From b23e21f61fc51ffa9c1c823778553925e1cc115e Mon Sep 17 00:00:00 2001
From: Jakob Unterwurzacher
Date: Wed, 2 Jun 2021 18:20:05 +0200
Subject: fusefrontend: catch ReadAt integer overflow
Discovered by xfstests generic/564 .
Failure was:
generic/564 - output mismatch (see /opt/fuse-xfstests/results//generic/564.out.bad)
--- tests/generic/564.out 2021-05-08 21:11:05.307395966 +0200
+++ /opt/fuse-xfstests/results//generic/564.out.bad 2021-05-19 19:01:16.912888879 +0200
@@ -31,7 +31,7 @@
source range beyond 8TiB returns 0
destination range beyond 8TiB returns EFBIG
-copy_range: File too large
+copy_range: Function not implemented
---
internal/fusefrontend/file.go | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/internal/fusefrontend/file.go b/internal/fusefrontend/file.go
index 33a3cbe..cbf78e9 100644
--- a/internal/fusefrontend/file.go
+++ b/internal/fusefrontend/file.go
@@ -9,6 +9,7 @@ import (
"fmt"
"io"
"log"
+ "math"
"os"
"sync"
"syscall"
@@ -178,6 +179,10 @@ func (f *File) doRead(dst []byte, off uint64, length uint64) ([]byte, syscall.Er
// Read the backing ciphertext in one go
blocks := f.contentEnc.ExplodePlainRange(off, length)
alignedOffset, alignedLength := blocks[0].JointCiphertextRange(blocks)
+ // f.fd.ReadAt takes an int64!
+ if alignedOffset > math.MaxInt64 {
+ return nil, syscall.EFBIG
+ }
skip := blocks[0].Skip
tlog.Debug.Printf("doRead: off=%d len=%d -> off=%d len=%d skip=%d\n",
off, length, alignedOffset, alignedLength, skip)
@@ -320,9 +325,13 @@ func (f *File) doWrite(data []byte, off int64) (uint32, syscall.Errno) {
// Preallocate so we cannot run out of space in the middle of the write.
// This prevents partially written (=corrupt) blocks.
var err error
- cOff := int64(blocks[0].BlockCipherOff())
+ cOff := blocks[0].BlockCipherOff()
+ // f.fd.WriteAt & syscallcompat.EnospcPrealloc take int64 offsets!
+ if cOff > math.MaxInt64 {
+ return 0, syscall.EFBIG
+ }
if !f.rootNode.args.NoPrealloc {
- err = syscallcompat.EnospcPrealloc(f.intFd(), cOff, int64(len(ciphertext)))
+ err = syscallcompat.EnospcPrealloc(f.intFd(), int64(cOff), int64(len(ciphertext)))
if err != nil {
if !syscallcompat.IsENOSPC(err) {
tlog.Warn.Printf("ino%d fh%d: doWrite: prealloc failed: %v", f.qIno.Ino, f.intFd(), err)
@@ -339,7 +348,7 @@ func (f *File) doWrite(data []byte, off int64) (uint32, syscall.Errno) {
}
}
// Write
- _, err = f.fd.WriteAt(ciphertext, cOff)
+ _, err = f.fd.WriteAt(ciphertext, int64(cOff))
// Return memory to CReqPool
f.rootNode.contentEnc.CReqPool.Put(ciphertext)
if err != nil {
--
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