diff mbox series

[bpf-next,v4,02/20] lsm: Refactor return value of LSM hook inode_need_killpriv

Message ID 20240711111908.3817636-3-xukuohai@huaweicloud.com (mailing list archive)
State Changes Requested
Delegated to: BPF
Headers show
Series Add return value range check for BPF LSM | expand

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Commit Message

Xu Kuohai July 11, 2024, 11:18 a.m. UTC 
From: Xu Kuohai <xukuohai@huawei.com>

To be consistent with most LSM hooks, convert the return value of
hook inode_need_killpriv to 0 or a negative error code.

Before:
- Both hook inode_need_killpriv and func security_inode_need_killpriv
  return > 0 if security_inode_killpriv is required, 0 if not, and < 0
  to abort the operation.

After:
- Both hook inode_need_killpriv and func security_inode_need_killpriv
  return 0 on success and a negative error code on failure.
  On success, hook inode_need_killpriv sets output param @need to true
  if security_inode_killpriv is required, and false if not. When @need
  is true, func security_inode_need_killpriv sets ATTR_KILL_PRIV flag
  in @attr; when false, it clears the flag.
  On failure, @need and @attr remains unchanged.

Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
---
 fs/attr.c                     |  5 ++---
 fs/inode.c                    |  4 +---
 include/linux/lsm_hook_defs.h |  2 +-
 include/linux/security.h      | 20 ++++++++++++++++----
 security/commoncap.c          | 12 ++++++++----
 security/security.c           | 29 ++++++++++++++++++++++++-----
 6 files changed, 52 insertions(+), 20 deletions(-)

Comments

Serge E. Hallyn July 11, 2024, 2:15 p.m. UTC | #1 
Jul 11, 2024 06:14:09 Xu Kuohai <xukuohai@huaweicloud.com>:

> From: Xu Kuohai <xukuohai@huawei.com>
>
> To be consistent with most LSM hooks, convert the return value of
> hook inode_need_killpriv to 0 or a negative error code.
>
> Before:
> - Both hook inode_need_killpriv and func security_inode_need_killpriv
>   return > 0 if security_inode_killpriv is required, 0 if not, and < 0
>   to abort the operation.
>
> After:
> - Both hook inode_need_killpriv and func security_inode_need_killpriv
>   return 0 on success and a negative error code on failure.
>   On success, hook inode_need_killpriv sets output param @need to true
>   if security_inode_killpriv is required, and false if not. When @need
>   is true, func security_inode_need_killpriv sets ATTR_KILL_PRIV flag
>   in @attr; when false, it clears the flag.
>   On failure, @need and @attr remains unchanged.
>
> Signed-off-by: Xu Kuohai <xukuohai@huawei.com>

It looks ok - though unnecessary (I'm assuming a later patch works better with this) - , but I'd be more comfortable if it was documented that any callers of the need_killpriv hook must set need to false before calling. Or if the hooks set need to false at start.


