2023-03-03 18:22:05

by Roberto Sassu

Subject: [PATCH 14/28] security: Introduce inode_post_setattr hook

From: Roberto Sassu <[email protected]>

In preparation for moving IMA and EVM to the LSM infrastructure, introduce
the inode_post_setattr hook.

Signed-off-by: Roberto Sassu <[email protected]>
---
fs/attr.c | 1 +
include/linux/lsm_hook_defs.h | 2 ++
include/linux/security.h | 7 +++++++
security/security.c | 16 ++++++++++++++++
4 files changed, 26 insertions(+)

diff --git a/fs/attr.c b/fs/attr.c
index da45cf01be6..343d6d62435 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -485,6 +485,7 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry,

if (!error) {
fsnotify_change(dentry, ia_valid);
+ security_inode_post_setattr(idmap, dentry, ia_valid);
ima_inode_post_setattr(idmap, dentry, ia_valid);
evm_inode_post_setattr(idmap, dentry, ia_valid);
}
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index 4372a6b2632..eedefbcdde3 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -135,6 +135,8 @@ LSM_HOOK(int, 0, inode_follow_link, struct dentry *dentry, struct inode *inode,
LSM_HOOK(int, 0, inode_permission, struct inode *inode, int mask)
LSM_HOOK(int, 0, inode_setattr, struct mnt_idmap *idmap, struct dentry *dentry,
struct iattr *attr)
+LSM_HOOK(void, LSM_RET_VOID, inode_post_setattr, struct mnt_idmap *idmap,
+ struct dentry *dentry, int ia_valid)
LSM_HOOK(int, 0, inode_getattr, const struct path *path)
LSM_HOOK(int, 0, inode_setxattr, struct mnt_idmap *idmap,
struct dentry *dentry, const char *name, const void *value,
diff --git a/include/linux/security.h b/include/linux/security.h
index cd23221ce9e..64224216f6c 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -354,6 +354,8 @@ int security_inode_follow_link(struct dentry *dentry, struct inode *inode,
int security_inode_permission(struct inode *inode, int mask);
int security_inode_setattr(struct mnt_idmap *idmap,
struct dentry *dentry, struct iattr *attr);
+void security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ int ia_valid);
int security_inode_getattr(const struct path *path);
int security_inode_setxattr(struct mnt_idmap *idmap,
struct dentry *dentry, const char *name,
@@ -855,6 +857,11 @@ static inline int security_inode_setattr(struct mnt_idmap *idmap,
return 0;
}

+static inline void
+security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ int ia_valid)
+{ }
+
static inline int security_inode_getattr(const struct path *path)
{
return 0;
diff --git a/security/security.c b/security/security.c
index f7fe252e9d3..2dbf225f5d8 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2190,6 +2190,22 @@ int security_inode_getattr(const struct path *path)
return call_int_hook(inode_getattr, 0, path);
}

+/**
+ * security_inode_post_setattr() - Update the inode after a setattr operation
+ * @idmap: idmap of the mount
+ * @dentry: file
+ * @ia_valid: file attributes set
+ *
+ * Update inode security field after successful setting file attributes.
+ */
+void security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
+ int ia_valid)
+{
+ if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
+ return;
+ call_void_hook(inode_post_setattr, idmap, dentry, ia_valid);
+}
+
/**
* security_inode_setxattr() - Check if setting file xattrs is allowed
* @idmap: idmap of the mount
--
2.25.1

2023-03-06 18:14:22

by Stefan Berger

Subject: Re: [PATCH 14/28] security: Introduce inode_post_setattr hook

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_setattr hook.
>
> Signed-off-by: Roberto Sassu <[email protected]>

Reviewed-by: Stefan Berger <[email protected]>

2023-03-08 15:20:05

by Mimi Zohar

Subject: Re: [PATCH 14/28] security: Introduce inode_post_setattr hook

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_setattr hook.
>
> Signed-off-by: Roberto Sassu <[email protected]>

Other than the one minor comment below,

Reviewed-by: Mimi Zohar <[email protected]>
> ---
> fs/attr.c | 1 +
> include/linux/lsm_hook_defs.h | 2 ++
> include/linux/security.h | 7 +++++++
> security/security.c | 16 ++++++++++++++++
> 4 files changed, 26 insertions(+)
>
> diff --git a/fs/attr.c b/fs/attr.c
> index da45cf01be6..343d6d62435 100644
> --- a/fs/attr.c
> +++ b/fs/attr.c
> @@ -485,6 +485,7 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
>
> if (!error) {
> fsnotify_change(dentry, ia_valid);
> + security_inode_post_setattr(idmap, dentry, ia_valid);
> ima_inode_post_setattr(idmap, dentry, ia_valid);
> evm_inode_post_setattr(idmap, dentry, ia_valid);
> }
> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
> index 4372a6b2632..eedefbcdde3 100644
> --- a/include/linux/lsm_hook_defs.h
> +++ b/include/linux/lsm_hook_defs.h
> @@ -135,6 +135,8 @@ LSM_HOOK(int, 0, inode_follow_link, struct dentry *dentry, struct inode *inode,
> LSM_HOOK(int, 0, inode_permission, struct inode *inode, int mask)
> LSM_HOOK(int, 0, inode_setattr, struct mnt_idmap *idmap, struct dentry *dentry,
> struct iattr *attr)
> +LSM_HOOK(void, LSM_RET_VOID, inode_post_setattr, struct mnt_idmap *idmap,
> + struct dentry *dentry, int ia_valid)
> LSM_HOOK(int, 0, inode_getattr, const struct path *path)
> LSM_HOOK(int, 0, inode_setxattr, struct mnt_idmap *idmap,
> struct dentry *dentry, const char *name, const void *value,
> diff --git a/include/linux/security.h b/include/linux/security.h
> index cd23221ce9e..64224216f6c 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -354,6 +354,8 @@ int security_inode_follow_link(struct dentry *dentry, struct inode *inode,
> int security_inode_permission(struct inode *inode, int mask);
> int security_inode_setattr(struct mnt_idmap *idmap,
> struct dentry *dentry, struct iattr *attr);
> +void security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
> + int ia_valid);
> int security_inode_getattr(const struct path *path);
> int security_inode_setxattr(struct mnt_idmap *idmap,
> struct dentry *dentry, const char *name,
> @@ -855,6 +857,11 @@ static inline int security_inode_setattr(struct mnt_idmap *idmap,
> return 0;
> }
>
> +static inline void
> +security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
> + int ia_valid)
> +{ }
> +
> static inline int security_inode_getattr(const struct path *path)
> {
> return 0;
> diff --git a/security/security.c b/security/security.c
> index f7fe252e9d3..2dbf225f5d8 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -2190,6 +2190,22 @@ int security_inode_getattr(const struct path *path)
> return call_int_hook(inode_getattr, 0, path);
> }
>

Like the definitions, move the security_inode_post_setattr() to after
security_inode_setattr().

> +/**
> + * security_inode_post_setattr() - Update the inode after a setattr operation
> + * @idmap: idmap of the mount
> + * @dentry: file
> + * @ia_valid: file attributes set
> + *
> + * Update inode security field after successful setting file attributes.
> + */
> +void security_inode_post_setattr(struct mnt_idmap *idmap, struct dentry *entry,
> + int ia_valid)
> +{
> + if (unlikely(IS_PRIVATE(d_backing_inode(dentry))))
> + return;
> + call_void_hook(inode_post_setattr, idmap, dentry, ia_valid);
> +}
> +
> /**
> * security_inode_setxattr() - Check if setting file xattrs is allowed
> * @idmap: idmap of the mounth

--
thanks,

Mimi