oss-sec mailing list archives
Re: [RFC PATCH RESEND] vfs: Move security_inode_killpriv() after permission checks
From: James Morris <jmorris () namei org>
Date: Wed, 21 Jan 2015 10:17:29 +1100 (AEDT)
On Sat, 17 Jan 2015, Ben Hutchings wrote:
chown() and write() should clear all privilege attributes on a file - setuid, setgid, setcap and any other extended privilege attributes. However, any attributes beyond setuid and setgid are managed by the LSM and not directly by the filesystem, so they cannot be set along with the other attributes. Currently we call security_inode_killpriv() in notify_change(), but in case of a chown() this is too early - we have not called inode_change_ok() or made any filesystem-specific permission/sanity checks. Add a new function setattr_killpriv() which calls security_inode_killpriv() if necessary, and change the setattr() implementation to call this in each filesystem that supports xattrs. This assumes that extended privilege attributes are always stored in xattrs.
It'd be useful to get some input from LSM module maintainers on this. e.g. doesn't SELinux already handle this via policy directives? -- James Morris <jmorris () namei org>
Current thread:
- [RFC PATCH RESEND] vfs: Move security_inode_killpriv() after permission checks Ben Hutchings (Jan 17)
- Re: [RFC PATCH RESEND] vfs: Move security_inode_killpriv() after permission checks James Morris (Jan 20)
- Re: [RFC PATCH RESEND] vfs: Move security_inode_killpriv() after permission checks Casey Schaufler (Jan 20)
- Re: [RFC PATCH RESEND] vfs: Move security_inode_killpriv() after permission checks Stephen Smalley (Jan 21)
- Re: [RFC PATCH RESEND] vfs: Move security_inode_killpriv() after permission checks Casey Schaufler (Jan 21)
- Re: [RFC PATCH RESEND] vfs: Move security_inode_killpriv() after permission checks Solar Designer (Jan 21)
- Re: [RFC PATCH RESEND] vfs: Move security_inode_killpriv() after permission checks Ben Hutchings (Jan 21)
- Re: [RFC PATCH RESEND] vfs: Move security_inode_killpriv() after permission checks Josh Boyer (Feb 16)
- Re: [RFC PATCH RESEND] vfs: Move security_inode_killpriv() after permission checks James Morris (Jan 20)