diff options
| author | Michael Pratt <mpratt@google.com> | 2019-10-01 11:29:35 -0700 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2019-10-01 11:30:36 -0700 |
| commit | 53cc72da90f5b5a76b024b47fe4e38a81b495eb4 (patch) | |
| tree | f6e771a4d5d91e8e4e9b40bf85698797eb767a7c /pkg/sentry | |
| parent | 7a234f736fe0e91824b50631e408bd07b2c0ed31 (diff) | |
Honor X bit on extra anon pages in PT_LOAD segments
Linux changed this behavior in 16e72e9b30986ee15f17fbb68189ca842c32af58
(v4.11). Previously, extra pages were always mapped RW. Now, those pages will
be executable if the segment specified PF_X. They still must be writeable.
PiperOrigin-RevId: 272256280
Diffstat (limited to 'pkg/sentry')
| -rw-r--r-- | pkg/sentry/loader/elf.go | 18 |
1 files changed, 11 insertions, 7 deletions
diff --git a/pkg/sentry/loader/elf.go b/pkg/sentry/loader/elf.go index ba9c9ce12..2d9251e92 100644 --- a/pkg/sentry/loader/elf.go +++ b/pkg/sentry/loader/elf.go @@ -323,18 +323,22 @@ func mapSegment(ctx context.Context, m *mm.MemoryManager, f *fs.File, phdr *elf. return syserror.ENOEXEC } + // N.B. Linux uses vm_brk_flags to map these pages, which only + // honors the X bit, always mapping at least RW. ignoring These + // pages are not included in the final brk region. + prot := usermem.ReadWrite + if phdr.Flags&elf.PF_X == elf.PF_X { + prot.Execute = true + } + if _, err := m.MMap(ctx, memmap.MMapOpts{ Length: uint64(anonSize), Addr: anonAddr, // Fixed without Unmap will fail the mmap if something is // already at addr. - Fixed: true, - Private: true, - // N.B. Linux uses vm_brk to map these pages, ignoring - // the segment protections, instead always mapping RW. - // These pages are not included in the final brk - // region. - Perms: usermem.ReadWrite, + Fixed: true, + Private: true, + Perms: prot, MaxPerms: usermem.AnyAccess, }); err != nil { ctx.Infof("Error mapping PT_LOAD segment %v anonymous memory: %v", phdr, err) |