ghsa-6845-xw22-ffxv
Vulnerability from github
Summary
There is an error in the stack management when compiling the IR for sha3_64. Concretely, the height variable is miscalculated.
The vulnerability can't be triggered without writing the IR by hand. That is, it cannot be triggered from regular vyper code, it can only be triggered by using the fang binary directly (this binary used to be called vyper-ir prior to v0.3.4).
Details
To compile sha3_64, the arg[0] and arg[1] have to be compiled:
https://github.com/vyperlang/vyper/blob/c150fc49ee9375a930d177044559b83cb95f7963/vyper/ir/compile_ir.py#L585-L586
As can be seen, after compiling the 0th arg, the height variable isn't increased. If new withargs are defined in the inner scope, they are manipulated correctly, because both their height is off and also the global height is off and thus their placement on the stack is computed correctly.
sha3_64 is used for retrieval in mappings. No flow that would cache the key was found, the issue shouldn't be possible to trigger when compiling the compiler-generated IR.
PoC
Suppose the following hand-written IR:
lisp
(with _loc
(with val 1
(with key 2
(sha3_64 val key)))
(seq
(sstore _loc
(with x (sload _loc)
(with ans (add x 1) (seq (assert (ge ans x)) ans))))))
after compilation:
```
the generated bytecode: 6001600281806020525f5260405f2090509050805460018101818110610026579050815550005b5f80fd
0000 60 PUSH1 0x01 0002 60 PUSH1 0x02 0004 81 DUP2 0005 80 DUP1 ***** bad code here!!!!!! 0006 60 PUSH1 0x20 0008 52 MSTORE ```
It can be seen that the second DUP will dup the item on the top of the stack which is incorrect.
Patches
Patched in https://github.com/vyperlang/vyper/pull/4063.
Impact
Versions v0.2.0-v0.3.10 were evaluated, and access of the variable with the invalid height is not reachable from IR generated by the vyper front-end. Because the issue isn't triggered during normal compilation of vyper code, the impact is considered low.
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "vyper"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "0.4.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2024-24559"
],
"database_specific": {
"cwe_ids": [
"CWE-327"
],
"github_reviewed": true,
"github_reviewed_at": "2024-02-05T19:21:52Z",
"nvd_published_at": "2024-02-05T21:15:12Z",
"severity": "LOW"
},
"details": "### Summary\nThere is an error in the stack management when compiling the `IR` for `sha3_64`. Concretely, the `height` variable is miscalculated.\nThe vulnerability can\u0027t be triggered without writing the `IR` by hand. That is, it cannot be triggered from regular vyper code, it can only be triggered by using the `fang` binary directly (this binary used to be called `vyper-ir` prior to v0.3.4).\n\n### Details\nTo compile `sha3_64`, the `arg[0]` and `arg[1]` have to be compiled:\nhttps://github.com/vyperlang/vyper/blob/c150fc49ee9375a930d177044559b83cb95f7963/vyper/ir/compile_ir.py#L585-L586\n\nAs can be seen, after compiling the 0th arg, the `height` variable isn\u0027t increased. If new `withargs` are defined in the inner scope, they are manipulated correctly, because both their `height` is off and also the global `height` is off and thus their placement on the stack is computed correctly.\n\n`sha3_64` is used for retrieval in mappings. No flow that would cache the `key` was found, the issue shouldn\u0027t be possible to trigger when compiling the compiler-generated `IR`.\n\n### PoC\nSuppose the following hand-written IR:\n```lisp\n(with _loc\n\t(with val 1 \n\t\t(with key 2 \n\t\t\t(sha3_64 val key))) \n\t\t\t\t(seq \n\t\t\t\t\t(sstore _loc \n\t\t\t\t\t(with x (sload _loc) \n\t\t\t\t\t\t(with ans (add x 1) (seq (assert (ge ans x)) ans))))))\n```\nafter compilation:\n```\nthe generated bytecode: 6001600281806020525f5260405f2090509050805460018101818110610026579050815550005b5f80fd\n\n0000 60 PUSH1 0x01\n0002 60 PUSH1 0x02\n0004 81 DUP2\n0005 80 DUP1 *********** bad code here!!!!!!\n0006 60 PUSH1 0x20\n0008 52 MSTORE\n```\n\nIt can be seen that the second `DUP` will dup the item on the top of the stack which is incorrect.\n\n### Patches\nPatched in https://github.com/vyperlang/vyper/pull/4063.\n\n### Impact\nVersions v0.2.0-v0.3.10 were evaluated, and access of the variable with the invalid height is not reachable from IR generated by the vyper front-end. Because the issue isn\u0027t triggered during normal compilation of vyper code, the impact is considered low.\n",
"id": "GHSA-6845-xw22-ffxv",
"modified": "2024-06-18T15:14:29Z",
"published": "2024-02-05T19:21:52Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/vyperlang/vyper/security/advisories/GHSA-6845-xw22-ffxv"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-24559"
},
{
"type": "WEB",
"url": "https://github.com/vyperlang/vyper/pull/4063"
},
{
"type": "WEB",
"url": "https://github.com/vyperlang/vyper/commit/d9f9fdadd81a148cbc68f02dbbbcdc0c92fad652"
},
{
"type": "PACKAGE",
"url": "https://github.com/vyperlang/vyper"
},
{
"type": "WEB",
"url": "https://github.com/vyperlang/vyper/blob/c150fc49ee9375a930d177044559b83cb95f7963/vyper/ir/compile_ir.py#L585-L586"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
"type": "CVSS_V3"
}
],
"summary": "Vyper sha3 codegen bug"
}
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.