> ---
> fs/attr.c                     |  5 ++---
> fs/inode.c                    |  4 +---
> include/linux/lsm_hook_defs.h |  2 +-
> include/linux/security.h      | 20 ++++++++++++++++----
> security/commoncap.c          | 12 ++++++++----
> security/security.c           | 29 ++++++++++++++++++++++++-----
> 6 files changed, 52 insertions(+), 20 deletions(-)
>
> diff --git a/fs/attr.c b/fs/attr.c
> index 960a310581eb..aaadc721c982 100644
> --- a/fs/attr.c
> +++ b/fs/attr.c
> @@ -427,11 +427,10 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
>         attr->ia_mtime = timestamp_truncate(attr->ia_mtime, inode);
>
>     if (ia_valid & ATTR_KILL_PRIV) {
> -       error = security_inode_need_killpriv(dentry);
> +       error = security_inode_need_killpriv(dentry, &ia_valid);
>         if (error < 0)
>             return error;
> -       if (error == 0)
> -           ia_valid = attr->ia_valid &= ~ATTR_KILL_PRIV;
> +       attr->ia_valid = ia_valid;
>     }
>
>     /*
> diff --git a/fs/inode.c b/fs/inode.c
> index 3a41f83a4ba5..cd335dc3a3bc 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -2012,11 +2012,9 @@ int dentry_needs_remove_privs(struct mnt_idmap *idmap,
>         return 0;
>
>     mask = setattr_should_drop_suidgid(idmap, inode);
> -   ret = security_inode_need_killpriv(dentry);
> +   ret = security_inode_need_killpriv(dentry, &mask);
>     if (ret < 0)
>         return ret;
> -   if (ret)
> -       mask |= ATTR_KILL_PRIV;
>     return mask;
> }
>
> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
> index e6e6f8473955..964849de424b 100644
> --- a/include/linux/lsm_hook_defs.h
> +++ b/include/linux/lsm_hook_defs.h
> @@ -165,7 +165,7 @@ LSM_HOOK(int, 0, inode_remove_acl, struct mnt_idmap *idmap,
>      struct dentry *dentry, const char *acl_name)
> LSM_HOOK(void, LSM_RET_VOID, inode_post_remove_acl, struct mnt_idmap *idmap,
>      struct dentry *dentry, const char *acl_name)
> -LSM_HOOK(int, 0, inode_need_killpriv, struct dentry *dentry)
> +LSM_HOOK(int, 0, inode_need_killpriv, struct dentry *dentry, bool *need)
> LSM_HOOK(int, 0, inode_killpriv, struct mnt_idmap *idmap,
>      struct dentry *dentry)
> LSM_HOOK(int, -EOPNOTSUPP, inode_getsecurity, struct mnt_idmap *idmap,
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 454f96307cb9..1614ef5b2dd2 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -161,7 +161,7 @@ int cap_inode_setxattr(struct dentry *dentry, const char *name,
>                const void *value, size_t size, int flags);
> int cap_inode_removexattr(struct mnt_idmap *idmap,
>               struct dentry *dentry, const char *name);
> -int cap_inode_need_killpriv(struct dentry *dentry);
> +int cap_inode_need_killpriv(struct dentry *dentry, bool *need);
> int cap_inode_killpriv(struct mnt_idmap *idmap, struct dentry *dentry);
> int cap_inode_getsecurity(struct mnt_idmap *idmap,
>               struct inode *inode, const char *name, void **buffer,
> @@ -389,7 +389,7 @@ 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_need_killpriv(struct dentry *dentry, int *attr);
> int security_inode_killpriv(struct mnt_idmap *idmap, struct dentry *dentry);
> int security_inode_getsecurity(struct mnt_idmap *idmap,
>                    struct inode *inode, const char *name,
> @@ -971,9 +971,21 @@ static inline void security_inode_post_removexattr(struct dentry *dentry,
>                            const char *name)
> { }
>
> -static inline int security_inode_need_killpriv(struct dentry *dentry)
> +static inline int security_inode_need_killpriv(struct dentry *dentry, int *attr)
> {
> -   return cap_inode_need_killpriv(dentry);
> +   int rc;
> +   bool need = false;
> +
> +   rc = cap_inode_need_killpriv(dentry, &need);
> +   if (rc < 0)
> +       return rc;
> +
> +   if (need)
> +       *attr |= ATTR_KILL_PRIV;
> +   else
> +       *attr &= ~ATTR_KILL_PRIV;
> +
> +   return 0;
> }
>
> static inline int security_inode_killpriv(struct mnt_idmap *idmap,
> diff --git a/security/commoncap.c b/security/commoncap.c
> index cefad323a0b1..17d6188d22cf 100644
> --- a/security/commoncap.c
> +++ b/security/commoncap.c
> @@ -286,21 +286,25 @@ int cap_capset(struct cred *new,
> /**
>   * cap_inode_need_killpriv - Determine if inode change affects privileges
>   * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV
> + * @need: If inode_killpriv() is needed
>   *
>   * Determine if an inode having a change applied that's marked ATTR_KILL_PRIV
>   * affects the security markings on that inode, and if it is, should
>   * inode_killpriv() be invoked or the change rejected.
>   *
> - * Return: 1 if security.capability has a value, meaning inode_killpriv()
> - * is required, 0 otherwise, meaning inode_killpriv() is not required.
> + * Return: Always returns 0. If security.capability has a value, meaning
> + * inode_killpriv() is required, @need is set to true.
>   */
> -int cap_inode_need_killpriv(struct dentry *dentry)
> +int cap_inode_need_killpriv(struct dentry *dentry, bool *need)
> {
>     struct inode *inode = d_backing_inode(dentry);
>     int error;
>
>     error = __vfs_getxattr(dentry, inode, XATTR_NAME_CAPS, NULL, 0);
> -   return error > 0;
> +   if (error > 0)
> +       *need = true;
> +
> +   return 0;
> }
>
> /**
> diff --git a/security/security.c b/security/security.c
> index 3475f0cab3da..a4abcd86eb36 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -2490,17 +2490,36 @@ void security_inode_post_removexattr(struct dentry *dentry, const char *name)
> /**
>   * security_inode_need_killpriv() - Check if security_inode_killpriv() required
>   * @dentry: associated dentry
> + * @attr: attribute flags
>   *
>   * Called when an inode has been changed to determine if
>   * security_inode_killpriv() should be called.
>   *
> - * Return: Return <0 on error to abort the inode change operation, return 0 if
> - *         security_inode_killpriv() does not need to be called, return >0 if
> - *         security_inode_killpriv() does need to be called.
> + * Return: Return 0 on success, negative error code on failure.
> + *         On success, set ATTR_KILL_PRIV flag in @attr when @need is true,
> + *         clears it when false.
>   */
> -int security_inode_need_killpriv(struct dentry *dentry)
> +int security_inode_need_killpriv(struct dentry *dentry, int *attr)
> {
> -   return call_int_hook(inode_need_killpriv, dentry);
> +   int rc;
> +   bool need = false;
> +   struct security_hook_list *hp;
> +
> +   hlist_for_each_entry(hp, &security_hook_heads.inode_need_killpriv,
> +                list) {
> +       rc = hp->hook.inode_need_killpriv(dentry, &need);
> +       if (rc < 0)
> +           return rc;
> +       if (need)
> +           break;
> +   }
> +
> +   if (need)
> +       *attr |= ATTR_KILL_PRIV;
> +   else
> +       *attr &= ~ATTR_KILL_PRIV;
> +
> +   return 0;
> }
>
> /**
> --
> 2.30.2
Xu Kuohai July 13, 2024, 8:06 a.m. UTC | #2 
On 7/11/2024 10:15 PM, Serge Hallyn wrote:
> Jul 11, 2024 06:14:09 Xu Kuohai <xukuohai@huaweicloud.com>:
> 
>> From: Xu Kuohai <xukuohai@huawei.com>
>>
>> To be consistent with most LSM hooks, convert the return value of
>> hook inode_need_killpriv to 0 or a negative error code.
>>
>> Before:
>> - Both hook inode_need_killpriv and func security_inode_need_killpriv
>>    return > 0 if security_inode_killpriv is required, 0 if not, and < 0
>>    to abort the operation.
>>
>> After:
>> - Both hook inode_need_killpriv and func security_inode_need_killpriv
>>    return 0 on success and a negative error code on failure.
>>    On success, hook inode_need_killpriv sets output param @need to true
>>    if security_inode_killpriv is required, and false if not. When @need
>>    is true, func security_inode_need_killpriv sets ATTR_KILL_PRIV flag
>>    in @attr; when false, it clears the flag.
>>    On failure, @need and @attr remains unchanged.
>>
>> Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
> 
> It looks ok - though unnecessary (I'm assuming a later patch works better with this) - , but I'd be more comfortable if it was documented that any callers of the need_killpriv hook must set need to false before calling. Or if the hooks set need to false at start.
> 
>

