Skip to content

cpp: model BDE bdlbb::Blob byte-buffer taint flow #22455

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
kumarak wants to merge 1 commit into
base: main
Choose a base branch
from
Open

cpp: model BDE bdlbb::Blob byte-buffer taint flow #22455

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 4 additions & 0 deletions cpp/ql/lib/change-notes/2026-08-27-bdlbb-blob-models.md
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,4 @@
---
category: minorAnalysis
---
* Added flow summaries for the BDE `bdlbb::Blob` segmented byte buffer (`BloombergLP::bdlbb`). Taint now flows from a blob to its bytes through the `Blob::buffer`/`BlobBuffer::data` accessor chain and through the `bdlbb::BlobUtil::copy` and `getContiguousRangeOrCopy` helpers, so a blob populated from untrusted input (for example a BlazingMQ message body read via `bmqa::Message::getData`) is tracked into the payload bytes.
19 changes: 19 additions & 0 deletions cpp/ql/lib/ext/bdlbb.model.yml
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,19 @@
# Model of the BDE bdlbb::Blob segmented byte buffer (BloombergLP::bdlbb).
# Lets taint reach a blob's payload bytes, e.g. a message body filled by bmqa::Message::getData.
extensions:
- addsTo:
pack: codeql/cpp-all
extensible: summaryModel
data: # namespace, type, subtypes, name, signature, ext, input, output, kind, provenance
# Accessor chain: a tainted blob taints its buffers, and a tainted buffer taints its bytes.
- ["BloombergLP::bdlbb", "Blob", true, "buffer", "", "", "Argument[-1]", "ReturnValue[*]", "taint", "manual"]
- ["BloombergLP::bdlbb", "BlobBuffer", true, "data", "", "", "Argument[-1]", "ReturnValue[*]", "taint", "manual"]
# BlobUtil read-out: the source blob (Argument[*1]) taints the destination buffer (and the
# returned contiguous range).
- ["BloombergLP::bdlbb", "BlobUtil", true, "copy", "", "", "Argument[*1]", "Argument[*0]", "taint", "manual"]

@jketema jketema Aug 28, 2026

Copy link
Copy Markdown
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Like in the case of the protobuf PR. I think you need to be more specific here, as there seem to be three variants of copy and the input argument can either be argument 1 or argument 2.

- ["BloombergLP::bdlbb", "BlobUtil", true, "getContiguousRangeOrCopy", "", "", "Argument[*1]", "Argument[*0]", "taint", "manual"]
- ["BloombergLP::bdlbb", "BlobUtil", true, "getContiguousRangeOrCopy", "", "", "Argument[*1]", "ReturnValue[*]", "taint", "manual"]
# BlobUtil write-in: the source buffer/blob (Argument[*2]) taints the destination blob.
# (`copy` is overloaded with the source at index 1 or 2; the two rows cover both layouts,
# the extra one only ever reading an int offset/position argument.)
- ["BloombergLP::bdlbb", "BlobUtil", true, "copy", "", "", "Argument[*2]", "Argument[*0]", "taint", "manual"]
69 changes: 69 additions & 0 deletions cpp/ql/test/library-tests/dataflow/external-models/bdlbb.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,69 @@

// --- stub library headers ---

namespace bsl {
typedef unsigned long size_t;
template <class T> class allocator {};
template<class charT> struct char_traits {};
template<class charT, class traits = char_traits<charT>, class Allocator = allocator<charT> >
class basic_string {
public:
basic_string(const charT* s, const Allocator& a = Allocator());
const charT* data() const;
size_t size() const;
};
typedef basic_string<char> string;
}

namespace BloombergLP {
namespace bdlbb {
class BlobBuffer {
public:
char *data() const;
};

class Blob {
public:
const BlobBuffer &buffer(int index) const;
};

struct BlobUtil {
static void copy(char *dstBuffer, const Blob &srcBlob, int position, int length);
static void copy(Blob *dstBlob, int dstOffset, const char *srcBuffer, int length);
static char *getContiguousRangeOrCopy(char *dstBuffer, const Blob &srcBlob, int position,
int length, int alignment);
};
}
}

// --- test code ---

char *source();
void sink(char);

