feat(aa): rewrite the toAccess function to parse, convert and verify the access values.

pkg/aa/capability.go

@@ -31,13 +31,11 @@ type Capability struct {
 	Names []string
 }
 
-}
-
 func newCapabilityFromLog(log map[string]string) Rule {
 	return &Capability{
 		RuleBase:  newRuleFromLog(log),
 		Qualifier: newQualifierFromLog(log),
-		Names:     []string{log["capname"]},
+		Names:     Must(toValues(tokCAPABILITY, "name", log["capname"])),
 	}
 }
 

pkg/aa/file.go

@@ -5,6 +5,7 @@
 package aa
 
 import (
+	"fmt"
 	"slices"
 	"strings"
 )
@@ -26,6 +27,23 @@ func init() {
 	}
 }
 
+// cmpFileAccess compares two access strings for file rules.
+// It is aimed to be used in slices.SortFunc.
+func cmpFileAccess(i, j string) int {
+	if slices.Contains(requirements[tokFILE]["access"], i) &&
+		slices.Contains(requirements[tokFILE]["access"], j) {
+		return requirementsWeights[tokFILE]["access"][i] - requirementsWeights[tokFILE]["access"][j]
+	}
+	if slices.Contains(requirements[tokFILE]["transition"], i) &&
+		slices.Contains(requirements[tokFILE]["transition"], j) {
+		return requirementsWeights[tokFILE]["transition"][i] - requirementsWeights[tokFILE]["transition"][j]
+	}
+	if slices.Contains(requirements[tokFILE]["access"], i) {
+		return -1
+	}
+	return 1
+}
+
 type File struct {
 	RuleBase
 	Qualifier
@@ -36,12 +54,19 @@ type File struct {
 }
 
 func newFileFromLog(log map[string]string) Rule {
+	accesses, err := toAccess("file-log", log["requested_mask"])
+	if err != nil {
+		panic(fmt.Errorf("newFileFromLog(%v): %w", log, err))
+	}
+	if slices.Compare(accesses, []string{"l"}) == 0 {
+		return newLinkFromLog(log)
+	}
 	return &File{
 		RuleBase:  newRuleFromLog(log),
 		Qualifier: newQualifierFromLog(log),
 		Owner:     isOwner(log),
 		Path:      log["name"],
-		Access:    toAccess("file-log", log["requested_mask"]),
+		Access:    accesses,
 		Target:    log["target"],
 	}
 }
@@ -104,6 +129,7 @@ func newLinkFromLog(log map[string]string) Rule {
 		Target:    log["target"],
 	}
 }
+
 func (r *Link) Less(other any) bool {
 	o, _ := other.(*Link)
 	if r.Path != o.Path {

pkg/aa/io_uring.go

@@ -25,7 +25,7 @@ func newIOUringFromLog(log map[string]string) Rule {
 	return &IOUring{
 		RuleBase:  newRuleFromLog(log),
 		Qualifier: newQualifierFromLog(log),
-		Access:    toAccess(tokIOURING, log["requested"]),
+		Access:    Must(toAccess(tokIOURING, log["requested"])),
 		Label:     log["label"],
 	}
 }

pkg/aa/mount.go

@@ -6,7 +6,6 @@ package aa
 
 import (
 	"slices"
-	"strings"
 )
 
 const (
@@ -37,7 +36,7 @@ func newMountConditionsFromLog(log map[string]string) MountConditions {
 	if _, present := log["flags"]; present {
 		return MountConditions{
 			FsType:  log["fstype"],
-			Options: strings.Split(log["flags"], ", "),
+			Options: Must(toValues(tokMOUNT, "flags", log["flags"])),
 		}
 	}
 	return MountConditions{FsType: log["fstype"]}

pkg/aa/mqueue.go

@@ -40,7 +40,7 @@ func newMqueueFromLog(log map[string]string) Rule {
 	return &Mqueue{
 		RuleBase:  newRuleFromLog(log),
 		Qualifier: newQualifierFromLog(log),
-		Access:    toAccess(tokMQUEUE, log["requested"]),
+		Access:    Must(toAccess(tokMQUEUE, log["requested"])),
 		Type:      mqueueType,
 		Label:     log["label"],
 		Name:      log["name"],

pkg/aa/ptrace.go

@@ -4,7 +4,9 @@
 
 package aa
 
-import "slices"
+import (
+	"slices"
+)
 
 const tokPTRACE = "ptrace"
 
