GetSecurityInfo function (aclapi.h)

Article
10/13/2021

The GetSecurityInfo function retrieves a copy of the security descriptor for an object specified by a handle.

Syntax

DWORD GetSecurityInfo(
  [in]            HANDLE               handle,
  [in]            SE_OBJECT_TYPE       ObjectType,
  [in]            SECURITY_INFORMATION SecurityInfo,
  [out, optional] PSID                 *ppsidOwner,
  [out, optional] PSID                 *ppsidGroup,
  [out, optional] PACL                 *ppDacl,
  [out, optional] PACL                 *ppSacl,
  [out, optional] PSECURITY_DESCRIPTOR *ppSecurityDescriptor
);

Parameters

[in] handle

A handle to the object from which to retrieve security information.

[in] ObjectType

SE_OBJECT_TYPE enumeration value that indicates the type of object.

[in] SecurityInfo

A set of bit flags that indicate the type of security information to retrieve. This parameter can be a combination of the SECURITY_INFORMATION bit flags.

[out, optional] ppsidOwner

A pointer to a variable that receives a pointer to the owner SID in the security descriptor returned in ppSecurityDescriptor. The returned pointer is valid only if you set the OWNER_SECURITY_INFORMATION flag. This parameter can be NULL if you do not need the owner SID.

[out, optional] ppsidGroup

A pointer to a variable that receives a pointer to the primary group SID in the returned security descriptor. The returned pointer is valid only if you set the GROUP_SECURITY_INFORMATION flag. This parameter can be NULL if you do not need the group SID.

[out, optional] ppDacl

A pointer to a variable that receives a pointer to the DACL in the returned security descriptor. The returned pointer is valid only if you set the DACL_SECURITY_INFORMATION flag. This parameter can be NULL if you do not need the DACL.

[out, optional] ppSacl

A pointer to a variable that receives a pointer to the SACL in the returned security descriptor. The returned pointer is valid only if you set the SACL_SECURITY_INFORMATION flag. This parameter can be NULL if you do not need the SACL.

[out, optional] ppSecurityDescriptor

A pointer to a variable that receives a pointer to the security descriptor of the object. When you have finished using the pointer, free the returned buffer by calling the LocalFree function.

This parameter is required if any one of the ppsidOwner, ppsidGroup, ppDacl, or ppSacl parameters is not NULL.

Return value

If the function succeeds, the return value is ERROR_SUCCESS.

If the function fails, the return value is a nonzero error code defined in WinError.h.

Remarks

If the ppsidOwner, ppsidGroup, ppDacl, and ppSacl parameters are non-NULL, and the SecurityInfo parameter specifies that they be retrieved from the object, those parameters will point to the corresponding parameters in the security descriptor returned in ppSecurityDescriptor.

To read the owner, group, or DACL from the object's security descriptor, the calling process must have been granted READ_CONTROL access when the handle was opened. To get READ_CONTROL access, the caller must be the owner of the object or the object's DACL must grant the access.

To read the SACL from the security descriptor, the calling process must have been granted ACCESS_SYSTEM_SECURITY access when the handle was opened. The proper way to get this access is to enable the SE_SECURITY_NAME privilege in the caller's current token, open the handle for ACCESS_SYSTEM_SECURITY access, and then disable the privilege. For information about the security implications of enabling privileges, see Running with Special Privileges.

You can use the GetSecurityInfo function with the following types of objects:

Local or remote files or directories on an NTFS file system
Named pipes
Local or remote printers
Local or remote Windows services
Network shares
Registry keys
Semaphores, events, mutexes, and waitable timers
Processes, threads, jobs, and file-mapping objects
Interactive service window stations and desktops
Directory service objects

This function does not handle race conditions. If your thread calls this function at the approximate time that another thread changes the object's security descriptor, then this function could fail.

Examples

For an example that uses this function, see Finding the Owner of a File Object.

Requirements

Requirement	Value
Minimum supported client	Windows XP [desktop apps \| UWP apps]
Minimum supported server	Windows Server 2003 [desktop apps \| UWP apps]
Target Platform	Windows
Header	aclapi.h
Library	Advapi32.lib
DLL	Advapi32.dll

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