// A blob populated from a tainted buffer taints the bytes read back out of it.
void test_BlobUtil_copy() {
bsl::string s(source());
BloombergLP::bdlbb::Blob blob;
BloombergLP::bdlbb::BlobUtil::copy(&blob, 0, s.data(), s.size());
char dst[16];
BloombergLP::bdlbb::BlobUtil::copy(dst, blob, 0, 16);
sink(*dst); // $ ir
}

void test_accessor_chain() {
bsl::string s(source());
BloombergLP::bdlbb::Blob blob;
BloombergLP::bdlbb::BlobUtil::copy(&blob, 0, s.data(), s.size());
const char *p = blob.buffer(0).data();
sink(*p); // $ ir
}

void test_getContiguousRangeOrCopy() {
bsl::string s(source());
BloombergLP::bdlbb::Blob blob;
BloombergLP::bdlbb::BlobUtil::copy(&blob, 0, s.data(), s.size());
char dst[16];
char *r = BloombergLP::bdlbb::BlobUtil::getContiguousRangeOrCopy(dst, blob, 0, 16, 1);
sink(*r); // $ ir
}
48 changes: 46 additions & 2 deletions cpp/ql/test/library-tests/dataflow/external-models/flow.expected
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -95,7 +95,12 @@ models
| 94 | Summary: Azure::Core::IO; BodyStream; true; ReadToCount; ; ; Argument[-1]; Argument[*0]; taint; manual |
| 95 | Summary: Azure::Core::IO; BodyStream; true; ReadToEnd; ; ; Argument[-1]; ReturnValue.Element; taint; manual |
| 96 | Summary: Azure; Nullable; true; Value; ; ; Argument[-1]; ReturnValue[*]; taint; manual |
| 97 | Summary: boost::asio; ; false; buffer; ; ; Argument[*0]; ReturnValue; taint; manual |
| 97 | Summary: BloombergLP::bdlbb; Blob; true; buffer; ; ; Argument[-1]; ReturnValue[*]; taint; manual |
| 98 | Summary: BloombergLP::bdlbb; BlobBuffer; true; data; ; ; Argument[-1]; ReturnValue[*]; taint; manual |
| 99 | Summary: BloombergLP::bdlbb; BlobUtil; true; copy; ; ; Argument[*1]; Argument[*0]; taint; manual |
| 100 | Summary: BloombergLP::bdlbb; BlobUtil; true; copy; ; ; Argument[*2]; Argument[*0]; taint; manual |
| 101 | Summary: BloombergLP::bdlbb; BlobUtil; true; getContiguousRangeOrCopy; ; ; Argument[*1]; ReturnValue[*]; taint; manual |
| 102 | Summary: boost::asio; ; false; buffer; ; ; Argument[*0]; ReturnValue; taint; manual |
edges
| asio_streams.cpp:87:34:87:44 | read_until output argument | asio_streams.cpp:91:7:91:17 | recv_buffer | provenance | Src:MaD:56 |
| asio_streams.cpp:87:34:87:44 | read_until output argument | asio_streams.cpp:93:29:93:39 | recv_buffer | provenance | Src:MaD:56 Sink:MaD:4 |
Expand All @@ -104,7 +109,7 @@ edges
| asio_streams.cpp:100:44:100:62 | call to buffer | asio_streams.cpp:100:44:100:62 | call to buffer | provenance | |
| asio_streams.cpp:100:44:100:62 | call to buffer | asio_streams.cpp:101:7:101:17 | send_buffer | provenance | |
| asio_streams.cpp:100:44:100:62 | call to buffer | asio_streams.cpp:103:29:103:39 | send_buffer | provenance | Sink:MaD:4 |
| asio_streams.cpp:100:64:100:71 | *send_str | asio_streams.cpp:100:44:100:62 | call to buffer | provenance | MaD:97 |
| asio_streams.cpp:100:64:100:71 | *send_str | asio_streams.cpp:100:44:100:62 | call to buffer | provenance | MaD:102 |
| azure.cpp:253:48:253:60 | *call to GetBodyStream | azure.cpp:257:5:257:8 | *resp | provenance | |
