[PATCH 4/4] sysctl: Don't call sysctl_follow_link unless we are a link.
From: Eric W. Biederman <hidden>
Date: 2012-02-02 03:30:04
Also in:
linux-fsdevel, lkml
Subsystem:
filesystems (vfs and infrastructure), proc filesystem, proc sysctl, the rest · Maintainers:
Alexander Viro, Christian Brauner, Kees Cook, Joel Granados, Linus Torvalds
There are no functional changes. Just code motion to make it clear that we don't follow a link between sysctl roots unless the directory entry actually is a link. Suggested-by: Lucian Adrian Grijincu <redacted> Signed-off-by: Eric W. Biederman <redacted> --- fs/proc/proc_sysctl.c | 24 ++++++++++++------------ 1 files changed, 12 insertions(+), 12 deletions(-)
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c
index e5601dc..a7708b7 100644
--- a/fs/proc/proc_sysctl.c
+++ b/fs/proc/proc_sysctl.c@@ -451,10 +451,12 @@ static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, if (!p) goto out; - ret = sysctl_follow_link(&h, &p, current->nsproxy); - err = ERR_PTR(ret); - if (ret) - goto out; + if (S_ISLNK(p->mode)) { + ret = sysctl_follow_link(&h, &p, current->nsproxy); + err = ERR_PTR(ret); + if (ret) + goto out; + } err = ERR_PTR(-ENOMEM); inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p);
@@ -601,10 +603,12 @@ static int proc_sys_link_fill_cache(struct file *filp, void *dirent, int err, ret = 0; head = sysctl_head_grab(head); - /* It is not an error if we can not follow the link ignore it */ - err = sysctl_follow_link(&head, &table, current->nsproxy); - if (err) - goto out; + if (S_ISLNK(table->mode)) { + /* It is not an error if we can not follow the link ignore it */ + err = sysctl_follow_link(&head, &table, current->nsproxy); + if (err) + goto out; + } ret = proc_sys_fill_cache(filp, dirent, filldir, head, table); out:
@@ -950,10 +954,6 @@ static int sysctl_follow_link(struct ctl_table_header **phead, struct ctl_dir *dir; int ret; - /* Get out quickly if not a link */ - if (!S_ISLNK((*pentry)->mode)) - return 0; - ret = 0; spin_lock(&sysctl_lock); root = (*pentry)->data;
--
1.7.2.5