From: Sergey Matveev <stargrave@stargrave.org>
Date: Tue, 15 Feb 2022 08:32:09 +0000 (+0300)
Subject: Fix possible empty buf
X-Git-Tag: v2.0.0~6
X-Git-Url: http://www.git.stargrave.org/?p=paster.git;a=commitdiff_plain;h=2f570cf81328c9b63d4071d1b8ce3cc7e045e9f3

Fix possible empty buf

Read call can return data at bencode-key boundaries, so buf buffer will
be empty and buf[:1] won't work.
---

diff --git a/main.go b/main.go
index 89bcc6e..20ffd34 100644
--- a/main.go
+++ b/main.go
@@ -142,8 +142,7 @@ AnotherKey:
 	if _, err = io.ReadFull(rand.Reader, rnd); err != nil {
 		fatal(err.Error())
 	}
-	fn = "." + base32.StdEncoding.WithPadding(base32.NoPadding).EncodeToString(rnd) +
-		ext
+	fn = "." + base32.StdEncoding.WithPadding(base32.NoPadding).EncodeToString(rnd) + ext
 	fd, err := os.OpenFile(fn, os.O_RDWR|os.O_CREATE|os.O_EXCL, os.FileMode(0666))
 	if err != nil {
 		fatal(err.Error())
@@ -155,10 +154,15 @@ AnotherKey:
 	if _, err = io.CopyN(mw, mr, int64(size-1)); err != nil {
 		goto Failed
 	}
-	if _, err = mr.Read(buf[:1]); err != nil {
+	if len(buf) == 0 {
+		buf = append(buf, 0)
+	} else {
+		buf = buf[:1]
+	}
+	if _, err = mr.Read(buf); err != nil {
 		goto Failed
 	}
-	if _, err = mw.Write(buf[:1]); err != nil {
+	if _, err = mw.Write(buf); err != nil {
 		goto Failed
 	}
 	if (ext == ".txt" || ext == ".url") && buf[0] != '\n' {
@@ -166,7 +170,7 @@ AnotherKey:
 			goto Failed
 		}
 	}
-	if _, err = mr.Read(buf[:1]); err != nil {
+	if _, err = mr.Read(buf); err != nil {
 		goto Failed
 	}
 	if buf[0] != 'e' {