| azure.cpp:253:48:253:60 | *call to GetBodyStream | azure.cpp:262:5:262:8 | *resp | provenance | |
| azure.cpp:253:48:253:60 | *call to GetBodyStream | azure.cpp:266:38:266:41 | *resp | provenance | |
Expand Down Expand Up @@ -144,6 +149,24 @@ edges
| azure.cpp:294:38:294:53 | call to operator[] | azure.cpp:295:10:295:20 | contentType | provenance | |
| azure.cpp:294:38:294:53 | call to operator[] | azure.cpp:295:10:295:20 | contentType | provenance | |
| azure.cpp:295:10:295:20 | contentType | azure.cpp:295:10:295:20 | contentType | provenance | |
| bdlbb.cpp:46:16:46:23 | call to source | bdlbb.cpp:48:49:48:52 | *call to data | provenance | TaintFunction |
| bdlbb.cpp:48:37:48:41 | copy output argument | bdlbb.cpp:50:42:50:45 | *blob | provenance | |
| bdlbb.cpp:48:49:48:52 | *call to data | bdlbb.cpp:48:37:48:41 | copy output argument | provenance | MaD:100 |
| bdlbb.cpp:50:37:50:39 | copy output argument | bdlbb.cpp:51:7:51:10 | * ... | provenance | |
| bdlbb.cpp:50:42:50:45 | *blob | bdlbb.cpp:50:37:50:39 | copy output argument | provenance | MaD:99 |
| bdlbb.cpp:55:16:55:23 | call to source | bdlbb.cpp:57:49:57:52 | *call to data | provenance | TaintFunction |
| bdlbb.cpp:57:37:57:41 | copy output argument | bdlbb.cpp:58:18:58:21 | *blob | provenance | |
| bdlbb.cpp:57:49:57:52 | *call to data | bdlbb.cpp:57:37:57:41 | copy output argument | provenance | MaD:100 |
| bdlbb.cpp:58:18:58:21 | *blob | bdlbb.cpp:58:29:58:32 | *call to buffer | provenance | MaD:97 |
| bdlbb.cpp:58:18:58:38 | *call to data | bdlbb.cpp:58:18:58:38 | *call to data | provenance | |
| bdlbb.cpp:58:18:58:38 | *call to data | bdlbb.cpp:59:7:59:8 | * ... | provenance | |
| bdlbb.cpp:58:29:58:32 | *call to buffer | bdlbb.cpp:58:18:58:38 | *call to data | provenance | MaD:98 |
| bdlbb.cpp:63:16:63:23 | call to source | bdlbb.cpp:65:49:65:52 | *call to data | provenance | TaintFunction |
| bdlbb.cpp:65:37:65:41 | copy output argument | bdlbb.cpp:67:72:67:75 | *blob | provenance | |
| bdlbb.cpp:65:49:65:52 | *call to data | bdlbb.cpp:65:37:65:41 | copy output argument | provenance | MaD:100 |
| bdlbb.cpp:67:12:67:65 | *call to getContiguousRangeOrCopy | bdlbb.cpp:67:12:67:65 | *call to getContiguousRangeOrCopy | provenance | |
| bdlbb.cpp:67:12:67:65 | *call to getContiguousRangeOrCopy | bdlbb.cpp:68:7:68:8 | * ... | provenance | |
| bdlbb.cpp:67:72:67:75 | *blob | bdlbb.cpp:67:12:67:65 | *call to getContiguousRangeOrCopy | provenance | MaD:101 |
| test.cpp:7:47:7:52 | value2 | test.cpp:7:64:7:69 | value2 | provenance | |
| test.cpp:7:64:7:69 | value2 | test.cpp:7:5:7:30 | *ymlStepGenerated_with_body | provenance | |
| test.cpp:10:10:10:18 | call to ymlSource | test.cpp:10:10:10:18 | call to ymlSource | provenance | Src:MaD:48 |
Expand Down Expand Up @@ -532,6 +555,27 @@ nodes
| azure.cpp:295:10:295:20 | contentType | semmle.label | contentType |
| azure.cpp:295:10:295:20 | contentType | semmle.label | contentType |
| azure.cpp:295:10:295:20 | contentType | semmle.label | contentType |
| bdlbb.cpp:46:16:46:23 | call to source | semmle.label | call to source |
