crypto/tls: don't advertise TLS 1.2-only sigAlgs in TLS 1.3

If a ClientHello only supports TLS 1.3, or if a CertificateRequest is
sent after selecting TLS 1.3, we should not advertise TLS 1.2-only
signature_algorithms like PKCS#1 v1.5 or SHA-1.

However, since crypto/x509 still supports PKCS#1 v1.5, and a direct
CertPool match might not care about the signature in the certificate at
all, start sending a separate signature_algorithms_cert extension to
indicate support for PKCS#1 v1.5 and SHA-1 in certificates.

We were already correctly rejecting these algorithms if the peer
selected them in a TLS 1.3 connection.

Updates #72883

Change-Id: I6a6a4656ab60e1b7fb20fdedc32604dc156953ae
Reviewed-on: https://go-review.googlesource.com/c/go/+/658215
Reviewed-by: Roland Shoemaker <roland@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Auto-Submit: Filippo Valsorda <filippo@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Daniel McCarney <daniel@binaryparadox.net>

1 files changed, 46 insertions, 44 deletions

diff --git a/src/crypto/tls/testdata/Client-TLSv12-ClientCert-RSA-RSAPSS b/src/crypto/tls/testdata/Client-TLSv12-ClientCert-RSA-RSAPSS
index b4c5102535..867ec87afa 100644
--- a/src/crypto/tls/testdata/Client-TLSv12-ClientCert-RSA-RSAPSS
+++ b/src/crypto/tls/testdata/Client-TLSv12-ClientCert-RSA-RSAPSS
@@ -1,5 +1,5 @@
 >>> Flow 1 (client to server)
-00000000  16 03 01 00 fe 01 00 00  fa 03 03 00 00 00 00 00  |................|
+00000000  16 03 01 01 1c 01 00 01  18 03 03 00 00 00 00 00  |................|
 00000010  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
 00000020  00 00 00 00 00 00 00 00  00 00 00 20 00 00 00 00  |........... ....|
 00000030  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00  |................|
@@ -7,21 +7,23 @@
 00000050  cc a8 c0 2b c0 2f c0 2c  c0 30 c0 09 c0 13 c0 0a  |...+./.,.0......|
 00000060  c0 14 00 9c 00 9d 00 2f  00 35 c0 12 00 0a c0 23  |......./.5.....#|
 00000070  c0 27 00 3c c0 07 c0 11  00 05 13 03 13 01 13 02  |.'.<............|
-00000080  01 00 00 7f 00 0b 00 02  01 00 ff 01 00 01 00 00  |................|
+00000080  01 00 00 9d 00 0b 00 02  01 00 ff 01 00 01 00 00  |................|
 00000090  17 00 00 00 12 00 00 00  05 00 05 01 00 00 00 00  |................|
 000000a0  00 0a 00 0a 00 08 00 1d  00 17 00 18 00 19 00 0d  |................|
 000000b0  00 1a 00 18 08 04 04 03  08 07 08 05 08 06 04 01  |................|
-000000c0  05 01 06 01 05 03 06 03  02 01 02 03 00 2b 00 09  |.............+..|
-000000d0  08 03 04 03 03 03 02 03  01 00 33 00 26 00 24 00  |..........3.&.$.|
