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Revert 95ebabde38 ("capabilities: Don't allow writing ambiguous v3 file capabilities") 

It turns out that there are in fact userspace implementations that
care and this recent change caused a regression.

https://github.com/containers/buildah/issues/3071

As the motivation for the original change was future development,
and the impact is existing real world code just revert this change
and allow the ambiguity in v3 file caps.

Cc: stable@vger.kernel.org
Fixes: 95ebabde38 ("capabilities: Don't allow writing ambiguous v3 file capabilities")
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman 2021-03-12 15:07:09 -06:00
parent a38fd87484
commit 3b0c2d3eaa
1 changed files with 1 additions and 11 deletions
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12
security/commoncap.c
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@ -543,8 +543,7 @@ int cap_convert_nscap(struct user_namespace *mnt_userns, struct dentry *dentry,
__u32 magic, nsmagic;
struct inode *inode = d_backing_inode(dentry);
struct user_namespace *task_ns = current_user_ns(),
*fs_ns = inode->i_sb->s_user_ns,
*ancestor;
*fs_ns = inode->i_sb->s_user_ns;
kuid_t rootid;
size_t newsize;
@ -567,15 +566,6 @@ int cap_convert_nscap(struct user_namespace *mnt_userns, struct dentry *dentry,
if (nsrootid == -1)
return -EINVAL;
/*
* Do not allow allow adding a v3 filesystem capability xattr
* if the rootid field is ambiguous.
*/
for (ancestor = task_ns->parent; ancestor; ancestor = ancestor->parent) {
if (from_kuid(ancestor, rootid) == 0)
return -EINVAL;
}
newsize = sizeof(struct vfs_ns_cap_data);
nscap = kmalloc(newsize, GFP_ATOMIC);
if (!nscap)