diff --git a/solver/llbsolver/provenance/predicate.go b/solver/llbsolver/provenance/predicate.go
index 76132a33c9a8..bf01c0b9d6cc 100644
--- a/solver/llbsolver/provenance/predicate.go
+++ b/solver/llbsolver/provenance/predicate.go
@@ -8,6 +8,7 @@ import (
 	slsa "github.com/in-toto/in-toto-golang/in_toto/slsa_provenance/common"
 	slsa02 "github.com/in-toto/in-toto-golang/in_toto/slsa_provenance/v0.2"
 	provenancetypes "github.com/moby/buildkit/solver/llbsolver/provenance/types"
+	"github.com/moby/buildkit/util/gitutil"
 	"github.com/moby/buildkit/util/purl"
 	"github.com/moby/buildkit/util/urlutil"
 	"github.com/package-url/packageurl-go"
@@ -69,6 +70,35 @@ func digestSetForCommit(commit string) slsa.DigestSet {
 }
 
 func findMaterial(srcs provenancetypes.Sources, uri string) (*slsa.ProvenanceMaterial, bool) {
+	// Git URLs in querystring format or subdir need to be converted to fragment format with only ref
+	gitRef, err := gitutil.ParseURL(uri)
+	if err == nil && gitRef != nil {
+		u := gitRef.Remote
+		var ref string
+		if gitRef.Opts != nil {
+			ref = gitRef.Opts.Ref
+		}
+		if len(gitRef.Query) > 0 {
+			for k, v := range gitRef.Query {
+				if len(v) == 0 {
+					continue
+				}
+				switch k {
+				case "ref":
+					ref = v[0]
+				case "branch":
+					ref = "refs/heads/" + v[0]
+				case "tag":
+					ref = "refs/tags/" + v[0]
+				}
+			}
+		}
+		if ref != "" {
+			u += "#" + ref
+		}
+		uri = u
+	}
+
 	for _, s := range srcs.Git {
 		if s.URL == uri {
 			return &slsa.ProvenanceMaterial{
@@ -102,6 +132,8 @@ func NewPredicate(c *Capture) (*provenancetypes.ProvenancePredicateSLSA02, error
 	contextKey := "context"
 	if v, ok := args["contextkey"]; ok && v != "" {
 		contextKey = v
+	} else if v, ok := c.Args["input:context"]; ok && v != "" {
+		contextKey = "input:context"
 	}
 
 	if v, ok := args[contextKey]; ok && v != "" {