tree b9a274c81db8d45aeb2c8fed6069a2aabacfb1b5
parent 885a63fb7486a62575d2dc42a73cdefd1c7b0957
author David Benjamin <davidben@google.com> 1547306422 +0000
committer Adam Langley <agl@google.com> 1552599508 +0000

Patch out the aes_nohw fallback in bsaes_cbc_encrypt.

This plugs all bsaes fallback leaks for CBC outside of the key schedule.
The CBC EVP_CIPHERs never call the block function directly when there's
a stream.cbc function available.

This affects CBC decryptions of length < 128 or 16 mod 128.
Performance-wise, we don't really care about CBC apart from passing
glances at its use in TLS. There, the Lucky13 workaround mutes the
effects.

Cortex-A53 (Raspberry Pi 3 Model B+)
Before:
Did 78000 AES-128-CBC-SHA1 (16 bytes) open operations in 3020254us (25825.6 ops/sec): 0.4 MB/s
Did 75000 AES-128-CBC-SHA1 (32 bytes) open operations in 3005760us (24952.1 ops/sec): 0.8 MB/s
Did 71000 AES-128-CBC-SHA1 (64 bytes) open operations in 3038137us (23369.6 ops/sec): 1.5 MB/s
Did 67000 AES-128-CBC-SHA1 (96 bytes) open operations in 3027686us (22129.1 ops/sec): 2.1 MB/s
Did 64000 AES-128-CBC-SHA1 (112 bytes) open operations in 3005491us (21294.4 ops/sec): 2.4 MB/s
Did 59000 AES-128-CBC-SHA1 (128 bytes) open operations in 3020083us (19535.9 ops/sec): 2.5 MB/s
Did 53000 AES-128-CBC-SHA1 (240 bytes) open operations in 3020105us (17549.1 ops/sec): 4.2 MB/s
After:
Did 71668 AES-128-CBC-SHA1 (16 bytes) open operations in 3020896us (23724.1 ops/sec): 0.4 MB/s
Did 71000 AES-128-CBC-SHA1 (32 bytes) open operations in 3040826us (23348.9 ops/sec): 0.7 MB/s
Did 68000 AES-128-CBC-SHA1 (64 bytes) open operations in 3009913us (22592.0 ops/sec): 1.4 MB/s
Did 66000 AES-128-CBC-SHA1 (96 bytes) open operations in 3007597us (21944.4 ops/sec): 2.1 MB/s
Did 59000 AES-128-CBC-SHA1 (112 bytes) open operations in 3002878us (19647.8 ops/sec): 2.2 MB/s
Did 59000 AES-128-CBC-SHA1 (128 bytes) open operations in 3046786us (19364.7 ops/sec): 2.5 MB/s
Did 50000 AES-128-CBC-SHA1 (240 bytes) open operations in 3043643us (16427.7 ops/sec): 3.9 MB/s

Penryn (Mac mini, mid 2010)
Before:
Did 152000 AES-128-CBC-SHA1 (16 bytes) open operations in 1004422us (151330.8 ops/sec): 2.4 MB/s
Did 143000 AES-128-CBC-SHA1 (32 bytes) open operations in 1000443us (142936.7 ops/sec): 4.6 MB/s
Did 136000 AES-128-CBC-SHA1 (48 bytes) open operations in 1006580us (135111.0 ops/sec): 6.5 MB/s
Did 146000 AES-128-CBC-SHA1 (96 bytes) open operations in 1005731us (145168.0 ops/sec): 13.9 MB/s
Did 138000 AES-128-CBC-SHA1 (112 bytes) open operations in 1003330us (137542.0 ops/sec): 15.4 MB/s
Did 133000 AES-128-CBC-SHA1 (128 bytes) open operations in 1005876us (132223.1 ops/sec): 16.9 MB/s
Did 117000 AES-128-CBC-SHA1 (240 bytes) open operations in 1004922us (116426.9 ops/sec): 27.9 MB/s
After:
Did 159000 AES-128-CBC-SHA1 (16 bytes) open operations in 1000505us (158919.7 ops/sec): 2.5 MB/s
Did 157000 AES-128-CBC-SHA1 (32 bytes) open operations in 1006091us (156049.5 ops/sec): 5.0 MB/s
Did 154000 AES-128-CBC-SHA1 (48 bytes) open operations in 1002720us (153582.3 ops/sec): 7.4 MB/s
Did 146000 AES-128-CBC-SHA1 (96 bytes) open operations in 1002567us (145626.2 ops/sec): 14.0 MB/s
Did 135000 AES-128-CBC-SHA1 (112 bytes) open operations in 1001212us (134836.6 ops/sec): 15.1 MB/s
Did 133000 AES-128-CBC-SHA1 (128 bytes) open operations in 1006441us (132148.8 ops/sec): 16.9 MB/s
Did 115000 AES-128-CBC-SHA1 (240 bytes) open operations in 1005246us (114399.9 ops/sec): 27.5 MB/s

Bug: 256
Change-Id: I864b4455ada0d4d245380fce6f869dabb0686354
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/35167
Reviewed-by: Adam Langley <agl@google.com>