From: Roberto Sassu <[email protected]>
In preparation for moving IMA and EVM to the LSM infrastructure, introduce
the inode_post_removexattr hook.
Signed-off-by: Roberto Sassu <[email protected]>
---
fs/xattr.c | 1 +
include/linux/lsm_hook_defs.h | 2 ++
include/linux/security.h | 5 +++++
security/security.c | 14 ++++++++++++++
4 files changed, 22 insertions(+)
diff --git a/fs/xattr.c b/fs/xattr.c
index 14a7eb3c8fa..10c959d9fc6 100644
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -534,6 +534,7 @@ __vfs_removexattr_locked(struct mnt_idmap *idmap,
if (!error) {
fsnotify_xattr(dentry);
+ security_inode_post_removexattr(dentry, name);
evm_inode_post_removexattr(dentry, name);
}
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index eedefbcdde3..2ae5224d967 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -147,6 +147,8 @@ LSM_HOOK(int, 0, inode_getxattr, struct dentry *dentry, const char *name)
LSM_HOOK(int, 0, inode_listxattr, struct dentry *dentry)
LSM_HOOK(int, 0, inode_removexattr, struct mnt_idmap *idmap,
struct dentry *dentry, const char *name)
+LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry,
+ const char *name)
LSM_HOOK(int, 0, inode_set_acl, struct mnt_idmap *idmap,
struct dentry *dentry, const char *acl_name, struct posix_acl *kacl)
LSM_HOOK(int, 0, inode_get_acl, struct mnt_idmap *idmap,
diff --git a/include/linux/security.h b/include/linux/security.h
index 64224216f6c..b511f608958 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -373,6 +373,7 @@ int security_inode_getxattr(struct dentry *dentry, const char *name);
int security_inode_listxattr(struct dentry *dentry);
int security_inode_removexattr(struct mnt_idmap *idmap,
struct dentry *dentry, const char *name);
+void security_inode_post_removexattr(struct dentry *dentry, const char *name);
int security_inode_need_killpriv(struct dentry *dentry);
int security_inode_killpriv(struct mnt_idmap *idmap, struct dentry *dentry);
int security_inode_getsecurity(struct mnt_idmap *idmap,
@@ -918,6 +919,10 @@ static inline int security_inode_removexattr(struct mnt_idmap *idmap,
return cap_inode_removexattr(idmap, dentry, name);
}
+static inline void security_inode_post_removexattr(struct dentry *dentry,
+ const char *name)
+{ }
+
static inline int security_inode_need_killpriv(struct dentry *dentry)
{
return cap_inode_need_killpriv(dentry);
diff --git a/security/security.c b/security/security.c
index 2dbf225f5d8..6bf4a92db94 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2404,6 +2404,20 @@ int security_inode_removexattr(struct mnt_idmap *idmap,
return evm_inode_removexattr(idmap, dentry, name);
}
+/**
+ * security_inode_post_removexattr() - Update the inode after a removexattr op
+ * @dentry: file
+ * @name: xattr name
+ *
+ * Update the inode after a successful removexattr operation.
+ */
+void security_inode_post_removexattr(struct dentry *dentry, const char *name)
+{
+ if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
+ return;
+ call_void_hook(inode_post_removexattr, dentry, name);
+}
+
/**
* security_inode_need_killpriv() - Check if security_inode_killpriv() required
* @dentry: associated dentry
--
2.25.1
On 3/3/23 13:18, Roberto Sassu wrote:
> From: Roberto Sassu <[email protected]>
>
> In preparation for moving IMA and EVM to the LSM infrastructure, introduce
> the inode_post_removexattr hook.
>
> Signed-off-by: Roberto Sassu <[email protected]>
Reviewed-by: Stefan Berger <[email protected]>
Hi Roberto,
On Fri, 2023-03-03 at 19:18 +0100, Roberto Sassu wrote:
> From: Roberto Sassu <[email protected]>
>
> In preparation for moving IMA and EVM to the LSM infrastructure, introduce
> the inode_post_removexattr hook.
>
> Signed-off-by: Roberto Sassu <[email protected]>
> ---
> fs/xattr.c | 1 +
> include/linux/lsm_hook_defs.h | 2 ++
> include/linux/security.h | 5 +++++
> security/security.c | 14 ++++++++++++++
> 4 files changed, 22 insertions(+)
>
> diff --git a/fs/xattr.c b/fs/xattr.c
> index 14a7eb3c8fa..10c959d9fc6 100644
> --- a/fs/xattr.c
> +++ b/fs/xattr.c
> @@ -534,6 +534,7 @@ __vfs_removexattr_locked(struct mnt_idmap *idmap,
>
> if (!error) {
> fsnotify_xattr(dentry);
> + security_inode_post_removexattr(dentry, name);
> evm_inode_post_removexattr(dentry, name);
> }
Nothing wrong with this, but other places in this function test "if
(error) goto ...". Perhaps it is time to clean this up.
