[PATCH net-next 15/19] atm: separate ATM_GETNAMES handling from the rest of atm_dev_ioctl()

From: Al Viro
Date: Wed May 20 2020 - 20:37:52 EST


From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>

atm_dev_ioctl() does copyin in two different ways - one for
ATM_GETNAMES, another for everything else. Start with separating
the former into a new helper (atm_getnames()). The next step
will be to lift the copyin into the callers.

Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
---
net/atm/ioctl.c | 6 +++-
net/atm/resources.c | 88 +++++++++++++++++++++++++++--------------------------
net/atm/resources.h | 1 +
3 files changed, 51 insertions(+), 44 deletions(-)

diff --git a/net/atm/ioctl.c b/net/atm/ioctl.c
index d955b683aa7c..0b4b07740fe4 100644
--- a/net/atm/ioctl.c
+++ b/net/atm/ioctl.c
@@ -162,7 +162,11 @@ static int do_vcc_ioctl(struct socket *sock, unsigned int cmd,
if (error != -ENOIOCTLCMD)
goto done;

- error = atm_dev_ioctl(cmd, argp, compat);
+ if (cmd == ATM_GETNAMES) {
+ error = atm_getnames(argp, compat);
+ } else {
+ error = atm_dev_ioctl(cmd, argp, compat);
+ }

done:
return error;
diff --git a/net/atm/resources.c b/net/atm/resources.c
index 889349c6d90d..a2ab75929eec 100644
--- a/net/atm/resources.c
+++ b/net/atm/resources.c
@@ -193,61 +193,63 @@ static int fetch_stats(struct atm_dev *dev, struct atm_dev_stats __user *arg,
return error ? -EFAULT : 0;
}

-int atm_dev_ioctl(unsigned int cmd, void __user *arg, int compat)
+int atm_getnames(void __user *arg, int compat)
{
void __user *buf;
- int error, len, number, size = 0;
+ int error, len, size = 0;
struct atm_dev *dev;
struct list_head *p;
int *tmp_buf, *tmp_p;
- int __user *sioc_len;
int __user *iobuf_len;

- switch (cmd) {
- case ATM_GETNAMES:
- if (IS_ENABLED(CONFIG_COMPAT) && compat) {
+ if (IS_ENABLED(CONFIG_COMPAT) && compat) {
#ifdef CONFIG_COMPAT
- struct compat_atm_iobuf __user *ciobuf = arg;
- compat_uptr_t cbuf;
- iobuf_len = &ciobuf->length;
- if (get_user(cbuf, &ciobuf->buffer))
- return -EFAULT;
- buf = compat_ptr(cbuf);
+ struct compat_atm_iobuf __user *ciobuf = arg;
+ compat_uptr_t cbuf;
+ iobuf_len = &ciobuf->length;
+ if (get_user(cbuf, &ciobuf->buffer))
+ return -EFAULT;
+ buf = compat_ptr(cbuf);
#endif
- } else {
- struct atm_iobuf __user *iobuf = arg;
- iobuf_len = &iobuf->length;
- if (get_user(buf, &iobuf->buffer))
- return -EFAULT;
- }
- if (get_user(len, iobuf_len))
+ } else {
+ struct atm_iobuf __user *iobuf = arg;
+ iobuf_len = &iobuf->length;
+ if (get_user(buf, &iobuf->buffer))
return -EFAULT;
- mutex_lock(&atm_dev_mutex);
- list_for_each(p, &atm_devs)
- size += sizeof(int);
- if (size > len) {
- mutex_unlock(&atm_dev_mutex);
- return -E2BIG;
- }
- tmp_buf = kmalloc(size, GFP_ATOMIC);
- if (!tmp_buf) {
- mutex_unlock(&atm_dev_mutex);
- return -ENOMEM;
- }
- tmp_p = tmp_buf;
- list_for_each(p, &atm_devs) {
- dev = list_entry(p, struct atm_dev, dev_list);
- *tmp_p++ = dev->number;
- }
+ }
+ if (get_user(len, iobuf_len))
+ return -EFAULT;
+ mutex_lock(&atm_dev_mutex);
+ list_for_each(p, &atm_devs)
+ size += sizeof(int);
+ if (size > len) {
mutex_unlock(&atm_dev_mutex);
- error = ((copy_to_user(buf, tmp_buf, size)) ||
- put_user(size, iobuf_len))
- ? -EFAULT : 0;
- kfree(tmp_buf);
- return error;
- default:
- break;
+ return -E2BIG;
}
+ tmp_buf = kmalloc(size, GFP_ATOMIC);
+ if (!tmp_buf) {
+ mutex_unlock(&atm_dev_mutex);
+ return -ENOMEM;
+ }
+ tmp_p = tmp_buf;
+ list_for_each(p, &atm_devs) {
+ dev = list_entry(p, struct atm_dev, dev_list);
+ *tmp_p++ = dev->number;
+ }
+ mutex_unlock(&atm_dev_mutex);
+ error = ((copy_to_user(buf, tmp_buf, size)) ||
+ put_user(size, iobuf_len))
+ ? -EFAULT : 0;
+ kfree(tmp_buf);
+ return error;
+}
+
+int atm_dev_ioctl(unsigned int cmd, void __user *arg, int compat)
+{
+ void __user *buf;
+ int error, len, number, size = 0;
+ struct atm_dev *dev;
+ int __user *sioc_len;

if (IS_ENABLED(CONFIG_COMPAT) && compat) {
#ifdef CONFIG_COMPAT
diff --git a/net/atm/resources.h b/net/atm/resources.h
index 048232e4d4c6..18f8e5948ce4 100644
--- a/net/atm/resources.h
+++ b/net/atm/resources.h
@@ -14,6 +14,7 @@
extern struct list_head atm_devs;
extern struct mutex atm_dev_mutex;

+int atm_getnames(void __user *arg, int compat);
int atm_dev_ioctl(unsigned int cmd, void __user *arg, int compat);


--
2.11.0