Messages in this thread | | | Date | Wed, 2 Jul 2008 16:12:44 +1000 (EST) | From | James Morris <> | Subject | Re: [patch] security: fix dummy xattr functions |
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On Tue, 1 Jul 2008, Miklos Szeredi wrote:
> Hi James, > > If this (untested) patch looks OK, could you please apply it to your > tree?
As I understand it, filesystem capabilities is only enabled when either LSM is disabled, or the LSM capabilities module is built.
In both cases, security/commoncap.o is built. With LSM disabled, the correct cap_inode_xxx functions will be linked. With LSM+capabilities, either the capability LSM will be loaded, or another LSM will need to deliberately stack it.
So, I think the existing code is correct.
> > Replace open coded xattr checks with cap_inode_xxx() function calls in > dummy_inode_setxattr() and dummy_inode_removexattr(). The old ones > were out of sync with the cap_inode_xxx() implementation, which could > even be a security problem. > > Noticed by John Johansen. > > CC: John Johansen <jjohansen@suse.de> > Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> > --- > security/dummy.c | 12 ++---------- > 1 file changed, 2 insertions(+), 10 deletions(-) > > Index: linux-2.6/security/dummy.c > =================================================================== > --- linux-2.6.orig/security/dummy.c 2008-07-01 21:44:03.000000000 +0200 > +++ linux-2.6/security/dummy.c 2008-07-01 21:51:08.000000000 +0200 > @@ -370,11 +370,7 @@ static void dummy_inode_delete (struct i > static int dummy_inode_setxattr (struct dentry *dentry, const char *name, > const void *value, size_t size, int flags) > { > - if (!strncmp(name, XATTR_SECURITY_PREFIX, > - sizeof(XATTR_SECURITY_PREFIX) - 1) && > - !capable(CAP_SYS_ADMIN)) > - return -EPERM; > - return 0; > + return cap_inode_setxattr(dentry, name, value, size, flags); > } > > static void dummy_inode_post_setxattr (struct dentry *dentry, const char *name, > @@ -395,11 +391,7 @@ static int dummy_inode_listxattr (struct > > static int dummy_inode_removexattr (struct dentry *dentry, const char *name) > { > - if (!strncmp(name, XATTR_SECURITY_PREFIX, > - sizeof(XATTR_SECURITY_PREFIX) - 1) && > - !capable(CAP_SYS_ADMIN)) > - return -EPERM; > - return 0; > + return cap_inode_removexattr(dentry, name); > } > > static int dummy_inode_need_killpriv(struct dentry *dentry) >
-- James Morris <jmorris@namei.org>
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