@@ -27,7 +29,7 @@ func newPtraceFromLog(log map[string]string) Rule {
 	return &Ptrace{
 		RuleBase:  newRuleFromLog(log),
 		Qualifier: newQualifierFromLog(log),
-		Access:    toAccess(tokPTRACE, log["requested_mask"]),
+		Access:    Must(toAccess(tokPTRACE, log["requested_mask"])),
 		Peer:      log["peer"],
 	}
 }

pkg/aa/rules.go

@@ -4,6 +4,12 @@
 
 package aa
 
+import (
+	"fmt"
+	"slices"
+	"strings"
+)
+
 const (
 	tokALLOW = "allow"
 	tokAUDIT = "audit"
@@ -55,3 +61,85 @@ func (r Rules) GetVariables() []*Variable {
 	}
 	return res
 }
+
+// Must is a helper that wraps a call to a function returning (any, error) and
+// panics if the error is non-nil.
+func Must[T any](v T, err error) T {
+	if err != nil {
+		panic(err)
+	}
+	return v
+}
+
+// Helper function to convert a string to a slice of rule values according to
+// the rule requirements as defined in the requirements map.
+func toValues(rule string, key string, input string) ([]string, error) {
+	var sep string
+	req, ok := requirements[rule][key]
+	if !ok {
+		return nil, fmt.Errorf("unrecognized requirement '%s' for rule %s", key, rule)
+	}
+
+	switch {
+	case strings.Contains(input, ","):
+		sep = ","
+	case strings.Contains(input, " "):
+		sep = " "
+	}
+	res := strings.Split(input, sep)
+	for _, access := range res {
+		if !slices.Contains(req, access) {
+			return nil, fmt.Errorf("unrecognized %s: %s", key, access)
+		}
+	}
+	slices.SortFunc(res, func(i, j string) int {
+		return requirementsWeights[rule][key][i] - requirementsWeights[rule][key][j]
+	})
+	return slices.Compact(res), nil
+}
+
+// Helper function to convert an access string to a slice of access according to
+// the rule requirements as defined in the requirements map.
+func toAccess(rule string, input string) ([]string, error) {
+	var res []string
+
+	switch rule {
+	case tokFILE:
+		raw := strings.Split(input, "")
+		trans := []string{}
+		for _, access := range raw {
+			if slices.Contains(requirements[tokFILE]["access"], access) {
+				res = append(res, access)
+			} else {
+				trans = append(trans, access)
+			}
+		}
+
+		transition := strings.Join(trans, "")
+		if len(transition) > 0 {
+			if slices.Contains(requirements[tokFILE]["transition"], transition) {
+				res = append(res, transition)
+			} else {
+				return nil, fmt.Errorf("unrecognized transition: %s", transition)
+			}
+		}
+
+	case tokFILE + "-log":
+		raw := strings.Split(input, "")
+		for _, access := range raw {
+			if slices.Contains(requirements[tokFILE]["access"], access) {
+				res = append(res, access)
+			} else if maskToAccess[access] != "" {
+				res = append(res, maskToAccess[access])
+			} else {
+				return nil, fmt.Errorf("toAccess: unrecognized file access '%s'", input)
+			}
+		}
+
+	default:
+		return toValues(rule, "access", input)
+	}
+
+	slices.SortFunc(res, cmpFileAccess)
+	return slices.Compact(res), nil
+}

pkg/aa/signal.go

@@ -4,7 +4,9 @@
 
 package aa
 
-import "slices"
+import (
+	"slices"
+)
 
 const tokSIGNAL = "signal"
 
@@ -41,8 +43,8 @@ func newSignalFromLog(log map[string]string) Rule {
 	return &Signal{
 		RuleBase:  newRuleFromLog(log),
 		Qualifier: newQualifierFromLog(log),
-		Access:    toAccess(tokSIGNAL, log["requested_mask"]),
+		Access:    Must(toAccess(tokSIGNAL, log["requested_mask"])),
-		Set:       toAccess(tokSIGNAL, log["signal"]),
+		Set:       []string{log["signal"]},
 		Peer:      log["peer"],
 	}
 }

pkg/aa/template.go

@@ -48,6 +48,8 @@ var (
 		"a":  "w",
 		"c":  "w",
 		"d":  "w",
+		"wc": "w",
+		"x":  "ix",
 	}
 
 	// The order the apparmor rules should be sorted
@@ -230,39 +232,3 @@ func getLetterIn(alphabet []string, in string) string {
 	}
 	return ""
 }
-
-// Helper function to convert a access string to slice of access
-func toAccess(constraint string, input string) []string {
-	var res []string
-
-	switch constraint {
-	case "file", "file-log":
-		raw := strings.Split(input, "")
-		trans := []string{}
-		for _, access := range raw {
-			if slices.Contains(fileAccess, access) {
-				res = append(res, access)
-			} else if maskToAccess[access] != "" {
-				res = append(res, maskToAccess[access])
-				trans = append(trans, access)
-			}
-		}
-
-		if constraint != "file-log" {
-			transition := strings.Join(trans, "")
-			if len(transition) > 0 {
-				if slices.Contains(fileExecTransition, transition) {
-					res = append(res, transition)
-				} else {
-					panic("unrecognized pattern: " + transition)
-				}
-			}
-		}
-		return res
-
-	default:
-		res = strings.Fields(input)
-		slices.Sort(res)
-		return slices.Compact(res)
-	}
-}

pkg/aa/unix.go

@@ -36,7 +36,7 @@ func newUnixFromLog(log map[string]string) Rule {
 	return &Unix{
 		RuleBase:  newRuleFromLog(log),
 		Qualifier: newQualifierFromLog(log),
-		Access:    toAccess(tokUNIX, log["requested_mask"]),
+		Access:    Must(toAccess(tokUNIX, log["requested_mask"])),
 		Type:      log["sock_type"],
 		Protocol:  log["protocol"],
 		Address:   log["addr"],