I believe this is the only patch in the set that modifies 'inode_need_killpriv'.
I'll add an explanation for the initial value of '@need'.
Thanks.
Paul Moore July 19, 2024, 2:08 a.m. UTC | #3 
On Jul 11, 2024 Xu Kuohai <xukuohai@huaweicloud.com> wrote:
> 
> To be consistent with most LSM hooks, convert the return value of
> hook inode_need_killpriv to 0 or a negative error code.
> 
> Before:
> - Both hook inode_need_killpriv and func security_inode_need_killpriv
>   return > 0 if security_inode_killpriv is required, 0 if not, and < 0
>   to abort the operation.
> 
> After:
> - Both hook inode_need_killpriv and func security_inode_need_killpriv
>   return 0 on success and a negative error code on failure.
>   On success, hook inode_need_killpriv sets output param @need to true
>   if security_inode_killpriv is required, and false if not. When @need
>   is true, func security_inode_need_killpriv sets ATTR_KILL_PRIV flag
>   in @attr; when false, it clears the flag.
>   On failure, @need and @attr remains unchanged.
> 
> Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
> ---
>  fs/attr.c                     |  5 ++---
>  fs/inode.c                    |  4 +---
>  include/linux/lsm_hook_defs.h |  2 +-
>  include/linux/security.h      | 20 ++++++++++++++++----
>  security/commoncap.c          | 12 ++++++++----
>  security/security.c           | 29 ++++++++++++++++++++++++-----
>  6 files changed, 52 insertions(+), 20 deletions(-)

In general I think a lot of these changes are a good improvement, thank
you very much for the time and effort you've spent on this.  However,
I'm not in favor of passing the new hook parameter as a way of reducing
the number of states represented by the security_inode_killpriv() return
value.  This particular hook may need to remain as one of the odd special
cases.

