Hello,

when compiling aespipe from sources (https://loop-aes.sourceforge.net/aespipe/), GCC produces a wrong binary that generates the wrong cipher text when encrypting known text. This happens with these two compilation flags used TOGETHER:

CFLAGS="-O2 -flto=auto"

Interstingly, i686 and x86_64 arches are NOT AFFECTED. Only these arches are known to be affected:

• armv7hl
• aarch64
• ppc64le
• s390x

The problem was first spotted when compiling aespipe package for Fedora-34:
https://koji.fedoraproject.org/koji/taskinfo?taskID=62266480

On Fedora-33, the package has compiled without problems.

gcc v10 is known as the last working version
gcc v11 is known as the first broken version

The issue persists when compiling aespipe for Fedora rawhide with GCC v13.

WORKAROUND is to use
CFLAGS="-O1 -flto=auto"
or
CFLAGS="-O0 -flto=auto"

or omit -flto=auto:
CFLAGS="-O2"

I have reproduced the issue on RHEL-9:

• On RHEL-8, with GCC 8.5.0, aespipe compiles correctly with CFLAGS="-O2 -flto=auto"
• On RHEL-9, with GCC 11.4.1, aespipe compiles wrongly with CFLAGS="-O2 -flto=auto"

Reproducer:

wget https://loop-aes.sourceforge.net/aespipe/aespipe-v2.4f.tar.bz2
tar xvf aespipe-v2.4f.tar.bz2
cd aespipe-v2.4f
make clean; ./configure CFLAGS="-O2 -flto=auto"; make; make tests

When binary is correct (expected output):

*** Test results ok ***

aespipe was compiled correctly and has generated the desired output when encrypting and decrypting messages.

When the binary is wrong (reproducing the issue):

make[1]: Entering directory '/root/A/aespipe-v2.4f'
./aespipe -v -p 3 -e AES128 -K ./gpgkey2.asc -G test-dir1 <test-file3 >test-file1 3<test-file4
./aespipe: C-language AES, 128 key bits, encrypting, multi-key-v2 mode, RAM not locked
make test-part3
make[2]: Entering directory '/root/A/aespipe-v2.4f'
md5sum test-file1 >test-file2
echo "f9825b79873f5c439ae9371c1a929a6c  test-file1" >test-file5
make[2]: Leaving directory '/root/A/aespipe-v2.4f'
cmp test-file2 test-file5
test-file2 test-file5 differ: byte 1, line 1
make[1]: *** [Makefile:120: test-part2] Error 1
make[1]: Leaving directory '/root/A/aespipe-v2.4f'
make: *** [Makefile:87: tests] Error 2

It means that aespipe has NOT generated the expected output. The message was encrypted wrongly.