lkml.org 
[lkml]   [2007]   [Jun]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: [PATCH 1/1] file capabilities: get_file_caps cleanups
Quoting Andrew Morgan (morgan@kernel.org):
> -----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 <serue@us.ibm.com>
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 <serue@us.ibm.com>
---
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
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2007-06-28 18:53    [W:0.043 / U:0.052 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site