> diff --git a/fs/attr.c b/fs/attr.c
> index 960a310581eb..aaadc721c982 100644
> --- a/fs/attr.c
> +++ b/fs/attr.c
> @@ -427,11 +427,10 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
>  		attr->ia_mtime = timestamp_truncate(attr->ia_mtime, inode);
>  
>  	if (ia_valid & ATTR_KILL_PRIV) {
> -		error = security_inode_need_killpriv(dentry);
> +		error = security_inode_need_killpriv(dentry, &ia_valid);
>  		if (error < 0)
>  			return error;
> -		if (error == 0)
> -			ia_valid = attr->ia_valid &= ~ATTR_KILL_PRIV;
> +		attr->ia_valid = ia_valid;
>  	}
>  
>  	/*
> diff --git a/fs/inode.c b/fs/inode.c
> index 3a41f83a4ba5..cd335dc3a3bc 100644
> --- a/fs/inode.c
> +++ b/fs/inode.c
> @@ -2012,11 +2012,9 @@ int dentry_needs_remove_privs(struct mnt_idmap *idmap,
>  		return 0;
>  
>  	mask = setattr_should_drop_suidgid(idmap, inode);
> -	ret = security_inode_need_killpriv(dentry);
> +	ret = security_inode_need_killpriv(dentry, &mask);
>  	if (ret < 0)
>  		return ret;
> -	if (ret)
> -		mask |= ATTR_KILL_PRIV;
>  	return mask;
>  }
>  
> diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
> index e6e6f8473955..964849de424b 100644
> --- a/include/linux/lsm_hook_defs.h
> +++ b/include/linux/lsm_hook_defs.h
> @@ -165,7 +165,7 @@ LSM_HOOK(int, 0, inode_remove_acl, struct mnt_idmap *idmap,
>  	 struct dentry *dentry, const char *acl_name)
>  LSM_HOOK(void, LSM_RET_VOID, inode_post_remove_acl, struct mnt_idmap *idmap,
>  	 struct dentry *dentry, const char *acl_name)
> -LSM_HOOK(int, 0, inode_need_killpriv, struct dentry *dentry)
> +LSM_HOOK(int, 0, inode_need_killpriv, struct dentry *dentry, bool *need)
>  LSM_HOOK(int, 0, inode_killpriv, struct mnt_idmap *idmap,
>  	 struct dentry *dentry)
>  LSM_HOOK(int, -EOPNOTSUPP, inode_getsecurity, struct mnt_idmap *idmap,
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 454f96307cb9..1614ef5b2dd2 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -161,7 +161,7 @@ int cap_inode_setxattr(struct dentry *dentry, const char *name,
>  		       const void *value, size_t size, int flags);
>  int cap_inode_removexattr(struct mnt_idmap *idmap,
>  			  struct dentry *dentry, const char *name);
> -int cap_inode_need_killpriv(struct dentry *dentry);
> +int cap_inode_need_killpriv(struct dentry *dentry, bool *need);
>  int cap_inode_killpriv(struct mnt_idmap *idmap, struct dentry *dentry);
>  int cap_inode_getsecurity(struct mnt_idmap *idmap,
>  			  struct inode *inode, const char *name, void **buffer,
> @@ -389,7 +389,7 @@ 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_need_killpriv(struct dentry *dentry, int *attr);
>  int security_inode_killpriv(struct mnt_idmap *idmap, struct dentry *dentry);
>  int security_inode_getsecurity(struct mnt_idmap *idmap,
>  			       struct inode *inode, const char *name,
> @@ -971,9 +971,21 @@ static inline void security_inode_post_removexattr(struct dentry *dentry,
>  						   const char *name)
>  { }
>  
> -static inline int security_inode_need_killpriv(struct dentry *dentry)
> +static inline int security_inode_need_killpriv(struct dentry *dentry, int *attr)
>  {
> -	return cap_inode_need_killpriv(dentry);
> +	int rc;
> +	bool need = false;
> +
> +	rc = cap_inode_need_killpriv(dentry, &need);
> +	if (rc < 0)
> +		return rc;
> +
> +	if (need)
> +		*attr |= ATTR_KILL_PRIV;
> +	else
> +		*attr &= ~ATTR_KILL_PRIV;
> +
> +	return 0;
>  }
>  
>  static inline int security_inode_killpriv(struct mnt_idmap *idmap,
> diff --git a/security/commoncap.c b/security/commoncap.c
> index cefad323a0b1..17d6188d22cf 100644
> --- a/security/commoncap.c
> +++ b/security/commoncap.c
> @@ -286,21 +286,25 @@ int cap_capset(struct cred *new,
>  /**
>   * cap_inode_need_killpriv - Determine if inode change affects privileges
>   * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV
> + * @need: If inode_killpriv() is needed
>   *
>   * Determine if an inode having a change applied that's marked ATTR_KILL_PRIV
>   * affects the security markings on that inode, and if it is, should
>   * inode_killpriv() be invoked or the change rejected.
>   *
> - * Return: 1 if security.capability has a value, meaning inode_killpriv()
> - * is required, 0 otherwise, meaning inode_killpriv() is not required.
> + * Return: Always returns 0. If security.capability has a value, meaning
> + * inode_killpriv() is required, @need is set to true.
>   */
> -int cap_inode_need_killpriv(struct dentry *dentry)
> +int cap_inode_need_killpriv(struct dentry *dentry, bool *need)
>  {
>  	struct inode *inode = d_backing_inode(dentry);
>  	int error;
>  
>  	error = __vfs_getxattr(dentry, inode, XATTR_NAME_CAPS, NULL, 0);
> -	return error > 0;
> +	if (error > 0)
> +		*need = true;
> +
> +	return 0;
>  }
>  
>  /**
> diff --git a/security/security.c b/security/security.c
> index 3475f0cab3da..a4abcd86eb36 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -2490,17 +2490,36 @@ void security_inode_post_removexattr(struct dentry *dentry, const char *name)
>  /**
>   * security_inode_need_killpriv() - Check if security_inode_killpriv() required
>   * @dentry: associated dentry
> + * @attr: attribute flags
>   *
>   * Called when an inode has been changed to determine if
>   * security_inode_killpriv() should be called.
>   *
> - * Return: Return <0 on error to abort the inode change operation, return 0 if
> - *         security_inode_killpriv() does not need to be called, return >0 if
> - *         security_inode_killpriv() does need to be called.
> + * Return: Return 0 on success, negative error code on failure.
> + *         On success, set ATTR_KILL_PRIV flag in @attr when @need is true,
> + *         clears it when false.
>   */
> -int security_inode_need_killpriv(struct dentry *dentry)
> +int security_inode_need_killpriv(struct dentry *dentry, int *attr)
>  {
> -	return call_int_hook(inode_need_killpriv, dentry);
> +	int rc;
> +	bool need = false;
> +	struct security_hook_list *hp;
> +
> +	hlist_for_each_entry(hp, &security_hook_heads.inode_need_killpriv,
> +			     list) {
> +		rc = hp->hook.inode_need_killpriv(dentry, &need);
> +		if (rc < 0)
> +			return rc;
> +		if (need)
> +			break;
> +	}
> +
> +	if (need)
> +		*attr |= ATTR_KILL_PRIV;
> +	else
> +		*attr &= ~ATTR_KILL_PRIV;
> +
> +	return 0;
>  }
>  
>  /**
> -- 
> 2.30.2