-000000e0  1d 00 20 2f e5 7d a3 47  cd 62 43 15 28 da ac 5f  |.. /.}.G.bC.(.._|
-000000f0  bb 29 07 30 ff f6 84 af  c4 cf c2 ed 90 99 5f 58  |.).0.........._X|
-00000100  cb 3b 74                                          |.;t|
+000000c0  05 01 06 01 05 03 06 03  02 01 02 03 00 32 00 1a  |.............2..|
+000000d0  00 18 08 04 04 03 08 07  08 05 08 06 04 01 05 01  |................|
+000000e0  06 01 05 03 06 03 02 01  02 03 00 2b 00 09 08 03  |...........+....|
+000000f0  04 03 03 03 02 03 01 00  33 00 26 00 24 00 1d 00  |........3.&.$...|
+00000100  20 2f e5 7d a3 47 cd 62  43 15 28 da ac 5f bb 29  | /.}.G.bC.(.._.)|
+00000110  07 30 ff f6 84 af c4 cf  c2 ed 90 99 5f 58 cb 3b  |.0.........._X.;|
+00000120  74                                                |t|
 >>> Flow 2 (server to client)
-00000000  16 03 03 00 5d 02 00 00  59 03 03 0d 73 c5 43 a1  |....]...Y...s.C.|
-00000010  71 b6 21 da 7a f6 76 44  60 8a 84 ec 6b 1d 70 01  |q.!.z.vD`...k.p.|
-00000020  d8 b2 29 48 db 5d ea da  ea 79 bb 20 3f b9 66 fe  |..)H.]...y. ?.f.|
-00000030  73 db fc 90 18 3f ac e5  1f 5d 86 24 80 75 ec a3  |s....?...].$.u..|
-00000040  c6 aa e9 05 c1 47 21 bd  30 f6 41 43 c0 2f 00 00  |.....G!.0.AC./..|
+00000000  16 03 03 00 5d 02 00 00  59 03 03 97 c2 4c 45 c0  |....]...Y....LE.|
+00000010  22 6a 7d 71 93 1a 71 a7  e1 40 a5 44 5e 39 8a 3e  |"j}q..q..@.D^9.>|
+00000020  99 04 1f e1 74 ad 3a 64  89 ad 93 20 61 76 9a e1  |....t.:d... av..|
+00000030  39 26 af 37 ad ea f2 9c  4c 2e 1b a2 18 0c 73 8e  |9&.7....L.....s.|
+00000040  5b 8b f0 0f 44 04 80 31  5a 49 39 f0 c0 2f 00 00  |[...D..1ZI9../..|
 00000050  11 ff 01 00 01 00 00 0b  00 04 03 00 01 02 00 17  |................|
 00000060  00 00 16 03 03 02 66 0b  00 02 62 00 02 5f 00 02  |......f...b.._..|
 00000070  5c 30 82 02 58 30 82 01  8d a0 03 02 01 02 02 11  |\0..X0..........|
@@ -62,17 +64,17 @@
 000002a0  fa b1 3f 14 11 89 66 79  d1 8e 88 0e 0b a0 9e 30  |..?...fy.......0|
 000002b0  2a c0 67 ef ca 46 02 88  e9 53 81 22 69 22 97 ad  |*.g..F...S."i"..|
 000002c0  80 93 d4 f7 dd 70 14 24  d7 70 0a 46 a1 16 03 03  |.....p.$.p.F....|
-000002d0  00 ac 0c 00 00 a8 03 00  1d 20 03 05 56 dd 40 c0  |......... ..V.@.|
-000002e0  b6 4d 5a df 26 e7 4a f1  a8 47 ef af 12 6e 5f 01  |.MZ.&.J..G...n_.|
-000002f0  2a 7a 19 1a 45 52 8c 47  d2 53 08 04 00 80 8a 6a  |*z..ER.G.S.....j|
-00000300  9d 8b 38 73 da 92 bc f6  05 79 90 af 7a 43 59 62  |..8s.....y..zCYb|
-00000310  bc 97 b6 af ef ce 5f 59  07 81 93 bc c5 3c 5f f9  |......_Y.....<_.|
