This attempts to fix the places where we do the following where
arithmetic_expr may include unvalidated data:
X = grub_malloc(arithmetic_expr);
It accomplishes this by doing the arithmetic ahead of time using grub_add(),
grub_sub(), grub_mul() and testing for overflow before proceeding.
Among other issues, this fixes:
- allocation of integer overflow in grub_video_bitmap_create()
reported by Chris Coulson,
- allocation of integer overflow in grub_png_decode_image_header()
reported by Chris Coulson,
- allocation of integer overflow in grub_squash_read_symlink()
reported by Chris Coulson,
- allocation of integer overflow in grub_ext2_read_symlink()
reported by Chris Coulson,
- allocation of integer overflow in read_section_as_string()
reported by Chris Coulson.
Fixes: CVE-2020-14309, CVE-2020-14310, CVE-2020-14311
Signed-off-by: Peter Jones <pjones@redhat.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
On such a filesystem, inodes may have EXT4_ENCRYPT_FLAG set.
For a regular file, this means its contents are encrypted; for a
directory, this means the filenames in its directory entries are
encrypted; and for a symlink, this means its target is encrypted. Since
GRUB cannot decrypt encrypted contents or filenames, just issue an error
if it would need to do so. This is sufficient to allow unencrypted boot
files to co-exist with encrypted files elsewhere on the filesystem.
(Note that encrypted regular files and symlinks will not normally be
encountered outside an encrypted directory; however, it's possible via
hard links, so they still need to be handled.)
Tested by booting from an ext4 /boot partition on which I had run
'tune2fs -O encrypt'. I also verified that the expected error messages
are printed when trying to access encrypted directories, files, and
symlinks from the GRUB command line. Also ran 'sudo ./grub-fs-tester
ext4_encrypt'; note that this requires e2fsprogs v1.43+ and Linux v4.1+.
Signed-off-by: Eric Biggers <ebiggers@google.com>
strncpy.
* grub-core/fs/jfs.c (grub_jfs_lookup_symlink): Likewise.
* grub-core/kern/misc.c (grub_strncpy): Move from here ...
* include/grub/misc.h (grub_strncpy): ... to here. Make inline.
* grub-core/net/net.c (grub_net_addr_to_str): Use COMPILE_TIME_ASSERT
+ strcpy rather than strncpy.
Peter Jones