diff options
| author | Kees Cook <keescook@chromium.org> | 2021-06-21 16:23:22 -0700 |
|---|---|---|
| committer | Dave Kleikamp <dave.kleikamp@oracle.com> | 2021-06-23 09:21:52 -0500 |
| commit | 5d299f44d7658f4423e33a0b9915bc8d81687511 (patch) | |
| tree | b8ff7f89dd4370c2a3851c404b7f1a9d09dcb4a7 /fs/jfs/jfs_dinode.h | |
| parent | e15a56b7469529b4225e5c504ba6d51851e3bba4 (diff) | |
jfs: Avoid field-overflowing memcpy()
In preparation for FORTIFY_SOURCE performing compile-time and run-time
field array bounds checking for memcpy(), memmove(), and memset(),
avoid intentionally writing across neighboring fields.
Introduce more unions to cover the full inline data section, so that the
entire 256 bytes can be addressed by memcpy() without thinking it is
crossing field boundaries. Additionally adjusts dir memcpy() to use
existing union names to get the same coverage.
diffoscope shows there are no binary differences before/after excepting
the name of the initcall, which is line number based:
$ diffoscope --exclude-directory-metadata yes before/fs after/fs
--- before/fs
+++ after/fs
│ --- before/fs/jfs
├── +++ after/fs/jfs
│ │ --- before/fs/jfs/super.o
│ ├── +++ after/fs/jfs/super.o
│ │ ├── readelf --wide --symbols {}
│ │ │ @@ -2,15 +2,15 @@
│ │ │ Symbol table '.symtab' contains 158 entries:
│ │ │ Num: Value Size Type Bind Vis Ndx Name
...
│ │ │ - 5: 0000000000000000 0 NOTYPE LOCAL DEFAULT 6 __initcall__kmod_jfs__319_1049_ini
t_jfs_fs6
│ │ │ + 5: 0000000000000000 0 NOTYPE LOCAL DEFAULT 6 __initcall__kmod_jfs__319_1050_ini
t_jfs_fs6
...
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Diffstat (limited to 'fs/jfs/jfs_dinode.h')
| -rw-r--r-- | fs/jfs/jfs_dinode.h | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/fs/jfs/jfs_dinode.h b/fs/jfs/jfs_dinode.h index d6af79e94263..6b231d0d0071 100644 --- a/fs/jfs/jfs_dinode.h +++ b/fs/jfs/jfs_dinode.h @@ -101,7 +101,6 @@ struct dinode { u8 unused[16]; /* 16: */ dxd_t _dxd; /* 16: */ union { - __le32 _rdev; /* 4: */ /* * The fast symlink area * is expected to overflow @@ -109,9 +108,15 @@ struct dinode { * needed (which will clear * INLINEEA). */ - u8 _fastsymlink[128]; - } _u; - u8 _inlineea[128]; + struct { + union { + __le32 _rdev; /* 4: */ + u8 _fastsymlink[128]; + } _u; + u8 _inlineea[128]; + }; + u8 _inline_all[256]; + }; } _special; } _u2; } _file; @@ -122,6 +127,7 @@ struct dinode { #define di_rdev u._file._u2._special._u._rdev #define di_fastsymlink u._file._u2._special._u._fastsymlink #define di_inlineea u._file._u2._special._inlineea +#define di_inline_all u._file._u2._special._inline_all } u; }; |