riscv/include/asm/usercfi.h b/arch/riscv/include/asm/usercfi.h
index f56966edbf5c..61ee02cee297 100644
--- a/arch/riscv/include/asm/usercfi.h
+++ b/arch/riscv/include/asm/usercfi.h
@@ -50,6 +50,7 @@ void set_indir_lp_status(struct task_struct *task, bool enable);
void set_indir_lp_lock(struct task_struct *task, bool lock);
#define PR_SHADOW_STACK_SUPPORTED_STATUS_MASK (PR_SHADOW_STACK_ENABLE)
+#define PR_CFI_SUPPORTED_STATUS_MASK (PR_CFI_ENABLE | PR_CFI_DISABLE | PR_CFI_LOCK)
#else
diff --git a/arch/riscv/kernel/usercfi.c b/arch/riscv/kernel/usercfi.c
index cbfb4e495e9f..5a7113d69bad 100644
--- a/arch/riscv/kernel/usercfi.c
+++ b/arch/riscv/kernel/usercfi.c
@@ -467,6 +467,9 @@ int arch_prctl_set_branch_landing_pad_state(struct task_struct *t, unsigned long
if (!is_user_lpad_enabled())
return -EINVAL;
+ if (state & ~PR_CFI_SUPPORTED_STATUS_MASK)
+ return -EINVAL;
+
/* indirect branch tracking is locked and further can't be modified by user */
if (is_indir_lp_locked(t))
return -EINVAL;
diff --git a/tools/testing/selftests/riscv/cfi/cfitests.c b/tools/testing/selftests/riscv/cfi/cfitests.c
index 39d097b6881f..0e3943461e7d 100644
--- a/tools/testing/selftests/riscv/cfi/cfitests.c
+++ b/tools/testing/selftests/riscv/cfi/cfitests.c
@@ -141,6 +141,12 @@ int main(int argc, char *argv[])
ksft_print_msg("Starting risc-v tests\n");
+ /* Test unknown PR_CFI bits */
+ ret = my_syscall5(__NR_prctl, PR_SET_CFI, PR_CFI_BRANCH_LANDING_PADS,
+ PR_CFI_ENABLE | 0xffff0, 0, 0);
+ if (!ret)
+ ksft_exit_fail_msg("PR_SET_CFI accepted reserved branch landing pad bits\n");
+
/*
* Landing pad test. Not a lot of kernel changes to support landing
* pads for user mode except lighting up a bit in senvcfg via a prctl.