*: Fix overflows

3 files changed, 59 insertions, 4 deletions

diff --git a/internal/compress/zlib/reader.go b/internal/compress/zlib/reader.go
index a6497dec..f298a07f 100644
--- a/internal/compress/zlib/reader.go
+++ b/internal/compress/zlib/reader.go
@@ -41,6 +41,7 @@ import (
 	"sync"
 
 	"codeberg.org/lindenii/furgit/internal/compress/flate"
+	"codeberg.org/lindenii/furgit/internal/intconv"
 )
 
 const (
@@ -131,7 +132,14 @@ func (z *Reader) Read(p []byte) (int, error) {
 
 	// Finished file; check checksum.
 	readN, err := io.ReadFull(z.r, z.scratch[0:4])
-	z.trailerRead += uint64(readN)
+	readNUint64, convErr := intconv.IntToUint64(readN)
+	if convErr != nil {
+		z.err = convErr
+
+		return n, z.err
+	}
+
+	z.trailerRead += readNUint64
 
 	if err != nil {
 		if errors.Is(err, io.EOF) {
@@ -160,7 +168,12 @@ func (z *Reader) Read(p []byte) (int, error) {
 func (z *Reader) InputConsumed() uint64 {
 	out := z.headerRead + z.trailerRead
 	if z.progress != nil {
-		out += uint64(z.progress.InputConsumed())
+		progressIn, err := intconv.Int64ToUint64(z.progress.InputConsumed())
+		if err != nil {
+			panic(err)
+		}
+
+		out += progressIn
 	}
 
 	return out
diff --git a/internal/compress/zlib/reader_reset.go b/internal/compress/zlib/reader_reset.go
index 32af0b49..3e78ab5d 100644
--- a/internal/compress/zlib/reader_reset.go
+++ b/internal/compress/zlib/reader_reset.go
@@ -12,6 +12,7 @@ import (
 
 	"codeberg.org/lindenii/furgit/internal/adler32"
 	"codeberg.org/lindenii/furgit/internal/compress/flate"
+	"codeberg.org/lindenii/furgit/internal/intconv"
 )
 
 // reset resets receiver to read a new zlib stream.
@@ -29,7 +30,14 @@ func (z *Reader) reset(r io.Reader, dict []byte) error {
 
 	// Read the header (RFC 1950 section 2.2.).
 	readN, err := io.ReadFull(z.r, z.scratch[0:2])
-	z.headerRead += uint64(readN)
+	readNUint64, convErr := intconv.IntToUint64(readN)
+	if convErr != nil {
+		z.err = convErr
+
+		return z.err
+	}
+
+	z.headerRead += readNUint64
 
 	z.err = err
 	if z.err != nil {
@@ -51,7 +59,14 @@ func (z *Reader) reset(r io.Reader, dict []byte) error {
 	if haveDict {
 		readN, z.err = io.ReadFull(z.r, z.scratch[0:4])
 
-		z.headerRead += uint64(readN)
+		readNUint64, err := intconv.IntToUint64(readN)
+		if err != nil {
+			z.err = err
+
+			return z.err
+		}
+
+		z.headerRead += readNUint64
 		if z.err != nil {
 			if errors.Is(z.err, io.EOF) {
 				z.err = io.ErrUnexpectedEOF
diff --git a/internal/intconv/intconv.go b/internal/intconv/intconv.go
index 67f99a14..c4b429e3 100644
--- a/internal/intconv/intconv.go
+++ b/internal/intconv/intconv.go
@@ -33,6 +33,33 @@ func IntToUint64(v int) (uint64, error) {
 	return uint64(v), nil
 }
 
+// IntToUint32 converts v to uint32, returning an error if it overflows.
+func IntToUint32(v int) (uint32, error) {
+	if v < 0 || v > math.MaxUint32 {
+		return 0, fmt.Errorf("intconv: int %d overflows uint32", v)
+	}
+
+	return uint32(v), nil
+}
+
+// Uint64ToInt64 converts v to int64, returning an error if it overflows.
+func Uint64ToInt64(v uint64) (int64, error) {
+	if v > math.MaxInt64 {
+		return 0, fmt.Errorf("intconv: uint64 %d overflows int64", v)
+	}
+
+	return int64(v), nil
+}
+
+// Int64ToUint64 converts v to uint64, returning an error if v is negative.
+func Int64ToUint64(v int64) (uint64, error) {
+	if v < 0 {
+		return 0, fmt.Errorf("intconv: int64 %d is negative", v)
+	}
+
+	return uint64(v), nil
+}
+
 // Int64ToInt32 converts v to int32, returning an error if it overflows.
 func Int64ToInt32(v int64) (int32, error) {
 	if v < math.MinInt32 || v > math.MaxInt32 {