| bdlbb.cpp:48:37:48:41 | copy output argument | semmle.label | copy output argument |
| bdlbb.cpp:48:49:48:52 | *call to data | semmle.label | *call to data |
| bdlbb.cpp:50:37:50:39 | copy output argument | semmle.label | copy output argument |
| bdlbb.cpp:50:42:50:45 | *blob | semmle.label | *blob |
| bdlbb.cpp:51:7:51:10 | * ... | semmle.label | * ... |
| bdlbb.cpp:55:16:55:23 | call to source | semmle.label | call to source |
| bdlbb.cpp:57:37:57:41 | copy output argument | semmle.label | copy output argument |
| bdlbb.cpp:57:49:57:52 | *call to data | semmle.label | *call to data |
| bdlbb.cpp:58:18:58:21 | *blob | semmle.label | *blob |
| bdlbb.cpp:58:18:58:38 | *call to data | semmle.label | *call to data |
| bdlbb.cpp:58:18:58:38 | *call to data | semmle.label | *call to data |
| bdlbb.cpp:58:29:58:32 | *call to buffer | semmle.label | *call to buffer |
| bdlbb.cpp:59:7:59:8 | * ... | semmle.label | * ... |
| bdlbb.cpp:63:16:63:23 | call to source | semmle.label | call to source |
| bdlbb.cpp:65:37:65:41 | copy output argument | semmle.label | copy output argument |
| bdlbb.cpp:65:49:65:52 | *call to data | semmle.label | *call to data |
| bdlbb.cpp:67:12:67:65 | *call to getContiguousRangeOrCopy | semmle.label | *call to getContiguousRangeOrCopy |
| bdlbb.cpp:67:12:67:65 | *call to getContiguousRangeOrCopy | semmle.label | *call to getContiguousRangeOrCopy |
| bdlbb.cpp:67:72:67:75 | *blob | semmle.label | *blob |
| bdlbb.cpp:68:7:68:8 | * ... | semmle.label | * ... |
| test.cpp:7:5:7:30 | *ymlStepGenerated_with_body | semmle.label | *ymlStepGenerated_with_body |
| test.cpp:7:47:7:52 | value2 | semmle.label | value2 |
| test.cpp:7:64:7:69 | value2 | semmle.label | value2 |
Expand Down
8 changes: 8 additions & 0 deletions cpp/ql/test/library-tests/dataflow/external-models/steps.expected
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,14 @@
| azure.cpp:262:5:262:8 | *resp | azure.cpp:262:23:262:28 | ReadToCount output argument |
| azure.cpp:287:79:287:98 | call to string | azure.cpp:287:62:287:99 | call to Url |
| azure.cpp:289:24:289:56 | call to GetHeader | azure.cpp:289:63:289:65 | call to Value |
| bdlbb.cpp:48:49:48:52 | *call to data | bdlbb.cpp:48:37:48:41 | copy output argument |
| bdlbb.cpp:50:42:50:45 | *blob | bdlbb.cpp:50:37:50:39 | copy output argument |
| bdlbb.cpp:57:49:57:52 | *call to data | bdlbb.cpp:57:37:57:41 | copy output argument |
| bdlbb.cpp:58:18:58:21 | *blob | bdlbb.cpp:58:29:58:32 | *call to buffer |
| bdlbb.cpp:58:29:58:32 | *call to buffer | bdlbb.cpp:58:18:58:38 | *call to data |
| bdlbb.cpp:65:49:65:52 | *call to data | bdlbb.cpp:65:37:65:41 | copy output argument |
| bdlbb.cpp:67:72:67:75 | *blob | bdlbb.cpp:67:12:67:65 | *call to getContiguousRangeOrCopy |
| bdlbb.cpp:67:72:67:75 | *blob | bdlbb.cpp:67:67:67:69 | getContiguousRangeOrCopy output argument |
| test.cpp:17:24:17:24 | x | test.cpp:17:10:17:22 | call to ymlStepManual |
| test.cpp:21:27:21:27 | x | test.cpp:21:10:21:25 | call to ymlStepGenerated |
| test.cpp:25:35:25:35 | x | test.cpp:25:11:25:33 | call to ymlStepManual_with_body |
Expand Down