Quoting Andrew Morgan ([EMAIL PROTECTED]):
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> Serge E. Hallyn wrote:
> >>>>                  kfree(dcaps);
> > Move this two lines down (rc defaults to 0 in goto above):
> > from here-->
> >>>> +clear_caps:
> >>>> +        if (rc) {
> > to here-->
> > 
> >> Hmm?  But if we succeeded we still want to free dcaps if we
> >> kmalloc()'d it.
> 
> I wasn't clear enough... Let me try again with different words.
> 
> If you look at your patch, you will see that the only use of the label
> 'clear_caps:' is as a jump target from a location in which rc=0. As
> such, you will *not* clear the bprm->cap_* sets... This is the reverse
> of what you intended to do.
> 
> You need to put the jump target 'inside' the 'if (rc) { <-here ... }'.

Oops!  Good catch, thanks.  New patch follows:

>From 9e8d4dd0486c85e269a062a4637a8b6296fcb80b Mon Sep 17 00:00:00 2001
From: Serge E. Hallyn <[EMAIL PROTECTED]>
Date: Wed, 27 Jun 2007 19:55:27 -0400
Subject: [PATCH 1/1] file capabilities: get_file_caps cleanups

Two cleanups relating to set_file caps.

Rename set_file_caps to get_file_caps, since we are getting
the file capabilities, and setting the bprm caps to them.

Move the clearing of bprm caps into get_file_caps, and do it
only when we don't copy them from the capability xattr.

Changelog:
        Fix location of 'clear_caps' label.

Signed-off-by: Serge E. Hallyn <[EMAIL PROTECTED]>
---
 security/commoncap.c |   26 ++++++++++++++------------
 1 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/security/commoncap.c b/security/commoncap.c
index 24de4fa..cc50a61 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -135,21 +135,20 @@ static inline int cap_from_disk(struct vfs_cap_data_disk 
*dcap,
 }
 
 /* Locate any VFS capabilities: */
-static int set_file_caps(struct linux_binprm *bprm)
+static int get_file_caps(struct linux_binprm *bprm)
 {
        struct dentry *dentry;
-       int rc;
+       int rc = 0;
        struct vfs_cap_data_disk_v1 v1caps;
        struct vfs_cap_data_disk *dcaps;
        struct inode *inode;
 
        dcaps = (struct vfs_cap_data_disk *)&v1caps;
        if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID)
-               return 0;
+               goto clear_caps;
 
        dentry = dget(bprm->file->f_dentry);
        inode = dentry->d_inode;
-       rc = 0;
        if (!inode->i_op || !inode->i_op->getxattr)
                goto out;
 
@@ -187,12 +186,21 @@ out:
        dput(dentry);
        if ((void *)dcaps != (void *)&v1caps)
                kfree(dcaps);
+       if (rc) {
+clear_caps:
+               cap_clear (bprm->cap_inheritable);
+               cap_clear (bprm->cap_permitted);
+               cap_clear (bprm->cap_effective);
+       }
        return rc;
 }
 
 #else
-static inline int set_file_caps(struct linux_binprm *bprm)
+static inline int get_file_caps(struct linux_binprm *bprm)
 {
+       cap_clear (bprm->cap_inheritable);
+       cap_clear (bprm->cap_permitted);
+       cap_clear (bprm->cap_effective);
        return 0;
 }
 #endif
@@ -201,13 +209,7 @@ int cap_bprm_set_security (struct linux_binprm *bprm)
 {
        int ret;
 
-       /* Copied from fs/exec.c:prepare_binprm. */
-
-       cap_clear (bprm->cap_inheritable);
-       cap_clear (bprm->cap_permitted);
-       cap_clear (bprm->cap_effective);
-
-       ret = set_file_caps(bprm);
+       ret = get_file_caps(bprm);
 
        /*  To support inheritance of root-permissions and suid-root
         *  executables under compatibility mode, we raise all three
-- 
1.5.1.1.GIT

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