--
paul-moore.com
Xu Kuohai July 20, 2024, 9:27 a.m. UTC | #4 
On 7/19/2024 10:08 AM, Paul Moore wrote:
> On Jul 11, 2024 Xu Kuohai <xukuohai@huaweicloud.com> wrote:
>>
>> To be consistent with most LSM hooks, convert the return value of
>> hook inode_need_killpriv to 0 or a negative error code.
>>
>> Before:
>> - Both hook inode_need_killpriv and func security_inode_need_killpriv
>>    return > 0 if security_inode_killpriv is required, 0 if not, and < 0
>>    to abort the operation.
>>
>> After:
>> - Both hook inode_need_killpriv and func security_inode_need_killpriv
>>    return 0 on success and a negative error code on failure.
>>    On success, hook inode_need_killpriv sets output param @need to true
>>    if security_inode_killpriv is required, and false if not. When @need
>>    is true, func security_inode_need_killpriv sets ATTR_KILL_PRIV flag
>>    in @attr; when false, it clears the flag.
>>    On failure, @need and @attr remains unchanged.
>>
>> Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
>> ---
>>   fs/attr.c                     |  5 ++---
>>   fs/inode.c                    |  4 +---
>>   include/linux/lsm_hook_defs.h |  2 +-
>>   include/linux/security.h      | 20 ++++++++++++++++----
>>   security/commoncap.c          | 12 ++++++++----
>>   security/security.c           | 29 ++++++++++++++++++++++++-----
>>   6 files changed, 52 insertions(+), 20 deletions(-)
> 
> In general I think a lot of these changes are a good improvement, thank
> you very much for the time and effort you've spent on this.  However,
> I'm not in favor of passing the new hook parameter as a way of reducing
> the number of states represented by the security_inode_killpriv() return
> value.  This particular hook may need to remain as one of the odd special
> cases.
> 

