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all: imp code, docs

This commit is contained in:
Eugene Burkov 2024-11-28 19:21:03 +03:00
parent c076c93669
commit 3a5b6aced9
6 changed files with 83 additions and 34 deletions
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3
CHANGELOG.md
View File

@ -27,6 +27,9 @@ NOTE: Add new changes BELOW THIS COMMENT.
### Security
- The permission check and migration on Windows has been fixed to use the
Windows security model more accurately ([#7400]).
- Go version has been updated to prevent the possibility of exploiting the Go
vulnerabilities fixed in [1.23.3][go-1.23.3].

2
internal/aghrenameio/renameio_windows.go
View File

@ -62,6 +62,8 @@ func newPendingFile(filePath string, mode fs.FileMode) (f PendingFile, err error
return nil, fmt.Errorf("opening pending file: %w", err)
}
// TODO(e.burkov): The [os.Chmod] implementation is useless on Windows,
// investigate if it can be removed.
err = os.Chmod(file.Name(), mode)
if err != nil {
return nil, fmt.Errorf("preparing pending file: %w", err)

7
internal/permcheck/check_windows.go
View File

@ -11,6 +11,11 @@ import (
)
// check is the Windows-specific implementation of [Check].
//
// Note, that it only checks the owner and the ACEs of the working directory.
// This is due to the assumption that the working directory ACEs are inherited
// by the underlying files and directories, since at least [migrate] sets this
// inheritance mode.
func check(ctx context.Context, l *slog.Logger, workDir, _, _, _, _ string) {
l = l.With("type", typeDir, "path", workDir)
@ -30,6 +35,8 @@ func check(ctx context.Context, l *slog.Logger, workDir, _, _, _, _ string) {
mask windows.ACCESS_MASK,
sid *windows.SID,
) (cont bool) {
l.DebugContext(ctx, "checking access control entry", "mask", mask, "sid", sid)
warn := false
switch {
case hdr.AceType != windows.ACCESS_ALLOWED_ACE_TYPE:

2
internal/permcheck/migrate_unix.go
View File

@ -98,7 +98,7 @@ func chmodPath(ctx context.Context, l *slog.Logger, fpath string, fm fs.FileMode
args = append(args, slogutil.KeyError, err)
default:
lvl = slog.LevelError
msg = "can not change permissions; this can leave your system vulnerable, see " +
msg = "cannot change permissions; this can leave your system vulnerable, see " +
"https://adguard-dns.io/kb/adguard-home/running-securely/#os-service-concerns"
args = append(args, "target_perm", fmt.Sprintf("%#o", fm), slogutil.KeyError, err)
}

67
internal/permcheck/migrate_windows.go
View File

@ -33,6 +33,7 @@ func needsMigration(ctx context.Context, l *slog.Logger, workDir, _ string) (ok
switch {
case hdr.AceType != windows.ACCESS_ALLOWED_ACE_TYPE:
// Skip non-allowed access control entries.
l.DebugContext(ctx, "skipping deny access control entry", "sid", sid)
case !sid.IsWellKnown(windows.WinBuiltinAdministratorsSid):
// Non-administrator access control entries should not have any
// access rights.
@ -55,30 +56,33 @@ func needsMigration(ctx context.Context, l *slog.Logger, workDir, _ string) (ok
}
// migrate is the Windows-specific implementation of [Migrate].
func migrate(ctx context.Context, l *slog.Logger, workDir, _, _, _, _ string) {
dirLogger := l.With("type", typeDir, "path", workDir)
//
// It
func migrate(ctx context.Context, logger *slog.Logger, workDir, _, _, _, _ string) {
l := logger.With("type", typeDir, "path", workDir)
dacl, owner, err := getSecurityInfo(workDir)
if err != nil {
dirLogger.ErrorContext(ctx, "getting security info", slogutil.KeyError, err)
l.ErrorContext(ctx, "getting security info", slogutil.KeyError, err)
return
}
if !owner.IsWellKnown(windows.WinBuiltinAdministratorsSid) {
var admins *windows.SID
admins, err = windows.CreateWellKnownSid(windows.WinBuiltinAdministratorsSid)
if err != nil {
// This log message is not related to the directory.
l.ErrorContext(ctx, "creating administrators sid", slogutil.KeyError, err)
} else {
dirLogger.InfoContext(ctx, "migrating owner", "sid", admins)
owner = admins
}
owner, err = adminsIfNot(owner)
switch {
case err != nil:
l.ErrorContext(ctx, "creating administrators sid", slogutil.KeyError, err)
case owner == nil:
l.DebugContext(ctx, "owner is already an administrator")
default:
l.InfoContext(ctx, "migrating owner", "sid", owner)
}
// TODO(e.burkov): Check for duplicates?
var accessEntries []windows.EXPLICIT_ACCESS
var useACL bool
// Iterate over the access control entries in DACL to determine if its
// migration is needed.
err = rangeACEs(dacl, func(
hdr windows.ACE_HEADER,
mask windows.ACCESS_MASK,
@ -86,27 +90,48 @@ func migrate(ctx context.Context, l *slog.Logger, workDir, _, _, _, _ string) {
) (cont bool) {
switch {
case hdr.AceType != windows.ACCESS_ALLOWED_ACE_TYPE:
// Add non-allowed access control entries as is.
dirLogger.InfoContext(ctx, "migrating deny control entry", "sid", sid)
// Add non-allowed access control entries as is, since they specify
// the access restrictions, which shouldn't be lost.
l.InfoContext(ctx, "migrating deny access control entry", "sid", sid)
accessEntries = append(accessEntries, newDenyExplicitAccess(sid, mask))
useACL = true
case !sid.IsWellKnown(windows.WinBuiltinAdministratorsSid):
// Skip non-administrator ACEs.
dirLogger.InfoContext(ctx, "removing access control entry", "sid", sid)
// Remove non-administrator ACEs, since such accounts should not
// have any access rights.
l.InfoContext(ctx, "removing access control entry", "sid", sid)
useACL = true
default:
dirLogger.InfoContext(ctx, "migrating access control entry", "sid", sid, "mask", mask)
accessEntries = append(accessEntries, newFullExplicitAccess(sid))
// Administrators should have full control. Don't add a new entry
// here since it will be added later in case there are other
// required entries.
l.InfoContext(ctx, "migrating access control entry", "sid", sid, "mask", mask)
useACL = useACL || mask&fullControlMask != fullControlMask
}
return true
})
if err != nil {
dirLogger.ErrorContext(ctx, "filtering access control entries", slogutil.KeyError, err)
l.ErrorContext(ctx, "ranging through access control entries", slogutil.KeyError, err)
return
}
if useACL {
accessEntries = append(accessEntries, newFullExplicitAccess(owner))
}
err = setSecurityInfo(workDir, owner, accessEntries)
if err != nil {
dirLogger.ErrorContext(ctx, "setting security info", slogutil.KeyError, err)
l.ErrorContext(ctx, "setting security info", slogutil.KeyError, err)
}
}
// adminsIfNot returns the administrators SID if sid is not a
// [windows.WinBuiltinAdministratorsSid] yet, or nil if it is.
func adminsIfNot(sid *windows.SID) (admins *windows.SID, err error) {
if sid.IsWellKnown(windows.WinBuiltinAdministratorsSid) {
return nil, nil
}
return windows.CreateWellKnownSid(windows.WinBuiltinAdministratorsSid)
}