-00000320  4e 04 45 74 5e cc 7a 6f  82 7a cf 86 0d 68 c9 35  |N.Et^.zo.z...h.5|
-00000330  1d 62 f0 3c ee 77 b5 4c  3a 40 ec 89 fc 97 ff a6  |.b.<.w.L:@......|
-00000340  34 13 8b bc 6b 83 92 e8  52 c5 c6 42 c9 25 ad 37  |4...k...R..B.%.7|
-00000350  41 e7 5a 52 d8 0f 7d fd  a8 9e 86 c6 1b b2 8b 50  |A.ZR..}........P|
-00000360  2a 1c 15 56 00 d8 a8 85  86 05 28 7f a1 3e ba f2  |*..V......(..>..|
-00000370  fe 92 07 c8 a4 4a 2a 5f  d1 53 82 09 9c 65 16 03  |.....J*_.S...e..|
+000002d0  00 ac 0c 00 00 a8 03 00  1d 20 ae c6 bf 84 a5 c3  |......... ......|
+000002e0  05 6b fa 30 b0 ec b7 c2  ff ec 7d e4 b8 e0 f2 0f  |.k.0......}.....|
+000002f0  3d 0e ef de 32 ad f2 6e  52 55 08 04 00 80 07 86  |=...2..nRU......|
+00000300  e1 b2 04 6e b2 43 09 df  c9 20 35 11 3b 0f 10 61  |...n.C... 5.;..a|
+00000310  7e 67 cc 65 c6 60 80 c3  43 7d b8 1c 52 e3 09 af  |~g.e.`..C}..R...|
+00000320  df 38 79 e1 ea 6d b4 6b  bc 50 fe a8 6f 46 6f 9c  |.8y..m.k.P..oFo.|
+00000330  40 1c 6f f2 e5 c6 d9 a4  db 72 24 4a 9c 57 e7 d6  |@.o......r$J.W..|
+00000340  91 91 5b 1b f1 40 f2 d9  58 a2 81 4c d7 be 20 d4  |..[..@..X..L.. .|
+00000350  12 4f 64 05 e5 ec ba 35  22 a7 fe df c9 ea b3 43  |.Od....5"......C|
+00000360  dc 47 29 98 eb c9 92 11  42 a0 80 a4 2a 2e 4d 47  |.G).....B...*.MG|
+00000370  73 9e 0f 13 37 79 92 ca  db c4 84 db 05 4a 16 03  |s...7y.......J..|
 00000380  03 00 0c 0d 00 00 08 01  01 00 02 08 04 00 00 16  |................|
 00000390  03 03 00 04 0e 00 00 00                           |........|
 >>> Flow 3 (client to server)
@@ -118,26 +120,26 @@
 00000270  10 00 00 21 20 2f e5 7d  a3 47 cd 62 43 15 28 da  |...! /.}.G.bC.(.|
 00000280  ac 5f bb 29 07 30 ff f6  84 af c4 cf c2 ed 90 99  |._.).0..........|
 00000290  5f 58 cb 3b 74 16 03 03  00 88 0f 00 00 84 08 04  |_X.;t...........|
-000002a0  00 80 2e 4c af b1 f2 9c  de 14 92 81 c4 7d d1 2f  |...L.........}./|
-000002b0  a3 ba ba df 6f 26 da 2d  86 b4 1f 60 cd fe e7 c1  |....o&.-...`....|
-000002c0  77 02 a5 58 3f 6a fc 1d  ef 93 23 0a 9c c9 70 93  |w..X?j....#...p.|
-000002d0  f8 0c 67 fd 58 83 96 85  62 da 31 e7 a6 78 9f 1c  |..g.X...b.1..x..|
-000002e0  dc 02 b3 b8 bc 05 26 92  e8 6a e7 3c db 5f 80 ee  |......&..j.<._..|
-000002f0  12 75 ff e6 36 36 e6 75  c2 77 d9 63 ef 60 89 db  |.u..66.u.w.c.`..|
-00000300  21 aa 27 85 11 9b 8c eb  be a3 e3 34 0e 01 93 ca  |!.'........4....|
-00000310  a6 65 e3 cd 0f b8 b5 c6  f0 d7 15 69 db 4b 57 d2  |.e.........i.KW.|
-00000320  05 0d 14 03 03 00 01 01  16 03 03 00 28 00 00 00  |............(...|
-00000330  00 00 00 00 00 b5 09 a0  c4 55 89 df 8a 60 83 f3  |.........U...`..|