I learned from previous discussions [1] to use a new output parameter to store
odd return values. Actually, I am not in favor of this method either, especially
since it requires extra work to enable BPF to access the output parameter. I
think we could just keep it as-is.

[1] https://lore.kernel.org/bpf/CAHC9VhQ_sTmoXwQ_AVfjTYQe4KR-uTnksPVfsei5JZ+VDJBQkA@mail.gmail.com/
diff mbox series

Patch

diff --git a/fs/attr.c b/fs/attr.c
index 960a310581eb..aaadc721c982 100644
--- a/fs/attr.c
+++ b/fs/attr.c
@@ -427,11 +427,10 @@  int notify_change(struct mnt_idmap *idmap, struct dentry *dentry,
 		attr->ia_mtime = timestamp_truncate(attr->ia_mtime, inode);
 
 	if (ia_valid & ATTR_KILL_PRIV) {
-		error = security_inode_need_killpriv(dentry);
+		error = security_inode_need_killpriv(dentry, &ia_valid);
 		if (error < 0)
 			return error;
-		if (error == 0)
-			ia_valid = attr->ia_valid &= ~ATTR_KILL_PRIV;
+		attr->ia_valid = ia_valid;
 	}
 
 	/*
diff --git a/fs/inode.c b/fs/inode.c
index 3a41f83a4ba5..cd335dc3a3bc 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -2012,11 +2012,9 @@  int dentry_needs_remove_privs(struct mnt_idmap *idmap,
 		return 0;
 
 	mask = setattr_should_drop_suidgid(idmap, inode);
-	ret = security_inode_need_killpriv(dentry);
+	ret = security_inode_need_killpriv(dentry, &mask);
 	if (ret < 0)
 		return ret;
-	if (ret)
-		mask |= ATTR_KILL_PRIV;
 	return mask;
 }
 
diff --git a/include/linux/lsm_hook_defs.h b/include/linux/lsm_hook_defs.h
index e6e6f8473955..964849de424b 100644
--- a/include/linux/lsm_hook_defs.h
+++ b/include/linux/lsm_hook_defs.h
@@ -165,7 +165,7 @@  LSM_HOOK(int, 0, inode_remove_acl, struct mnt_idmap *idmap,
 	 struct dentry *dentry, const char *acl_name)
 LSM_HOOK(void, LSM_RET_VOID, inode_post_remove_acl, struct mnt_idmap *idmap,
 	 struct dentry *dentry, const char *acl_name)
-LSM_HOOK(int, 0, inode_need_killpriv, struct dentry *dentry)
+LSM_HOOK(int, 0, inode_need_killpriv, struct dentry *dentry, bool *need)
 LSM_HOOK(int, 0, inode_killpriv, struct mnt_idmap *idmap,
 	 struct dentry *dentry)
 LSM_HOOK(int, -EOPNOTSUPP, inode_getsecurity, struct mnt_idmap *idmap,
diff --git a/include/linux/security.h b/include/linux/security.h
index 454f96307cb9..1614ef5b2dd2 100644
--- a/include/linux/security.h
+++ b/include/linux/security.h
@@ -161,7 +161,7 @@  int cap_inode_setxattr(struct dentry *dentry, const char *name,
 		       const void *value, size_t size, int flags);
 int cap_inode_removexattr(struct mnt_idmap *idmap,
 			  struct dentry *dentry, const char *name);
-int cap_inode_need_killpriv(struct dentry *dentry);
+int cap_inode_need_killpriv(struct dentry *dentry, bool *need);
 int cap_inode_killpriv(struct mnt_idmap *idmap, struct dentry *dentry);
 int cap_inode_getsecurity(struct mnt_idmap *idmap,
 			  struct inode *inode, const char *name, void **buffer,
@@ -389,7 +389,7 @@  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_need_killpriv(struct dentry *dentry, int *attr);
 int security_inode_killpriv(struct mnt_idmap *idmap, struct dentry *dentry);
 int security_inode_getsecurity(struct mnt_idmap *idmap,
 			       struct inode *inode, const char *name,
@@ -971,9 +971,21 @@  static inline void security_inode_post_removexattr(struct dentry *dentry,
 						   const char *name)
 { }
 
