>From 588755d9498c87c4e963527ba0f49c11107de354 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.
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..3e3d88c 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);
+clear_caps:
+ if (rc) {
+ 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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This contains a typo:
Serge E. Hallyn wrote:
>>From 588755d9498c87c4e963527ba0f49c11107de354 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.
[...]
> @@ -187,12 +186,21 @@ out:
> dput(dentry);
> if ((void *)dcaps != (void *)&v1caps)
> kfree(dcaps);
Move this two lines down (rc defaults to 0 in goto above):
from here-->
> +clear_caps:
> + if (rc) {
to here-->
> + cap_clear (bprm->cap_inheritable);
> + cap_clear (bprm->cap_permitted);
> + cap_clear (bprm->cap_effective);
> + }
> return rc;
Cheers
Andrew
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Quoting Andrew Morgan ([email protected]):
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> This contains a typo:
>
> Serge E. Hallyn wrote:
> >>From 588755d9498c87c4e963527ba0f49c11107de354 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.
> [...]
> > @@ -187,12 +186,21 @@ out:
> > dput(dentry);
> > if ((void *)dcaps != (void *)&v1caps)
> > 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.
If we didn't kmalloc it, dcaps==v1caps and it won't be freed.
thanks,
-serge
> > + cap_clear (bprm->cap_inheritable);
> > + cap_clear (bprm->cap_permitted);
> > + cap_clear (bprm->cap_effective);
> > + }
> > return rc;
>
> Cheers
>
> Andrew
>
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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 ... }'.
Cheers
Andrew
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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