36
internal/permcheck/security_windows.go
View File

@ -10,21 +10,21 @@ import (
"golang.org/x/sys/windows"
)
// securityInfo defines the parts of a security descriptor to retrieve and set.
const securityInfo windows.SECURITY_INFORMATION = windows.OWNER_SECURITY_INFORMATION |
// desiredSecInfo defines the parts of a security descriptor to retrieve.
const desiredSecInfo windows.SECURITY_INFORMATION = windows.OWNER_SECURITY_INFORMATION |
windows.DACL_SECURITY_INFORMATION |
windows.PROTECTED_DACL_SECURITY_INFORMATION |
windows.UNPROTECTED_DACL_SECURITY_INFORMATION
// objectType is the type of the object for directories in context of security
// API.
const objectType = windows.SE_FILE_OBJECT
const objectType windows.SE_OBJECT_TYPE = windows.SE_FILE_OBJECT
// fileDeleteChildRight is the mask bit for the right to delete a child object.
// It seems to be missing from the windows package.
// It seems to be missing from the [windows] package.
//
// See https://learn.microsoft.com/en-us/windows-hardware/drivers/ifs/access-mask.
const fileDeleteChildRight = 0b1000000
const fileDeleteChildRight windows.ACCESS_MASK = 0b0100_0000
// fullControlMask is the mask for full control access rights.
const fullControlMask windows.ACCESS_MASK = windows.FILE_LIST_DIRECTORY |
@ -78,12 +78,24 @@ func rangeACEs(dacl *windows.ACL, f aceFunc) (err error) {
}
// setSecurityInfo sets the security information on the specified file, using
// ents to create a discretionary access control list.
// ents to create a discretionary access control list. Both owner and ents can
// be nil, in which case the corresponding information is not set.
func setSecurityInfo(fname string, owner *windows.SID, ents []windows.EXPLICIT_ACCESS) (err error) {
if len(ents) == 0 {
ents = []windows.EXPLICIT_ACCESS{
newFullExplicitAccess(owner),
}
var secInfo windows.SECURITY_INFORMATION
if len(ents) > 0 {
// TODO(e.burkov): Investigate if this whole set is necessary.
secInfo |= windows.DACL_SECURITY_INFORMATION |
windows.PROTECTED_DACL_SECURITY_INFORMATION |
windows.UNPROTECTED_DACL_SECURITY_INFORMATION
}
if owner != nil {
secInfo |= windows.OWNER_SECURITY_INFORMATION
}
if secInfo == 0 {
return errors.Error("no security information to set")
}
acl, err := windows.ACLFromEntries(ents, nil)
@ -91,7 +103,7 @@ func setSecurityInfo(fname string, owner *windows.SID, ents []windows.EXPLICIT_A
return fmt.Errorf("creating access control list: %w", err)
}
err = windows.SetNamedSecurityInfo(fname, objectType, securityInfo, owner, nil, acl, nil)
err = windows.SetNamedSecurityInfo(fname, objectType, desiredSecInfo, owner, nil, acl, nil)
if err != nil {
return fmt.Errorf("setting security info: %w", err)
}
@ -101,7 +113,7 @@ func setSecurityInfo(fname string, owner *windows.SID, ents []windows.EXPLICIT_A
// getSecurityInfo retrieves the security information for the specified file.
func getSecurityInfo(fname string) (dacl *windows.ACL, owner *windows.SID, err error) {
sd, err := windows.GetNamedSecurityInfo(fname, objectType, securityInfo)
sd, err := windows.GetNamedSecurityInfo(fname, objectType, desiredSecInfo)
if err != nil {
return nil, nil, fmt.Errorf("getting security descriptor: %w", err)
}