[PATCH v3 01/11] stackleak: don't modify ctl_table argument

Thomas Weißschuh
2024-04-23T08:03:08Z

In a future commit the proc_handlers will change to
"const struct ctl_table".
As a preparation for that adapt the logic to work with a temporary
variable, similar to how it is done in other parts of the kernel.

Fixes: 964c9dff0091 ("stackleak: Allow runtime disabling of kernel stack erasing")
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
kernel/stackleak.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/stackleak.c b/kernel/stackleak.c
index d099f3affcf1..558b9d6d28d3 100644
--- a/kernel/stackleak.c
+++ b/kernel/stackleak.c
@@ -27,10 +27,11 @@ static int stack_erasing_sysctl(struct ctl_table *table, int write,
int ret = 0;
int state = !static_branch_unlikely(&stack_erasing_bypass);
int prev_state = state;
+ struct ctl_table tmp = *table;

- table->data = &state;
- table->maxlen = sizeof(int);
- ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+ tmp.data = &state;
+ tmp.maxlen = sizeof(int);
+ ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
state = !!state;
if (ret || !write || state == prev_state)
return ret;

--
2.44.0