git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 3b0c2d3eaa83da259d7726192cf55a137769012f Mon Sep 17 00:00:00 2001
   2 From: "Eric W. Biederman" <ebiederm@xmission.com>
   3 Date: Fri, 12 Mar 2021 15:07:09 -0600
   4 Subject: Revert 95ebabde382c ("capabilities: Don't allow writing ambiguous v3 file capabilities")
   5
   6 From: Eric W. Biederman <ebiederm@xmission.com>
   7
   8 commit 3b0c2d3eaa83da259d7726192cf55a137769012f upstream.
   9
  10 It turns out that there are in fact userspace implementations that
  11 care and this recent change caused a regression.
  12
  13 https://github.com/containers/buildah/issues/3071
  14
  15 As the motivation for the original change was future development,
  16 and the impact is existing real world code just revert this change
  17 and allow the ambiguity in v3 file caps.
  18
  19 Cc: stable@vger.kernel.org
  20 Fixes: 95ebabde382c ("capabilities: Don't allow writing ambiguous v3 file capabilities")
  21 Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
  22 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  23 ---
  24  security/commoncap.c |   12 +-----------
  25  1 file changed, 1 insertion(+), 11 deletions(-)
  26
  27 --- a/security/commoncap.c
  28 +++ b/security/commoncap.c
  29 @@ -506,8 +506,7 @@ int cap_convert_nscap(struct dentry *den
  30         __u32 magic, nsmagic;
  31         struct inode *inode = d_backing_inode(dentry);
  32         struct user_namespace *task_ns = current_user_ns(),
  33 -               *fs_ns = inode->i_sb->s_user_ns,
  34 -               *ancestor;
  35 +               *fs_ns = inode->i_sb->s_user_ns;
  36         kuid_t rootid;
  37         size_t newsize;
  38
  39 @@ -530,15 +529,6 @@ int cap_convert_nscap(struct dentry *den
  40         if (nsrootid == -1)
  41                 return -EINVAL;
  42
  43 -       /*
  44 -        * Do not allow allow adding a v3 filesystem capability xattr
  45 -        * if the rootid field is ambiguous.
  46 -        */
  47 -       for (ancestor = task_ns->parent; ancestor; ancestor = ancestor->parent) {
  48 -               if (from_kuid(ancestor, rootid) == 0)
  49 -                       return -EINVAL;
  50 -       }
  51 -
  52         newsize = sizeof(struct vfs_ns_cap_data);
  53         nscap = kmalloc(newsize, GFP_ATOMIC);
  54         if (!nscap)