PPC assembly pack: fix copy-paste error in CTR mode

There are two copy-paste errors in handling CTR mode. When dealing
with a 2 or 3 block tail, the code branches to the CBC decryption exit
path, rather than to the CTR exit path.

This can lead to data corruption: in the Linux kernel we have a copy
of this file, and the bug leads to corruption of the IV, which leads
to data corruption when we call the encryption function again later to
encrypt subsequent blocks.

Originally reported to the Linux kernel by Ondrej Mosnáček <omosnacek@gmail.com>

CLA: trivial

Reviewed-by: Tim Hudson <tjh@openssl.org>
Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/8510)

(cherry picked from commit f643deac417a3ccb27f77670bb2b136de49079d9)

diff --git a/crypto/aes/asm/aesp8-ppc.pl b/crypto/aes/asm/aesp8-ppc.pl
index 488b133250c677edd34a98d3fd15ae9c8e5ae6ad..b8dd42dcaaf403bbe4e567a5172a355b249dcd8d 100755 (executable)
--- a/crypto/aes/asm/aesp8-ppc.pl
+++ b/crypto/aes/asm/aesp8-ppc.pl
@@ -1829,7 +1829,7 @@ Lctr32_enc8x_three:
        stvx_u          $out1,$x10,$out
        stvx_u          $out2,$x20,$out
        addi            $out,$out,0x30
-       b               Lcbc_dec8x_done
+       b               Lctr32_enc8x_done
 
 .align 5
 Lctr32_enc8x_two:
@@ -1841,7 +1841,7 @@ Lctr32_enc8x_two:
        stvx_u          $out0,$x00,$out
        stvx_u          $out1,$x10,$out
        addi            $out,$out,0x20
-       b               Lcbc_dec8x_done
+       b               Lctr32_enc8x_done
 
 .align 5
 Lctr32_enc8x_one: