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Demonstrate that client will improperly accept error packets prior to… 
… TLS handshake

If the MariaDB client is running with `--ssl --ssl-verify-server-cert`, it SHOULD NOT
TRUST any application-level traffic prior to the completion of the TLS handshake,
and the validation of the server's TLS certificate.

1. Build this commit.
2. Start the server, e.g.

       $ DIR=$(mktemp -d); mkdir -p $DIR/data; sql/mariadbd --no-defaults --datadir=$DIR/data --socket=$DIR/mysql.sock --skip-grant-tables --debug
       …
       2023-06-05 15:24:07 0 [Note] sql/mariadbd: ready for connections.
       Version: '10.11.4-MariaDB-debug'  socket: '/tmp/tmp.P4FvcEcKrH/mysql.sock'  port: 3306  Source distribution

3. Attempt to connect to it with `--ssl --ssl-verify-server-cert`:

       $ client/mariadb -h 127.0.0.1
       ERROR 1815 (HY000): Internal error: Client will accept this error as genuine even if running with --ssl --ssl-verify-server-cert, and even though this error is sent in plaintext PRIOR TO TLS HANDSHAKE.

Running `tcpdump` in the background confirms that the client is improperly accepting
the error packet which is sent in plaintext and without a TLS handshake:

    $ sudo tcpdump -n -X -i lo tcp port 3306
    tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
    listening on lo, link-type EN10MB (Ethernet), capture size 262144 bytes
    15:24:46.182853 IP 127.0.0.1.40234 > 127.0.0.1.3306: Flags [S], seq 1546762979, win 65495, options [mss 65495,sackOK,TS val 113496632 ecr 0,nop,wscale 7], length 0
            0x0000:  4500 003c 2b03 4000 8006 d1b6 7f00 0001  E..<+.@.........
            0x0010:  7f00 0001 9d2a 0cea 5c31 bae3 0000 0000  .....*..\1......
            0x0020:  a002 ffd7 fe30 0000 0204 ffd7 0402 080a  .....0..........
            0x0030:  06c3 d238 0000 0000 0103 0307            ...8........
    15:24:46.182917 IP 127.0.0.1.3306 > 127.0.0.1.40234: Flags [S.], seq 3238764927, ack 1546762980, win 65483, options [mss 65495,sackOK,TS val 113496632 ecr 113496632,nop,wscale 7], length 0
            0x0000:  4500 003c 0000 4000 8006 fcb9 7f00 0001  E..<..@.........
            0x0010:  7f00 0001 0cea 9d2a c10b a17f 5c31 bae4  .......*....\1..
            0x0020:  a012 ffcb fe30 0000 0204 ffd7 0402 080a  .....0..........
            0x0030:  06c3 d238 06c3 d238 0103 0307            ...8...8....
    15:24:46.182957 IP 127.0.0.1.40234 > 127.0.0.1.3306: Flags [.], ack 1, win 512, options [nop,nop,TS val 113496632 ecr 113496632], length 0
            0x0000:  4500 0034 2b04 4000 8006 d1bd 7f00 0001  E..4+.@.........
            0x0010:  7f00 0001 9d2a 0cea 5c31 bae4 c10b a180  .....*..\1......
            0x0020:  8010 0200 fe28 0000 0101 080a 06c3 d238  .....(.........8
            0x0030:  06c3 d238                                ...8
    15:24:46.185305 IP 127.0.0.1.3306 > 127.0.0.1.40234: Flags [P.], seq 1:189, ack 1, win 512, options [nop,nop,TS val 113496635 ecr 113496632], length 188
            0x0000:  4508 00f0 622c 4000 8006 99d1 7f00 0001  E...b,@.........
            0x0010:  7f00 0001 0cea 9d2a c10b a180 5c31 bae4  .......*....\1..
