| Bug #92789 | MySQL Net connector 8.0.12 sends illegal connect attributes. | ||
|---|---|---|---|
| Submitted: | 16 Oct 2018 4:54 | Modified: | 23 Nov 2021 18:57 |
| Reporter: | Xiangyu Hu | Email Updates: | |
| Status: | Closed | Impact on me: | |
| Category: | Connector / NET | Severity: | S2 (Serious) |
| Version: | 8.0.12 | OS: | Windows (Windows 7/10) |
| Assigned to: | CPU Architecture: | x86 | |
| Tags: | Connector; | ||
[16 Oct 2018 6:59]
Bradley Grainger
The bug is here: https://github.com/mysql/mysql-connector-net/blob/68c54371821c87ff40a773acc127ce357b46a5ae... Connector/NET computes the length of the C# string (which is in chars, i.e., UTF-16 code units) and then converts the string to UTF-8 for serialization across the wire. The OP's OS name is “Microsoft Windows 7 旗舰版 ”, which is 24 characters (0x18). But this becomes 30 bytes (0x1E) when encoded in UTF-8, so Connector/NET should have written 0x1C for the size of the length-encoded string, not 0x18. Since this version of the connector is out in the wild, Microsoft will need to update their Azure proxy to detect “_client_version” = 8.0.12.0, assume the prefix byte is wrong, and perform UTF-8 decoding on client-supplied connection attributes as they're being deserialized. Or just read the prefix byte at the beginning of this block (i.e., 0x97 in this case) and skip the whole thing.
[16 Oct 2018 18:32]
Bradley Grainger
Typo in previous comment. "But this becomes 30 bytes (0x1E) when encoded in UTF-8, so Connector/NET should have written 0x1C for the size of the length-encoded string, not 0x18." should read "should have written 0x1E"
[18 Oct 2018 4:06]
Xiangyu Hu
Thank you Bradley for your detailed root cause. Since Connector/Net (always) uses UTF-8 across the wire, can a fix be made to make sure the encoded length be set to its UTF-8 size of each attribute? MySQL's definition on Protocol::LengthEncodedString did not rule's its encoding format but the length should be consistant with its real length of bytes.
[22 Oct 2018 12:18]
MySQL Verification Team
Thank you Xiangyu, for the report and Bradley Grainger for the details. regards, Umesh
[23 Nov 2021 18:57]
Christine Cole
Posted by developer: Fixed as of the upcoming MySQL Connector/NET 8.0.28 release, and here's the proposed changelog entry from the documentation team: The calculation used to determine the length of connection attribute values could produce the wrong format in MySQL login packets. Thank you for the bug report.
Description: MySQL Net connector 8.0.12 is sending a wrong format of mysql login packet. It would be failed to be parsed by some frontend MySQL proxies, and impact customer connections. Let's see the Hex and ASCII bytes below and check the "_os_details" attribute. Its value has 0x18 (0n24) bytes long ("Microsoft Windows 7 ......"). The next encoded byte is 0x88 which is obviously out of range. 0000 05 01 00 01 8f a2 1f 00 ff ff ff 00 21 00 00 00 ............!... 0010 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 0020 00 00 00 00 69 74 5f 64 74 79 40 64 61 74 61 2d ....it_dty@data- 0030 63 65 6e 74 65 72 2d 64 62 00 14 26 da b1 90 a4 center-db..&.... 0040 88 1c 39 3f 97 b9 7d 0b 81 94 47 4d 22 62 38 64 ..9?..}...GM"b8d 0050 61 74 61 5f 63 65 6e 74 65 72 00 6d 79 73 71 6c ata_center.mysql 0060 5f 6e 61 74 69 76 65 5f 70 61 73 73 77 6f 72 64 _native_password 0070 00 97 0c 5f 63 6c 69 65 6e 74 5f 6e 61 6d 65 13 ..._client_name. 0080 4d 79 53 71 6c 20 43 6f 6e 6e 65 63 74 6f 72 2f MySql Connector/ 0090 4e 45 54 04 5f 70 69 64 04 35 34 33 36 0f 5f 63 NET._pid.5436._c 00a0 6c 69 65 6e 74 5f 76 65 72 73 69 6f 6e 08 38 2e lient_version.8. 00b0 30 2e 31 32 2e 30 09 5f 70 6c 61 74 66 6f 72 6d 0.12.0._platform 00c0 06 78 38 36 5f 36 34 03 5f 6f 73 05 57 69 6e 36 .x86_64._os.Win6 00d0 34 0b 5f 6f 73 5f 64 65 74 61 69 6c 73 18 4d 69 4._os_details.Mi 00e0 63 72 6f 73 6f 66 74 20 57 69 6e 64 6f 77 73 20 crosoft Windows 00f0 37 20 e6 97 97 e8 88 b0 e7 89 88 20 07 5f 74 68 7 ......... ._th 0100 72 65 61 64 04 36 32 31 36 read.6216 How to repeat: Write a simple client and reference to MySQL Net connector 8.0.12 and connect to a Microsoft Azure MySQL service, the connection string is not correct. Wireshark discloses that the length-encoded format is broken.