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-rw-r--r--kernel/fs/sysfs/file.c6
-rw-r--r--kernel/fs/sysfs/group.c67
-rw-r--r--kernel/fs/sysfs/mount.c4
3 files changed, 70 insertions, 7 deletions
diff --git a/kernel/fs/sysfs/file.c b/kernel/fs/sysfs/file.c
index 7c2867b44..f35523d4f 100644
--- a/kernel/fs/sysfs/file.c
+++ b/kernel/fs/sysfs/file.c
@@ -90,7 +90,7 @@ static ssize_t sysfs_kf_bin_read(struct kernfs_open_file *of, char *buf,
return 0;
if (size) {
- if (pos > size)
+ if (pos >= size)
return 0;
if (pos + count > size)
count = size - pos;
@@ -108,6 +108,7 @@ static ssize_t sysfs_kf_read(struct kernfs_open_file *of, char *buf,
{
const struct sysfs_ops *ops = sysfs_file_ops(of->kn);
struct kobject *kobj = of->kn->parent->priv;
+ size_t len;
/*
* If buf != of->prealloc_buf, we don't know how
@@ -115,7 +116,8 @@ static ssize_t sysfs_kf_read(struct kernfs_open_file *of, char *buf,
*/
if (pos || WARN_ON_ONCE(buf != of->prealloc_buf))
return 0;
- return ops->show(kobj, of->kn->priv, buf);
+ len = ops->show(kobj, of->kn->priv, buf);
+ return min(count, len);
}
/* kernfs write callback for regular sysfs files */
diff --git a/kernel/fs/sysfs/group.c b/kernel/fs/sysfs/group.c
index b400c0437..dc1358b5e 100644
--- a/kernel/fs/sysfs/group.c
+++ b/kernel/fs/sysfs/group.c
@@ -73,13 +73,26 @@ static int create_files(struct kernfs_node *parent, struct kobject *kobj,
}
if (grp->bin_attrs) {
- for (bin_attr = grp->bin_attrs; *bin_attr; bin_attr++) {
+ for (i = 0, bin_attr = grp->bin_attrs; *bin_attr; i++, bin_attr++) {
+ umode_t mode = (*bin_attr)->attr.mode;
+
if (update)
kernfs_remove_by_name(parent,
(*bin_attr)->attr.name);
+ if (grp->is_bin_visible) {
+ mode = grp->is_bin_visible(kobj, *bin_attr, i);
+ if (!mode)
+ continue;
+ }
+
+ WARN(mode & ~(SYSFS_PREALLOC | 0664),
+ "Attribute %s: Invalid permissions 0%o\n",
+ (*bin_attr)->attr.name, mode);
+
+ mode &= SYSFS_PREALLOC | 0664;
error = sysfs_add_file_mode_ns(parent,
&(*bin_attr)->attr, true,
- (*bin_attr)->attr.mode, NULL);
+ mode, NULL);
if (error)
break;
}
@@ -135,7 +148,7 @@ static int internal_create_group(struct kobject *kobj, int update,
* This function creates a group for the first time. It will explicitly
* warn and error if any of the attribute files being created already exist.
*
- * Returns 0 on success or error.
+ * Returns 0 on success or error code on failure.
*/
int sysfs_create_group(struct kobject *kobj,
const struct attribute_group *grp)
@@ -155,7 +168,7 @@ EXPORT_SYMBOL_GPL(sysfs_create_group);
* It will explicitly warn and error if any of the attribute files being
* created already exist.
*
- * Returns 0 on success or error code from sysfs_create_group on error.
+ * Returns 0 on success or error code from sysfs_create_group on failure.
*/
int sysfs_create_groups(struct kobject *kobj,
const struct attribute_group **groups)
@@ -193,7 +206,7 @@ EXPORT_SYMBOL_GPL(sysfs_create_groups);
* The primary use for this function is to call it after making a change
* that affects group visibility.
*
- * Returns 0 on success or error.
+ * Returns 0 on success or error code on failure.
*/
int sysfs_update_group(struct kobject *kobj,
const struct attribute_group *grp)
@@ -352,3 +365,47 @@ void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
}
}
EXPORT_SYMBOL_GPL(sysfs_remove_link_from_group);
+
+/**
+ * __compat_only_sysfs_link_entry_to_kobj - add a symlink to a kobject pointing
+ * to a group or an attribute
+ * @kobj: The kobject containing the group.
+ * @target_kobj: The target kobject.
+ * @target_name: The name of the target group or attribute.
+ */
+int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
+ struct kobject *target_kobj,
+ const char *target_name)
+{
+ struct kernfs_node *target;
+ struct kernfs_node *entry;
+ struct kernfs_node *link;
+
+ /*
+ * We don't own @target_kobj and it may be removed at any time.
+ * Synchronize using sysfs_symlink_target_lock. See sysfs_remove_dir()
+ * for details.
+ */
+ spin_lock(&sysfs_symlink_target_lock);
+ target = target_kobj->sd;
+ if (target)
+ kernfs_get(target);
+ spin_unlock(&sysfs_symlink_target_lock);
+ if (!target)
+ return -ENOENT;
+
+ entry = kernfs_find_and_get(target_kobj->sd, target_name);
+ if (!entry) {
+ kernfs_put(target);
+ return -ENOENT;
+ }
+
+ link = kernfs_create_link(kobj->sd, target_name, entry);
+ if (IS_ERR(link) && PTR_ERR(link) == -EEXIST)
+ sysfs_warn_dup(kobj->sd, target_name);
+
+ kernfs_put(entry);
+ kernfs_put(target);
+ return IS_ERR(link) ? PTR_ERR(link) : 0;
+}
+EXPORT_SYMBOL_GPL(__compat_only_sysfs_link_entry_to_kobj);
diff --git a/kernel/fs/sysfs/mount.c b/kernel/fs/sysfs/mount.c
index 1c6ac6fce..f3db82071 100644
--- a/kernel/fs/sysfs/mount.c
+++ b/kernel/fs/sysfs/mount.c
@@ -40,6 +40,10 @@ static struct dentry *sysfs_mount(struct file_system_type *fs_type,
SYSFS_MAGIC, &new_sb, ns);
if (IS_ERR(root) || !new_sb)
kobj_ns_drop(KOBJ_NS_TYPE_NET, ns);
+ else if (new_sb)
+ /* Userspace would break if executables appear on sysfs */
+ root->d_sb->s_iflags |= SB_I_NOEXEC;
+
return root;
}