diff options
| author |   Ivan Delalande <colona@arista.com> | 2018-12-13 15:20:52 -0800 |
|---|---|---|
| committer |   Al Viro <viro@zeniv.linux.org.uk> | 2018-12-13 20:59:44 -0500 |
| commit | ea5751ccd665a2fd1b24f9af81f6167f0718c5f6 (patch) | |
| tree | 1cc50a3dbdf449f104a3cb4295ed84193607180c /fs/proc/proc_sysctl.c | |
| parent | aio: fix spectre gadget in lookup_ioctx (diff) | |
| download | wireguard-linux-ea5751ccd665a2fd1b24f9af81f6167f0718c5f6.tar.xz wireguard-linux-ea5751ccd665a2fd1b24f9af81f6167f0718c5f6.zip | |
proc/sysctl: don't return ENOMEM on lookup when a table is unregistering
proc_sys_lookup can fail with ENOMEM instead of ENOENT when the
corresponding sysctl table is being unregistered. In our case we see
this upon opening /proc/sys/net/*/conf files while network interfaces
are being deleted, which confuses our configuration daemon.
The problem was successfully reproduced and this fix tested on v4.9.122
and v4.20-rc6.
v2: return ERR_PTRs in all cases when proc_sys_make_inode fails instead
of mixing them with NULL. Thanks Al Viro for the feedback.
Fixes: ace0c791e6c3 ("proc/sysctl: Don't grab i_lock under sysctl_lock.")
Cc: stable@vger.kernel.org
Signed-off-by: Ivan Delalande <colona@arista.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/proc/proc_sysctl.c')
| -rw-r--r-- | fs/proc/proc_sysctl.c | 13 |
1 files changed, 6 insertions, 7 deletions
diff --git a/fs/proc/proc_sysctl.c b/fs/proc/proc_sysctl.c index 89921a0d2ebb..4d598a399bbf 100644 --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -464,7 +464,7 @@ static struct inode *proc_sys_make_inode(struct super_block *sb, inode = new_inode(sb); if (!inode) - goto out; + return ERR_PTR(-ENOMEM); inode->i_ino = get_next_ino(); @@ -474,8 +474,7 @@ static struct inode *proc_sys_make_inode(struct super_block *sb, if (unlikely(head->unregistering)) { spin_unlock(&sysctl_lock); iput(inode); - inode = NULL; - goto out; + return ERR_PTR(-ENOENT); } ei->sysctl = head; ei->sysctl_entry = table; @@ -500,7 +499,6 @@ static struct inode *proc_sys_make_inode(struct super_block *sb, if (root->set_ownership) root->set_ownership(head, table, &inode->i_uid, &inode->i_gid); -out: return inode; } @@ -549,10 +547,11 @@ static struct dentry *proc_sys_lookup(struct inode *dir, struct dentry *dentry, goto out; } - err = ERR_PTR(-ENOMEM); inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); - if (!inode) + if (IS_ERR(inode)) { + err = ERR_CAST(inode); goto out; + } d_set_d_op(dentry, &proc_sys_dentry_operations); err = d_splice_alias(inode, dentry); @@ -685,7 +684,7 @@ static bool proc_sys_fill_cache(struct file *file, if (d_in_lookup(child)) { struct dentry *res; inode = proc_sys_make_inode(dir->d_sb, head, table); - if (!inode) { + if (IS_ERR(inode)) { d_lookup_done(child); dput(child); return false; |