binfmt_flat: revert "binfmt_flat: don't offset the data start"
authorMax Filippov <jcmvbkbc@gmail.com>
Sat, 8 Aug 2020 18:37:13 +0000 (11:37 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 27 Aug 2020 07:30:50 +0000 (09:30 +0200)
commit6c0496e929d32bb00461cc865495f5db68ab4aca
treef64fb32021401c2cdb249b7d81760bb2ad2b89a5
parent0bb568ce748783deb682a048664312e71fd30644
binfmt_flat: revert "binfmt_flat: don't offset the data start"

commit 2217b982624680d19a80ebb4600d05c8586c4f96 upstream.

binfmt_flat loader uses the gap between text and data to store data
segment pointers for the libraries. Even in the absence of shared
libraries it stores at least one pointer to the executable's own data
segment. Text and data can go back to back in the flat binary image and
without offsetting data segment last few instructions in the text
segment may get corrupted by the data segment pointer.

Fix it by reverting commit a2357223c50a ("binfmt_flat: don't offset the
data start").

Cc: stable@vger.kernel.org
Fixes: a2357223c50a ("binfmt_flat: don't offset the data start")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
fs/binfmt_flat.c