-00000340  82 12 55 1d d5 50 11 81  74 0f cd b5 ed 9a 00 e7  |..U..P..t.......|
-00000350  58 f7 65 0e 8d                                    |X.e..|
+000002a0  00 80 cb ab 63 1d e6 7e  16 22 27 8b e7 91 f4 5c  |....c..~."'....\|
+000002b0  66 fc 70 eb f7 e6 9c 86  7c 62 30 1c 78 35 bf 09  |f.p.....|b0.x5..|
+000002c0  af d1 5b e3 55 45 98 8d  4c 16 8e 69 cb 8f 45 97  |..[.UE..L..i..E.|
+000002d0  6d c4 6a 25 2a 47 43 64  ac 52 12 bd f5 b9 c0 b0  |m.j%*GCd.R......|
+000002e0  51 38 e7 d4 c8 a2 9c 35  4b 5b ab 21 76 73 68 fe  |Q8.....5K[.!vsh.|
+000002f0  d0 7a f2 95 3c 44 3b 55  b0 89 76 3e 42 e1 23 51  |.z..<D;U..v>B.#Q|
+00000300  29 92 3d 6a df 29 61 ee  52 f5 78 71 97 13 d6 09  |).=j.)a.R.xq....|
+00000310  ff 08 7a 5f 9d 20 49 83  2e 84 82 ba 08 69 db ae  |..z_. I......i..|
+00000320  e2 1b 14 03 03 00 01 01  16 03 03 00 28 00 00 00  |............(...|
+00000330  00 00 00 00 00 6a ff 4b  3d c1 06 20 69 ed f0 a8  |.....j.K=.. i...|
+00000340  7c ec a7 f8 cc 8e a6 de  2d 5e 50 f7 b2 28 9e 97  ||.......-^P..(..|
+00000350  27 35 c3 67 72                                    |'5.gr|
 >>> Flow 4 (server to client)
-00000000  14 03 03 00 01 01 16 03  03 00 28 3f eb 87 50 b0  |..........(?..P.|
-00000010  ae c2 fd 68 30 95 94 61  1c 78 1e 60 3e 38 17 ef  |...h0..a.x.`>8..|
-00000020  ed 9b f1 10 26 5e 53 a3  8c 46 2e 6c 24 b2 ab a7  |....&^S..F.l$...|
-00000030  6c f0 ea                                          |l..|
+00000000  14 03 03 00 01 01 16 03  03 00 28 e3 2f c4 66 7e  |..........(./.f~|
+00000010  8f bf 41 2e 56 f3 d1 76  63 f8 c0 b1 86 50 98 a0  |..A.V..vc....P..|
+00000020  63 c0 c9 23 68 c5 7c f7  08 17 0a 62 78 a8 3d 86  |c..#h.|....bx.=.|
+00000030  5c 1a c6                                          |\..|
 >>> Flow 5 (client to server)
-00000000  17 03 03 00 1e 00 00 00  00 00 00 00 01 fe de 40  |...............@|
-00000010  52 50 79 da 5f 31 52 52  d8 96 04 35 86 92 03 0b  |RPy._1RR...5....|
-00000020  6f 5f 04 15 03 03 00 1a  00 00 00 00 00 00 00 02  |o_..............|
-00000030  9c 85 24 b0 a9 17 24 cf  18 f6 ef f5 0d c6 77 6d  |..$...$.......wm|
-00000040  e0 b2                                             |..|
+00000000  17 03 03 00 1e 00 00 00  00 00 00 00 01 e9 51 91  |..............Q.|
+00000010  f5 cb 2d b9 5e cb b3 52  14 7c e8 18 8f fe b6 ee  |..-.^..R.|......|
+00000020  7a 41 90 15 03 03 00 1a  00 00 00 00 00 00 00 02  |zA..............|
+00000030  d3 5f c1 e2 f5 12 40 c0  4c 1d ab ef 16 3a af 19  |._....@.L....:..|
+00000040  30 59                                             |0Y|