            0x0020:  8018 0200 fee4 0000 0101 080a 06c3 d23b  ...............;
            0x0030:  06c3 d238 b800 0000 ff17 0749 6e74 6572  ...8.......Inter
            0x0040:  6e61 6c20 6572 726f 723a 2043 6c69 656e  nal.error:.Clien
            0x0050:  7420 7769 6c6c 2061 6363 6570 7420 7468  t.will.accept.th
            0x0060:  6973 2065 7272 6f72 2061 7320 6765 6e75  is.error.as.genu
            0x0070:  696e 6520 6576 656e 2069 6620 7275 6e6e  ine.even.if.runn
            0x0080:  696e 6720 7769 7468 202d 2d73 736c 202d  ing.with.--ssl.-
            0x0090:  2d73 736c 2d76 6572 6966 792d 7365 7276  -ssl-verify-serv
            0x00a0:  6572 2d63 6572 742c 2061 6e64 2065 7665  er-cert,.and.eve
            0x00b0:  6e20 7468 6f75 6768 2074 6869 7320 6572  n.though.this.er
            0x00c0:  726f 7220 6973 2073 656e 7420 696e 2070  ror.is.sent.in.p
            0x00d0:  6c61 696e 7465 7874 2050 5249 4f52 2054  laintext.PRIOR.T
            0x00e0:  4f20 544c 5320 4841 4e44 5348 414b 452e  O.TLS.HANDSHAKE.
    15:24:46.185343 IP 127.0.0.1.40234 > 127.0.0.1.3306: Flags [.], ack 189, win 511, options [nop,nop,TS val 113496635 ecr 113496635], length 0
            0x0000:  4508 0034 2b05 4000 8006 d1b4 7f00 0001  E..4+.@.........
            0x0010:  7f00 0001 9d2a 0cea 5c31 bae4 c10b a23c  .....*..\1.....<
            0x0020:  8010 01ff fe28 0000 0101 080a 06c3 d23b  .....(.........;
            0x0030:  06c3 d23b                                ...;
    15:24:46.185432 IP 127.0.0.1.40234 > 127.0.0.1.3306: Flags [F.], seq 1, ack 189, win 512, options [nop,nop,TS val 113496635 ecr 113496635], length 0
            0x0000:  4508 0034 2b06 4000 8006 d1b3 7f00 0001  E..4+.@.........
            0x0010:  7f00 0001 9d2a 0cea 5c31 bae4 c10b a23c  .....*..\1.....<
            0x0020:  8011 0200 fe28 0000 0101 080a 06c3 d23b  .....(.........;
            0x0030:  06c3 d23b                                ...;
    15:24:46.185569 IP 127.0.0.1.3306 > 127.0.0.1.40234: Flags [F.], seq 189, ack 2, win 512, options [nop,nop,TS val 113496635 ecr 113496635], length 0
            0x0000:  4508 0034 622d 4000 8006 9a8c 7f00 0001  E..4b-@.........
            0x0010:  7f00 0001 0cea 9d2a c10b a23c 5c31 bae5  .......*...<\1..
            0x0020:  8011 0200 fe28 0000 0101 080a 06c3 d23b  .....(.........;
            0x0030:  06c3 d23b                                ...;
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@dlenski
dlenski committed Jun 5, 2023
1 parent e9fe39d commit ef6c752
Showing 1 changed file with 8 additions and 0 deletions.
8 changes: 8 additions & 0 deletions sql/sql_acl.cc
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Expand Up @@ -14457,6 +14457,14 @@ bool acl_authenticate(THD *thd, uint com_change_user_pkt_len)
DBUG_ASSERT(mpvio.status == MPVIO_EXT::RESTART ||
mpvio.status == MPVIO_EXT::SUCCESS);
}
else if (1)
{
my_error(ER_INTERNAL_ERROR, MYF(0),
"Client will accept this error as genuine even if running with "
"--ssl --ssl-verify-server-cert, and even though this error is "
"sent in plaintext PRIOR TO TLS HANDSHAKE.");
res= CR_ERROR;
}
else
{
/* mark the thd as having no scramble yet */
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