btrfs: Make btrfs handle security mount options internally to avoid losing security...

[cascardo/linux.git] / fs / btrfs / sysfs.c

diff --git a/fs/btrfs/sysfs.c b/fs/btrfs/sysfs.c
index 12e5355..b2e7bb4 100644 (file)
--- a/fs/btrfs/sysfs.c
+++ b/fs/btrfs/sysfs.c
@@ -242,7 +242,7 @@ static ssize_t global_rsv_size_show(struct kobject *kobj,
        struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
        return btrfs_show_u64(&block_rsv->size, &block_rsv->lock, buf);
 }
-BTRFS_ATTR(global_rsv_size, 0444, global_rsv_size_show);
+BTRFS_ATTR(global_rsv_size, global_rsv_size_show);
 
 static ssize_t global_rsv_reserved_show(struct kobject *kobj,
                                        struct kobj_attribute *a, char *buf)
@@ -251,7 +251,7 @@ static ssize_t global_rsv_reserved_show(struct kobject *kobj,
        struct btrfs_block_rsv *block_rsv = &fs_info->global_block_rsv;
        return btrfs_show_u64(&block_rsv->reserved, &block_rsv->lock, buf);
 }
-BTRFS_ATTR(global_rsv_reserved, 0444, global_rsv_reserved_show);
+BTRFS_ATTR(global_rsv_reserved, global_rsv_reserved_show);
 
 #define to_space_info(_kobj) container_of(_kobj, struct btrfs_space_info, kobj)
 #define to_raid_kobj(_kobj) container_of(_kobj, struct raid_kobject, kobj)
@@ -306,7 +306,7 @@ static ssize_t btrfs_space_info_show_##field(struct kobject *kobj,  \
        struct btrfs_space_info *sinfo = to_space_info(kobj);           \
        return btrfs_show_u64(&sinfo->field, &sinfo->lock, buf);        \
 }                                                                      \
-BTRFS_ATTR(field, 0444, btrfs_space_info_show_##field)
+BTRFS_ATTR(field, btrfs_space_info_show_##field)
 
 static ssize_t btrfs_space_info_show_total_bytes_pinned(struct kobject *kobj,
                                                       struct kobj_attribute *a,
@@ -325,7 +325,7 @@ SPACE_INFO_ATTR(bytes_reserved);
 SPACE_INFO_ATTR(bytes_may_use);
 SPACE_INFO_ATTR(disk_used);
 SPACE_INFO_ATTR(disk_total);
-BTRFS_ATTR(total_bytes_pinned, 0444, btrfs_space_info_show_total_bytes_pinned);
+BTRFS_ATTR(total_bytes_pinned, btrfs_space_info_show_total_bytes_pinned);
 
 static struct attribute *space_info_attrs[] = {
        BTRFS_ATTR_PTR(flags),
@@ -363,7 +363,8 @@ static ssize_t btrfs_label_show(struct kobject *kobj,
                                struct kobj_attribute *a, char *buf)
 {
        struct btrfs_fs_info *fs_info = to_fs_info(kobj);
-       return snprintf(buf, PAGE_SIZE, "%s\n", fs_info->super_copy->label);
+       char *label = fs_info->super_copy->label;
+       return snprintf(buf, PAGE_SIZE, label[0] ? "%s\n" : "%s", label);
 }
 
 static ssize_t btrfs_label_store(struct kobject *kobj,
@@ -374,8 +375,18 @@ static ssize_t btrfs_label_store(struct kobject *kobj,
        struct btrfs_trans_handle *trans;
        struct btrfs_root *root = fs_info->fs_root;
        int ret;
+       size_t p_len;
 
-       if (len >= BTRFS_LABEL_SIZE)
+       if (fs_info->sb->s_flags & MS_RDONLY)
+               return -EROFS;
+
+       /*
+        * p_len is the len until the first occurrence of either
+        * '\n' or '\0'
+        */
+       p_len = strcspn(buf, "\n");
+
+       if (p_len >= BTRFS_LABEL_SIZE)
                return -EINVAL;
 
        trans = btrfs_start_transaction(root, 0);
@@ -383,7 +394,8 @@ static ssize_t btrfs_label_store(struct kobject *kobj,
                return PTR_ERR(trans);
 
        spin_lock(&root->fs_info->super_lock);
-       strcpy(fs_info->super_copy->label, buf);
+       memset(fs_info->super_copy->label, 0, BTRFS_LABEL_SIZE);
+       memcpy(fs_info->super_copy->label, buf, p_len);
        spin_unlock(&root->fs_info->super_lock);
        ret = btrfs_commit_transaction(trans, root);
 
@@ -392,14 +404,7 @@ static ssize_t btrfs_label_store(struct kobject *kobj,
 
        return ret;
 }
-BTRFS_ATTR_RW(label, 0644, btrfs_label_show, btrfs_label_store);
-
-static ssize_t btrfs_no_store(struct kobject *kobj,
-                                struct kobj_attribute *a,
-                                const char *buf, size_t len)
-{
-       return -EPERM;
-}
+BTRFS_ATTR_RW(label, btrfs_label_show, btrfs_label_store);
 
 static ssize_t btrfs_nodesize_show(struct kobject *kobj,
                                struct kobj_attribute *a, char *buf)
@@ -409,7 +414,7 @@ static ssize_t btrfs_nodesize_show(struct kobject *kobj,
        return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->nodesize);
 }
 
-BTRFS_ATTR_RW(nodesize, 0444, btrfs_nodesize_show, btrfs_no_store);
+BTRFS_ATTR(nodesize, btrfs_nodesize_show);
 
 static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
                                struct kobj_attribute *a, char *buf)
@@ -419,7 +424,7 @@ static ssize_t btrfs_sectorsize_show(struct kobject *kobj,
        return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->sectorsize);
 }
 
-BTRFS_ATTR_RW(sectorsize, 0444, btrfs_sectorsize_show, btrfs_no_store);
+BTRFS_ATTR(sectorsize, btrfs_sectorsize_show);
 
 static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
                                struct kobj_attribute *a, char *buf)
@@ -429,7 +434,7 @@ static ssize_t btrfs_clone_alignment_show(struct kobject *kobj,
        return snprintf(buf, PAGE_SIZE, "%u\n", fs_info->super_copy->sectorsize);
 }
 
-BTRFS_ATTR_RW(clone_alignment, 0444, btrfs_clone_alignment_show, btrfs_no_store);
+BTRFS_ATTR(clone_alignment, btrfs_clone_alignment_show);
 
 static struct attribute *btrfs_attrs[] = {
        BTRFS_ATTR_PTR(label),