>
> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
> index eedefbcdde3..2ae5224d967 100644
> --- a/include/linux/lsm_hook_defs.h
> +++ b/include/linux/lsm_hook_defs.h
> @@ -147,6 +147,8 @@ LSM_HOOK(int, 0, inode_getxattr, struct dentry *dentry, const char *name)
> LSM_HOOK(int, 0, inode_listxattr, struct dentry *dentry)
> LSM_HOOK(int, 0, inode_removexattr, struct mnt_idmap *idmap,
> struct dentry *dentry, const char *name)
> +LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry,
> + const char *name)
@Christian should the security_inode_removexattr() and
security_inode_post_removexattr() arguments be the same?
> LSM_HOOK(int, 0, inode_set_acl, struct mnt_idmap *idmap,
> struct dentry *dentry, const char *acl_name, struct posix_acl *kacl)
> LSM_HOOK(int, 0, inode_get_acl, struct mnt_idmap *idmap,
--
thanks,
Mimi
On Wed, 2023-03-08 at 10:43 -0500, Mimi Zohar wrote:
> Hi Roberto,
>
> On Fri, 2023-03-03 at 19:18 +0100, Roberto Sassu wrote:
> > From: Roberto Sassu <[email protected]>
> >
> > In preparation for moving IMA and EVM to the LSM infrastructure, introduce
> > the inode_post_removexattr hook.
> >
> > Signed-off-by: Roberto Sassu <[email protected]>
> > ---
> > fs/xattr.c | 1 +
> > include/linux/lsm_hook_defs.h | 2 ++
> > include/linux/security.h | 5 +++++
> > security/security.c | 14 ++++++++++++++
> > 4 files changed, 22 insertions(+)
> >
> > diff --git a/fs/xattr.c b/fs/xattr.c
> > index 14a7eb3c8fa..10c959d9fc6 100644
> > --- a/fs/xattr.c
> > +++ b/fs/xattr.c
> > @@ -534,6 +534,7 @@ __vfs_removexattr_locked(struct mnt_idmap *idmap,
> >
> > if (!error) {
> > fsnotify_xattr(dentry);
> > + security_inode_post_removexattr(dentry, name);
> > evm_inode_post_removexattr(dentry, name);
> > }
>
> Nothing wrong with this, but other places in this function test "if
> (error) goto ...". Perhaps it is time to clean this up.
Theoretically, all 'goto out' can be replaced with 'return error'.
I would be more in favor of minimizing the changes as much as possible
to reach the main goal. But it is ok also to change the last part.
Thanks
Roberto
> >
> > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
> > index eedefbcdde3..2ae5224d967 100644
> > --- a/include/linux/lsm_hook_defs.h
> > +++ b/include/linux/lsm_hook_defs.h
> > @@ -147,6 +147,8 @@ LSM_HOOK(int, 0, inode_getxattr, struct dentry *dentry, const char *name)
> > LSM_HOOK(int, 0, inode_listxattr, struct dentry *dentry)
> > LSM_HOOK(int, 0, inode_removexattr, struct mnt_idmap *idmap,
> > struct dentry *dentry, const char *name)
> > +LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry,
> > + const char *name)
>
> @Christian should the security_inode_removexattr() and
> security_inode_post_removexattr() arguments be the same?
>
> > LSM_HOOK(int, 0, inode_set_acl, struct mnt_idmap *idmap,
> > struct dentry *dentry, const char *acl_name, struct posix_acl *kacl)
> > LSM_HOOK(int, 0, inode_get_acl, struct mnt_idmap *idmap,
On Wed, Aug 30, 2023 at 11:31:35AM +0200, Roberto Sassu wrote:
> On Wed, 2023-03-08 at 10:43 -0500, Mimi Zohar wrote:
> > Hi Roberto,
> >
> > On Fri, 2023-03-03 at 19:18 +0100, Roberto Sassu wrote:
> > > From: Roberto Sassu <[email protected]>
> > >
> > > In preparation for moving IMA and EVM to the LSM infrastructure, introduce
> > > the inode_post_removexattr hook.
