How to verify if a given user has read access to a file?

Try this. Directory.GetAcessControl(path)

var writeAllow = false;

var writeDeny = false;

var accessControlList = Directory.GetAccessControl(path);

if (accessControlList == null)

return false;

var accessRules = accessControlList.GetAccessRules(true, true,

typeof(System.Security.Principal.SecurityIdentifier));

if (accessRules ==null)

return false;

foreach (FileSystemAccessRule rule in accessRules)

{

if ((FileSystemRights.Write & rule.FileSystemRights) != FileSystemRights.Write)

continue;

if (rule.AccessControlType == AccessControlType.Allow)

writeAllow = true;

else if (rule.AccessControlType == AccessControlType.Deny)

writeDeny = true;

}