sched_getattr(2) doesn't care about trailing non-zero bytes in the (ksize > usize) case, so just use copy_struct_to_user() without checking ignored_trailing.
Signed-off-by: Aleksa Sarai cyphar@cyphar.com --- kernel/sched/syscalls.c | 42 ++---------------------------------------- 1 file changed, 2 insertions(+), 40 deletions(-)
diff --git a/kernel/sched/syscalls.c b/kernel/sched/syscalls.c index ae1b42775ef9..4ccc058bae16 100644 --- a/kernel/sched/syscalls.c +++ b/kernel/sched/syscalls.c @@ -1147,45 +1147,6 @@ SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) return copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; }
-/* - * Copy the kernel size attribute structure (which might be larger - * than what user-space knows about) to user-space. - * - * Note that all cases are valid: user-space buffer can be larger or - * smaller than the kernel-space buffer. The usual case is that both - * have the same size. - */ -static int -sched_attr_copy_to_user(struct sched_attr __user *uattr, - struct sched_attr *kattr, - unsigned int usize) -{ - unsigned int ksize = sizeof(*kattr); - - if (!access_ok(uattr, usize)) - return -EFAULT; - - /* - * sched_getattr() ABI forwards and backwards compatibility: - * - * If usize == ksize then we just copy everything to user-space and all is good. - * - * If usize < ksize then we only copy as much as user-space has space for, - * this keeps ABI compatibility as well. We skip the rest. - * - * If usize > ksize then user-space is using a newer version of the ABI, - * which part the kernel doesn't know about. Just ignore it - tooling can - * detect the kernel's knowledge of attributes from the attr->size value - * which is set to ksize in this case. - */ - kattr->size = min(usize, ksize); - - if (copy_to_user(uattr, kattr, kattr->size)) - return -EFAULT; - - return 0; -} - /** * sys_sched_getattr - similar to sched_getparam, but with sched_attr * @pid: the pid in question. @@ -1230,7 +1191,8 @@ SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, #endif }
- return sched_attr_copy_to_user(uattr, &kattr, usize); + kattr.size = min(usize, sizeof(kattr)); + return copy_struct_to_user(uattr, usize, &kattr, sizeof(kattr), NULL); }
#ifdef CONFIG_SMP