> > >
> > > Signed-off-by: Roberto Sassu <[email protected]>
> > > ---
> > > fs/xattr.c | 1 +
> > > include/linux/lsm_hook_defs.h | 2 ++
> > > include/linux/security.h | 5 +++++
> > > security/security.c | 14 ++++++++++++++
> > > 4 files changed, 22 insertions(+)
> > >
> > > diff --git a/fs/xattr.c b/fs/xattr.c
> > > index 14a7eb3c8fa..10c959d9fc6 100644
> > > --- a/fs/xattr.c
> > > +++ b/fs/xattr.c
> > > @@ -534,6 +534,7 @@ __vfs_removexattr_locked(struct mnt_idmap *idmap,
> > >
> > > if (!error) {
> > > fsnotify_xattr(dentry);
> > > + security_inode_post_removexattr(dentry, name);
> > > evm_inode_post_removexattr(dentry, name);
> > > }
> >
> > Nothing wrong with this, but other places in this function test "if
> > (error) goto ...". Perhaps it is time to clean this up.
> >
> > >
> > > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
> > > index eedefbcdde3..2ae5224d967 100644
> > > --- a/include/linux/lsm_hook_defs.h
> > > +++ b/include/linux/lsm_hook_defs.h
> > > @@ -147,6 +147,8 @@ LSM_HOOK(int, 0, inode_getxattr, struct dentry *dentry, const char *name)
> > > LSM_HOOK(int, 0, inode_listxattr, struct dentry *dentry)
> > > LSM_HOOK(int, 0, inode_removexattr, struct mnt_idmap *idmap,
> > > struct dentry *dentry, const char *name)
> > > +LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry,
> > > + const char *name)
> >
> > @Christian should the security_inode_removexattr() and
> > security_inode_post_removexattr() arguments be the same?
>
> Probably this got lost.
>
> Christian, should security_inode_post_removexattr() have the idmap
> parameter as well?
Only if you call anything from any implementers of the hook that needs
access to the idmap.
On Wed, 2023-03-08 at 10:43 -0500, Mimi Zohar wrote:
> Hi Roberto,
>
> On Fri, 2023-03-03 at 19:18 +0100, Roberto Sassu wrote:
> > From: Roberto Sassu <[email protected]>
> >
> > In preparation for moving IMA and EVM to the LSM infrastructure, introduce
> > the inode_post_removexattr hook.
> >
> > Signed-off-by: Roberto Sassu <[email protected]>
> > ---
> > fs/xattr.c | 1 +
> > include/linux/lsm_hook_defs.h | 2 ++
> > include/linux/security.h | 5 +++++
> > security/security.c | 14 ++++++++++++++
> > 4 files changed, 22 insertions(+)
> >
> > diff --git a/fs/xattr.c b/fs/xattr.c
> > index 14a7eb3c8fa..10c959d9fc6 100644
> > --- a/fs/xattr.c
> > +++ b/fs/xattr.c
> > @@ -534,6 +534,7 @@ __vfs_removexattr_locked(struct mnt_idmap *idmap,
> >
> > if (!error) {
> > fsnotify_xattr(dentry);
> > + security_inode_post_removexattr(dentry, name);
> > evm_inode_post_removexattr(dentry, name);
> > }
>
> Nothing wrong with this, but other places in this function test "if
> (error) goto ...". Perhaps it is time to clean this up.
>
> >
> > diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
> > index eedefbcdde3..2ae5224d967 100644
> > --- a/include/linux/lsm_hook_defs.h
> > +++ b/include/linux/lsm_hook_defs.h
> > @@ -147,6 +147,8 @@ LSM_HOOK(int, 0, inode_getxattr, struct dentry *dentry, const char *name)
> > LSM_HOOK(int, 0, inode_listxattr, struct dentry *dentry)
> > LSM_HOOK(int, 0, inode_removexattr, struct mnt_idmap *idmap,
> > struct dentry *dentry, const char *name)
> > +LSM_HOOK(void, LSM_RET_VOID, inode_post_removexattr, struct dentry *dentry,
> > + const char *name)
>
> @Christian should the security_inode_removexattr() and
> security_inode_post_removexattr() arguments be the same?
Probably this got lost.
Christian, should security_inode_post_removexattr() have the idmap
parameter as well?
Thanks
Roberto
> > LSM_HOOK(int, 0, inode_set_acl, struct mnt_idmap *idmap,
> > struct dentry *dentry, const char *acl_name, struct posix_acl *kacl)
> > LSM_HOOK(int, 0, inode_get_acl, struct mnt_idmap *idmap,
>