rustsec-2024-0363
Vulnerability from osv_rustsec
Published
2024-08-15 12:00
Modified
2025-10-28 06:02
Summary
Binary Protocol Misinterpretation caused by Truncating or Overflowing Casts
Details

The following presentation at this year's DEF CON was brought to our attention on the SQLx Discord:

SQL Injection isn't Dead: Smuggling Queries at the Protocol Level
http://web.archive.org/web/20240812130923/https://media.defcon.org/DEF%20CON%2032/DEF%20CON%2032%20presentations/DEF%20CON%2032%20-%20Paul%20Gerste%20-%20SQL%20Injection%20Isn't%20Dead%20Smuggling%20Queries%20at%20the%20Protocol%20Level.pdf
(Archive link for posterity.)

Essentially, encoding a value larger than 4GiB can cause the length prefix in the protocol to overflow, causing the server to interpret the rest of the string as binary protocol commands or other data.

It appears SQLx does perform truncating casts in a way that could be problematic, for example: https://github.com/launchbadge/sqlx/blob/6f2905695b9606b5f51b40ce10af63ac9e696bb8/sqlx-postgres/src/arguments.rs#L163

This code has existed essentially since the beginning, so it is reasonable to assume that all published versions <= 0.8.0 are affected.

Mitigation

As always, you should make sure your application is validating untrustworthy user input. Reject any input over 4 GiB, or any input that could encode to a string longer than 4 GiB. Dynamically built queries are also potentially problematic if it pushes the message size over this 4 GiB bound.

Encode::size_hint() can be used for sanity checks, but do not assume that the size returned is accurate. For example, the Json<T> and Text<T> adapters have no reasonable way to predict or estimate the final encoded size, so they just return size_of::<T>() instead.

For web application backends, consider adding some middleware that limits the size of request bodies by default.

Resolution

sqlx 0.8.1 has been released with the fix: https://github.com/launchbadge/sqlx/blob/main/CHANGELOG.md#081---2024-08-23

Postgres users are advised to upgrade ASAP as a possible exploit has been demonstrated: https://github.com/launchbadge/sqlx/issues/3440#issuecomment-2307956901

MySQL and SQLite do not appear to be exploitable, but upgrading is recommended nonetheless.


{
  "affected": [
    {
      "database_specific": {
        "categories": [
          "format-injection"
        ],
        "cvss": null,
        "informational": null
      },
      "ecosystem_specific": {
        "affected_functions": null,
        "affects": {
          "arch": [],
          "functions": [],
          "os": []
        }
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "sqlx",
        "purl": "pkg:cargo/sqlx"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.0.0-0"
            },
            {
              "fixed": "0.8.1"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [
    "GHSA-xmrp-424f-vfpx"
  ],
  "database_specific": {
    "license": "CC0-1.0"
  },
  "details": "The following presentation at this year\u0027s DEF CON was brought to our attention on the SQLx Discord:\n\n\u003e SQL Injection isn\u0027t Dead: Smuggling Queries at the Protocol Level  \n\u003e \u003chttp://web.archive.org/web/20240812130923/https://media.defcon.org/DEF%20CON%2032/DEF%20CON%2032%20presentations/DEF%20CON%2032%20-%20Paul%20Gerste%20-%20SQL%20Injection%20Isn\u0027t%20Dead%20Smuggling%20Queries%20at%20the%20Protocol%20Level.pdf\u003e  \n\u003e (Archive link for posterity.)\n\nEssentially, encoding a value larger than 4GiB can cause the length prefix in the protocol to overflow, \ncausing the server to interpret the rest of the string as binary protocol commands or other data.\n\nIt appears SQLx _does_ perform truncating casts in a way that could be problematic, \nfor example: \u003chttps://github.com/launchbadge/sqlx/blob/6f2905695b9606b5f51b40ce10af63ac9e696bb8/sqlx-postgres/src/arguments.rs#L163\u003e\n\nThis code has existed essentially since the beginning, \nso it is reasonable to assume that all published versions `\u003c= 0.8.0` are affected.\n\n## Mitigation\n\nAs always, you should make sure your application is validating untrustworthy user input. \nReject any input over 4 GiB, or any input that could _encode_ to a string longer than 4 GiB. \nDynamically built queries are also potentially problematic if it pushes the message size over this 4 GiB bound.\n\n[`Encode::size_hint()`](https://docs.rs/sqlx/latest/sqlx/trait.Encode.html#method.size_hint) \ncan be used for sanity checks, but do not assume that the size returned is accurate. \nFor example, the `Json\u003cT\u003e` and `Text\u003cT\u003e` adapters have no reasonable way to predict or estimate the final encoded size, \nso they just return `size_of::\u003cT\u003e()` instead.\n\nFor web application backends, consider adding some middleware that limits the size of request bodies by default.\n\n## Resolution\n\n`sqlx 0.8.1` has been released with the fix: \u003chttps://github.com/launchbadge/sqlx/blob/main/CHANGELOG.md#081---2024-08-23\u003e\n\nPostgres users are advised to upgrade ASAP as a possible exploit has been demonstrated:\n\u003chttps://github.com/launchbadge/sqlx/issues/3440#issuecomment-2307956901\u003e\n\nMySQL and SQLite do not _appear_ to be exploitable, but upgrading is recommended nonetheless.",
  "id": "RUSTSEC-2024-0363",
  "modified": "2025-10-28T06:02:18Z",
  "published": "2024-08-15T12:00:00Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://crates.io/crates/sqlx"
    },
    {
      "type": "ADVISORY",
      "url": "https://rustsec.org/advisories/RUSTSEC-2024-0363.html"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/launchbadge/sqlx/issues/3440"
    }
  ],
  "related": [],
  "severity": [],
  "summary": "Binary Protocol Misinterpretation caused by Truncating or Overflowing Casts"
}


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