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saner calling conventions for copy_mount_options()

Browse source 
let it just return NULL, pointer to kernel copy or ERR_PTR().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2015-12-14 18:44:44 -05:00
parent cc4e719e83
commit b40ef8696f
3 changed files with 28 additions and 30 deletions
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21
fs/compat.c
View file

@ -792,7 +792,7 @@ COMPAT_SYSCALL_DEFINE5(mount, const char __user *, dev_name,
const void __user *, data)
{
char *kernel_type;
unsigned long data_page;
void *options;
char *kernel_dev;
int retval;
@ -806,26 +806,25 @@ COMPAT_SYSCALL_DEFINE5(mount, const char __user *, dev_name,
if (IS_ERR(kernel_dev))
goto out1;
retval = copy_mount_options(data, &data_page);
if (retval < 0)
options = copy_mount_options(data);
retval = PTR_ERR(options);
if (IS_ERR(options))
goto out2;
retval = -EINVAL;
if (kernel_type && data_page) {
if (kernel_type && options) {
if (!strcmp(kernel_type, NCPFS_NAME)) {
do_ncp_super_data_conv((void *)data_page);
do_ncp_super_data_conv(options);
} else if (!strcmp(kernel_type, NFS4_NAME)) {
if (do_nfs4_super_data_conv((void *) data_page))
retval = -EINVAL;
if (do_nfs4_super_data_conv(options))
goto out3;
}
}
retval = do_mount(kernel_dev, dir_name, kernel_type,
flags, (void*)data_page);
retval = do_mount(kernel_dev, dir_name, kernel_type, flags, options);
out3:
free_page(data_page);
kfree(options);
out2:
kfree(kernel_dev);
out1:

2
fs/internal.h
View file

@ -55,7 +55,7 @@ extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
/*
* namespace.c
*/
extern int copy_mount_options(const void __user *, unsigned long *);
extern void *copy_mount_options(const void __user *);
extern char *copy_mount_string(const void __user *);
extern struct vfsmount *lookup_mnt(struct path *);

35
fs/namespace.c
View file

@ -2601,18 +2601,18 @@ static long exact_copy_from_user(void *to, const void __user * from,
return n;
}
int copy_mount_options(const void __user * data, unsigned long *where)
void *copy_mount_options(const void __user * data)
{
int i;
unsigned long page;
unsigned long size;
char *copy;
*where = 0;
if (!data)
return 0;
return NULL;
if (!(page = __get_free_page(GFP_KERNEL)))
return -ENOMEM;
copy = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (!copy)
return ERR_PTR(-ENOMEM);
/* We only care that *some* data at the address the user
* gave us is valid. Just in case, we'll zero
@ -2623,15 +2623,14 @@ int copy_mount_options(const void __user * data, unsigned long *where)
if (size > PAGE_SIZE)
size = PAGE_SIZE;
i = size - exact_copy_from_user((void *)page, data, size);
i = size - exact_copy_from_user(copy, data, size);
if (!i) {
free_page(page);
return -EFAULT;
kfree(copy);
return ERR_PTR(-EFAULT);
}
if (i != PAGE_SIZE)
memset((char *)page + i, 0, PAGE_SIZE - i);
*where = page;
return 0;
memset(copy + i, 0, PAGE_SIZE - i);
return copy;
}
char *copy_mount_string(const void __user *data)
@ -2896,7 +2895,7 @@ SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
int ret;
char *kernel_type;
char *kernel_dev;
unsigned long data_page;
void *options;
kernel_type = copy_mount_string(type);
ret = PTR_ERR(kernel_type);
@ -2908,14 +2907,14 @@ SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
if (IS_ERR(kernel_dev))
goto out_dev;
ret = copy_mount_options(data, &data_page);
if (ret < 0)
options = copy_mount_options(data);
ret = PTR_ERR(options);
if (IS_ERR(options))
goto out_data;
ret = do_mount(kernel_dev, dir_name, kernel_type, flags,
(void *) data_page);
ret = do_mount(kernel_dev, dir_name, kernel_type, flags, options);
free_page(data_page);
kfree(options);
out_data:
kfree(kernel_dev);
out_dev: