hardcoresushi/libgocryptfs
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fusefrontend: catch ReadAt integer overflow

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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
This commit is contained in:
Jakob Unterwurzacher 2021-06-02 18:20:05 +02:00
parent 04858ddd22
commit b23e21f61f
1 changed files with 12 additions and 3 deletions
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15
internal/fusefrontend/file.go
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@ -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 {