* [PATCH][capabilities-next] commoncap: move assignment of fs_ns to avoid null pointer dereference
@ 2017-09-04 17:50 Colin King
2017-09-04 18:53 ` Serge E. Hallyn
0 siblings, 1 reply; 4+ messages in thread
From: Colin King @ 2017-09-04 17:50 UTC (permalink / raw)
To: linux-security-module
From: Colin Ian King <colin.king@canonical.com>
The pointer fs_ns is assigned from inode->i_ib->s_user_ns before
a null pointer check on inode, hence if inode is actually null we
will get a null pointer dereference on this assignment. Fix this
by only dereferencing inode after the null pointer check on
inode.
Detected by CoverityScan CID#1455328 ("Dereference before null check")
Fixes: 8db6c34f1dbc ("Introduce v3 namespaced file capabilities")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
security/commoncap.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/security/commoncap.c b/security/commoncap.c
index c25e0d27537f..fc46f5b85251 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -585,13 +585,14 @@ int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data
struct vfs_ns_cap_data data, *nscaps = &data;
struct vfs_cap_data *caps = (struct vfs_cap_data *) &data;
kuid_t rootkuid;
- struct user_namespace *fs_ns = inode->i_sb->s_user_ns;
+ struct user_namespace *fs_ns;
memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
if (!inode)
return -ENODATA;
+ fs_ns = inode->i_sb->s_user_ns;
size = __vfs_getxattr((struct dentry *)dentry, inode,
XATTR_NAME_CAPS, &data, XATTR_CAPS_SZ);
if (size == -ENODATA || size == -EOPNOTSUPP)
--
2.14.1
--
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^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH][capabilities-next] commoncap: move assignment of fs_ns to avoid null pointer dereference
2017-09-04 17:50 [PATCH][capabilities-next] commoncap: move assignment of fs_ns to avoid null pointer dereference Colin King
@ 2017-09-04 18:53 ` Serge E. Hallyn
2017-10-11 20:48 ` Serge E. Hallyn
0 siblings, 1 reply; 4+ messages in thread
From: Serge E. Hallyn @ 2017-09-04 18:53 UTC (permalink / raw)
To: linux-security-module
On Mon, Sep 04, 2017 at 06:50:05PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
>
> The pointer fs_ns is assigned from inode->i_ib->s_user_ns before
> a null pointer check on inode, hence if inode is actually null we
> will get a null pointer dereference on this assignment. Fix this
> by only dereferencing inode after the null pointer check on
> inode.
>
> Detected by CoverityScan CID#1455328 ("Dereference before null check")
>
> Fixes: 8db6c34f1dbc ("Introduce v3 namespaced file capabilities")
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
thanks!
Acked-by: Serge Hallyn <serge@hallyn.com>
> ---
> security/commoncap.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/security/commoncap.c b/security/commoncap.c
> index c25e0d27537f..fc46f5b85251 100644
> --- a/security/commoncap.c
> +++ b/security/commoncap.c
> @@ -585,13 +585,14 @@ int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data
> struct vfs_ns_cap_data data, *nscaps = &data;
> struct vfs_cap_data *caps = (struct vfs_cap_data *) &data;
> kuid_t rootkuid;
> - struct user_namespace *fs_ns = inode->i_sb->s_user_ns;
> + struct user_namespace *fs_ns;
>
> memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
>
> if (!inode)
> return -ENODATA;
>
> + fs_ns = inode->i_sb->s_user_ns;
> size = __vfs_getxattr((struct dentry *)dentry, inode,
> XATTR_NAME_CAPS, &data, XATTR_CAPS_SZ);
> if (size == -ENODATA || size == -EOPNOTSUPP)
> --
> 2.14.1
--
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^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH][capabilities-next] commoncap: move assignment of fs_ns to avoid null pointer dereference
2017-09-04 18:53 ` Serge E. Hallyn
@ 2017-10-11 20:48 ` Serge E. Hallyn
2017-10-11 23:30 ` James Morris
0 siblings, 1 reply; 4+ messages in thread
From: Serge E. Hallyn @ 2017-10-11 20:48 UTC (permalink / raw)
To: linux-security-module
Hi James,
it doesn't look like this has been picked up yet. Assuming I'm not looking
in the wrong place, can you pull it into the security tree?
thanks,
-serge
Quoting Serge E. Hallyn (serge at hallyn.com):
> On Mon, Sep 04, 2017 at 06:50:05PM +0100, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> >
> > The pointer fs_ns is assigned from inode->i_ib->s_user_ns before
> > a null pointer check on inode, hence if inode is actually null we
> > will get a null pointer dereference on this assignment. Fix this
> > by only dereferencing inode after the null pointer check on
> > inode.
