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_incore.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_incore.h')
| -rw-r--r-- | fs/jfs/jfs_incore.h | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/fs/jfs/jfs_incore.h b/fs/jfs/jfs_incore.h index a466ec41cfbb..721def69e732 100644 --- a/fs/jfs/jfs_incore.h +++ b/fs/jfs/jfs_incore.h @@ -77,11 +77,18 @@ struct jfs_inode_info { unchar _unused[16]; /* 16: */ dxd_t _dxd; /* 16: */ /* _inline may overflow into _inline_ea when needed */ - unchar _inline[128]; /* 128: inline symlink */ /* _inline_ea may overlay the last part of * file._xtroot if maxentry = XTROOTINITSLOT */ - unchar _inline_ea[128]; /* 128: inline extended attr */ + union { + struct { + /* 128: inline symlink */ + unchar _inline[128]; + /* 128: inline extended attr */ + unchar _inline_ea[128]; + }; + unchar _inline_all[256]; + }; } link; } u; #ifdef CONFIG_QUOTA @@ -96,6 +103,7 @@ struct jfs_inode_info { #define i_dtroot u.dir._dtroot #define i_inline u.link._inline #define i_inline_ea u.link._inline_ea +#define i_inline_all u.link._inline_all #define IREAD_LOCK(ip, subclass) \ down_read_nested(&JFS_IP(ip)->rdwrlock, subclass) |