diff options
Diffstat (limited to 'fs/namespace.c')
| -rw-r--r-- | fs/namespace.c | 29 |
1 files changed, 20 insertions, 9 deletions
diff --git a/fs/namespace.c b/fs/namespace.c index bae0e95b3713..294e05a13d17 100644 --- a/fs/namespace.c +++ b/fs/namespace.c @@ -3072,10 +3072,10 @@ static void shrink_submounts(struct mount *mnt) } } -void *copy_mount_options(const void __user * data) +static void *copy_mount_options(const void __user * data) { char *copy; - unsigned size; + unsigned left, offset; if (!data) return NULL; @@ -3084,20 +3084,31 @@ void *copy_mount_options(const void __user * data) if (!copy) return ERR_PTR(-ENOMEM); - size = PAGE_SIZE - offset_in_page(data); + left = copy_from_user(copy, data, PAGE_SIZE); - if (copy_from_user(copy, data, size)) { + /* + * Not all architectures have an exact copy_from_user(). Resort to + * byte at a time. + */ + offset = PAGE_SIZE - left; + while (left) { + char c; + if (get_user(c, (const char __user *)data + offset)) + break; + copy[offset] = c; + left--; + offset++; + } + + if (left == PAGE_SIZE) { kfree(copy); return ERR_PTR(-EFAULT); } - if (size != PAGE_SIZE) { - if (copy_from_user(copy + size, data + size, PAGE_SIZE - size)) - memset(copy + size, 0, PAGE_SIZE - size); - } + return copy; } -char *copy_mount_string(const void __user *data) +static char *copy_mount_string(const void __user *data) { return data ? strndup_user(data, PATH_MAX) : NULL; } |