> >
> > Detected by CoverityScan CID#1455328 ("Dereference before null check")
> >
> > Fixes: 8db6c34f1dbc ("Introduce v3 namespaced file capabilities")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
>
> thanks!
>
> Acked-by: Serge Hallyn <serge@hallyn.com>
>
> > ---
> > security/commoncap.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/security/commoncap.c b/security/commoncap.c
> > index c25e0d27537f..fc46f5b85251 100644
> > --- a/security/commoncap.c
> > +++ b/security/commoncap.c
> > @@ -585,13 +585,14 @@ int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data
> > struct vfs_ns_cap_data data, *nscaps = &data;
> > struct vfs_cap_data *caps = (struct vfs_cap_data *) &data;
> > kuid_t rootkuid;
> > - struct user_namespace *fs_ns = inode->i_sb->s_user_ns;
> > + struct user_namespace *fs_ns;
> >
> > memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
> >
> > if (!inode)
> > return -ENODATA;
> >
> > + fs_ns = inode->i_sb->s_user_ns;
> > size = __vfs_getxattr((struct dentry *)dentry, inode,
> > XATTR_NAME_CAPS, &data, XATTR_CAPS_SZ);
> > if (size == -ENODATA || size == -EOPNOTSUPP)
> > --
> > 2.14.1
--
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^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH][capabilities-next] commoncap: move assignment of fs_ns to avoid null pointer dereference
2017-10-11 20:48 ` Serge E. Hallyn
@ 2017-10-11 23:30 ` James Morris
0 siblings, 0 replies; 4+ messages in thread
From: James Morris @ 2017-10-11 23:30 UTC (permalink / raw)
To: linux-security-module
On Wed, 11 Oct 2017, Serge E. Hallyn wrote:
> Hi James,
>
> it doesn't look like this has been picked up yet. Assuming I'm not looking
> in the wrong place, can you pull it into the security tree?
Sure, Colin, can you please resend this?
>
> Quoting Serge E. Hallyn (serge at hallyn.com):
> > On Mon, Sep 04, 2017 at 06:50:05PM +0100, Colin King wrote:
> > > From: Colin Ian King <colin.king@canonical.com>
> > >
> > > The pointer fs_ns is assigned from inode->i_ib->s_user_ns before
> > > a null pointer check on inode, hence if inode is actually null we
> > > will get a null pointer dereference on this assignment. Fix this
> > > by only dereferencing inode after the null pointer check on
> > > inode.
> > >
> > > Detected by CoverityScan CID#1455328 ("Dereference before null check")
> > >
> > > Fixes: 8db6c34f1dbc ("Introduce v3 namespaced file capabilities")
> > > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> >
> > thanks!
> >
> > Acked-by: Serge Hallyn <serge@hallyn.com>
> >
> > > ---
> > > security/commoncap.c | 3 ++-
> > > 1 file changed, 2 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/security/commoncap.c b/security/commoncap.c
> > > index c25e0d27537f..fc46f5b85251 100644
> > > --- a/security/commoncap.c
> > > +++ b/security/commoncap.c
> > > @@ -585,13 +585,14 @@ int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data
> > > struct vfs_ns_cap_data data, *nscaps = &data;
> > > struct vfs_cap_data *caps = (struct vfs_cap_data *) &data;
> > > kuid_t rootkuid;
> > > - struct user_namespace *fs_ns = inode->i_sb->s_user_ns;
> > > + struct user_namespace *fs_ns;
> > >
> > > memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data));
> > >
> > > if (!inode)
> > > return -ENODATA;
> > >
> > > + fs_ns = inode->i_sb->s_user_ns;
> > > size = __vfs_getxattr((struct dentry *)dentry, inode,
> > > XATTR_NAME_CAPS, &data, XATTR_CAPS_SZ);
> > > if (size == -ENODATA || size == -EOPNOTSUPP)
> > > --
> > > 2.14.1
> --
> To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
> the body of a message to majordomo at vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
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2017-09-04 17:50 [PATCH][capabilities-next] commoncap: move assignment of fs_ns to avoid null pointer dereference Colin King
2017-09-04 18:53 ` Serge E. Hallyn
2017-10-11 20:48 ` Serge E. Hallyn
2017-10-11 23:30 ` James Morris
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