-static inline int security_inode_need_killpriv(struct dentry *dentry)
+static inline int security_inode_need_killpriv(struct dentry *dentry, int *attr)
 {
-	return cap_inode_need_killpriv(dentry);
+	int rc;
+	bool need = false;
+
+	rc = cap_inode_need_killpriv(dentry, &need);
+	if (rc < 0)
+		return rc;
+
+	if (need)
+		*attr |= ATTR_KILL_PRIV;
+	else
+		*attr &= ~ATTR_KILL_PRIV;
+
+	return 0;
 }
 
 static inline int security_inode_killpriv(struct mnt_idmap *idmap,
diff --git a/security/commoncap.c b/security/commoncap.c
index cefad323a0b1..17d6188d22cf 100644
--- a/security/commoncap.c
+++ b/security/commoncap.c
@@ -286,21 +286,25 @@  int cap_capset(struct cred *new,
 /**
  * cap_inode_need_killpriv - Determine if inode change affects privileges
  * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV
+ * @need: If inode_killpriv() is needed
  *
  * Determine if an inode having a change applied that's marked ATTR_KILL_PRIV
  * affects the security markings on that inode, and if it is, should
  * inode_killpriv() be invoked or the change rejected.
  *
- * Return: 1 if security.capability has a value, meaning inode_killpriv()
- * is required, 0 otherwise, meaning inode_killpriv() is not required.
+ * Return: Always returns 0. If security.capability has a value, meaning
+ * inode_killpriv() is required, @need is set to true.
  */
-int cap_inode_need_killpriv(struct dentry *dentry)
+int cap_inode_need_killpriv(struct dentry *dentry, bool *need)
 {
 	struct inode *inode = d_backing_inode(dentry);
 	int error;
 
 	error = __vfs_getxattr(dentry, inode, XATTR_NAME_CAPS, NULL, 0);
-	return error > 0;
+	if (error > 0)
+		*need = true;
+
+	return 0;
 }
 
 /**
diff --git a/security/security.c b/security/security.c
index 3475f0cab3da..a4abcd86eb36 100644
--- a/security/security.c
+++ b/security/security.c
@@ -2490,17 +2490,36 @@  void security_inode_post_removexattr(struct dentry *dentry, const char *name)
 /**
  * security_inode_need_killpriv() - Check if security_inode_killpriv() required
  * @dentry: associated dentry
+ * @attr: attribute flags
  *
  * Called when an inode has been changed to determine if
  * security_inode_killpriv() should be called.
  *
- * Return: Return <0 on error to abort the inode change operation, return 0 if
- *         security_inode_killpriv() does not need to be called, return >0 if
- *         security_inode_killpriv() does need to be called.
+ * Return: Return 0 on success, negative error code on failure.
+ *         On success, set ATTR_KILL_PRIV flag in @attr when @need is true,
+ *         clears it when false.
  */
-int security_inode_need_killpriv(struct dentry *dentry)
+int security_inode_need_killpriv(struct dentry *dentry, int *attr)
 {
-	return call_int_hook(inode_need_killpriv, dentry);
+	int rc;
+	bool need = false;
+	struct security_hook_list *hp;
+
+	hlist_for_each_entry(hp, &security_hook_heads.inode_need_killpriv,
+			     list) {
+		rc = hp->hook.inode_need_killpriv(dentry, &need);
+		if (rc < 0)
+			return rc;
+		if (need)
+			break;
+	}
+
+	if (need)
+		*attr |= ATTR_KILL_PRIV;
+	else
+		*attr &= ~ATTR_KILL_PRIV;
+
+	return 0;
 }
 
 /**