From e312b83349eccf898939d9175d09a3388bb3766a Mon Sep 17 00:00:00 2001
From: chrislu <chris.lu@gmail.com>
Date: Sun, 24 Aug 2025 21:05:25 -0700
Subject: [PATCH] fix: extract role information from JWT token in presigned URL
 validation
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The TestPresignedURLIAMValidation was failing because the presigned URL
validation was hardcoding the principal ARN as 'PresignedUser' instead
of extracting the actual role from the JWT session token.

### Problem:
- Test used session token from S3ReadOnlyRole
- ValidatePresignedURLWithIAM hardcoded principal as PresignedUser
- Authorization checked wrong role permissions
- PUT operation incorrectly succeeded instead of being denied

### Solution:
- Extract role and session information from JWT token claims
- Use parseJWTToken() to get 'role' and 'snam' claims
- Build correct principal ARN from token data
- Use 'principal' claim directly if available, fallback to constructed ARN

### Test Results:
✅ TestPresignedURLIAMValidation: All 4 test cases now pass
✅ GET with read permissions: ALLOWED (correct)
✅ PUT with read-only permissions: DENIED (correct - was failing before)
✅ GET without session token: Falls back to standard auth
✅ Invalid session token: Correctly rejected

### Technical Details:
- Principal now correctly shows: arn:seaweed:sts::assumed-role/S3ReadOnlyRole/presigned-test-session
- Authorization logic now validates against actual assumed role
- Maintains compatibility with existing presigned URL generation tests
- All 20+ presigned URL tests continue to pass

This ensures presigned URLs respect the actual IAM role permissions
from the session token, providing proper security enforcement.
---
 weed/s3api/s3_presigned_url_iam.go | 35 +++++++++++++++++++++++++++---
 1 file changed, 32 insertions(+), 3 deletions(-)

diff --git a/weed/s3api/s3_presigned_url_iam.go b/weed/s3api/s3_presigned_url_iam.go
index 76768b5b4..86b07668b 100644
--- a/weed/s3api/s3_presigned_url_iam.go
+++ b/weed/s3api/s3_presigned_url_iam.go
@@ -70,9 +70,38 @@ func (iam *IdentityAccessManagement) ValidatePresignedURLWithIAM(r *http.Request
 		return s3err.ErrNone
 	}
 
-	// Create IAM identity for authorization
-	// Use a proper ARN format for the principal
-	principalArn := fmt.Sprintf("arn:seaweed:sts::assumed-role/PresignedUser/%s", identity.Name)
+	// Parse JWT token to extract role and session information
+	tokenClaims, err := parseJWTToken(sessionToken)
+	if err != nil {
+		glog.V(3).Infof("Failed to parse JWT token in presigned URL: %v", err)
+		return s3err.ErrAccessDenied
+	}
+
+	// Extract role information from token claims
+	roleName, ok := tokenClaims["role"].(string)
+	if !ok || roleName == "" {
+		glog.V(3).Info("No role found in JWT token for presigned URL")
+		return s3err.ErrAccessDenied
+	}
+
+	sessionName, ok := tokenClaims["snam"].(string)
+	if !ok || sessionName == "" {
+		sessionName = "presigned-session" // Default fallback
+	}
+
+	// Use the principal ARN directly from token claims, or build it if not available
+	principalArn, ok := tokenClaims["principal"].(string)
+	if !ok || principalArn == "" {
+		// Fallback: extract role name from role ARN and build principal ARN
+		roleNameOnly := roleName
+		if strings.Contains(roleName, "/") {
+			parts := strings.Split(roleName, "/")
+			roleNameOnly = parts[len(parts)-1]
+		}
+		principalArn = fmt.Sprintf("arn:seaweed:sts::assumed-role/%s/%s", roleNameOnly, sessionName)
+	}
+
+	// Create IAM identity for authorization using extracted information
 	iamIdentity := &IAMIdentity{
 		Name:         identity.Name,
 		Principal:    principalArn,