diff options
Diffstat (limited to 'pkg/sentry/usermem/usermem.go')
| -rw-r--r-- | pkg/sentry/usermem/usermem.go | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/pkg/sentry/usermem/usermem.go b/pkg/sentry/usermem/usermem.go index c3c9c153b..99766a803 100644 --- a/pkg/sentry/usermem/usermem.go +++ b/pkg/sentry/usermem/usermem.go @@ -37,6 +37,8 @@ type IO interface { // // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or // any following locks in the lock order. + // + // Postconditions: CopyOut does not retain src. CopyOut(ctx context.Context, addr Addr, src []byte, opts IOOpts) (int, error) // CopyIn copies len(dst) bytes from the memory mapped at addr to dst. @@ -45,6 +47,8 @@ type IO interface { // // Preconditions: The caller must not hold mm.MemoryManager.mappingMu or // any following locks in the lock order. + // + // Postconditions: CopyIn does not retain dst. CopyIn(ctx context.Context, addr Addr, dst []byte, opts IOOpts) (int, error) // ZeroOut sets toZero bytes to 0, starting at addr. It returns the number @@ -237,7 +241,7 @@ func CopyStringIn(ctx context.Context, uio IO, addr Addr, maxlen int, opts IOOpt if !ok { // Last page of kernel memory. The application can't use this // anyway. - return string(buf[:done]), syserror.EFAULT + return stringFromImmutableBytes(buf[:done]), syserror.EFAULT } // Read up to copyStringIncrement bytes at a time. readlen := copyStringIncrement @@ -246,7 +250,7 @@ func CopyStringIn(ctx context.Context, uio IO, addr Addr, maxlen int, opts IOOpt } end, ok := start.AddLength(uint64(readlen)) if !ok { - return string(buf[:done]), syserror.EFAULT + return stringFromImmutableBytes(buf[:done]), syserror.EFAULT } // Shorten the read to avoid crossing page boundaries, since faulting // in a page unnecessarily is expensive. This also ensures that partial @@ -259,15 +263,15 @@ func CopyStringIn(ctx context.Context, uio IO, addr Addr, maxlen int, opts IOOpt // hitting err. for i, c := range buf[done : done+n] { if c == 0 { - return string(buf[:done+i]), nil + return stringFromImmutableBytes(buf[:done+i]), nil } } done += n if err != nil { - return string(buf[:done]), err + return stringFromImmutableBytes(buf[:done]), err } } - return string(buf), syserror.ENAMETOOLONG + return stringFromImmutableBytes(buf), syserror.ENAMETOOLONG } // CopyOutVec copies bytes from src to the memory mapped at ars in uio. The |