{ "number": 36536, "repo": "bitcoin/bitcoin", "url": "https://github.com/bitcoin/bitcoin/pull/36536", "title": "log: escape C1 control characters in messages", "author": "fametrano", "author_association": "FIRST_TIME_CONTRIBUTOR", "created_at": "2026-10-15T07:10:08Z", "updated_at": "2026-11-01T18:47:47Z", "description_hash": "c242d6bc5401ba79", "age_days": 17, "draft": false, "labels": [ "Utils/log/libs" ], "milestone": null, "base": "master", "head_sha": "40bb43f158bea7e2efdecff0e17d59d9bf32b924", "head_ref": "logging-escape-c1", "head_repo": "fametrano/bitcoin", "head_history": [ { "t": "2026-10-20T16:46:02Z", "sha": "40bb43f158bea7e2efdecff0e17d59d9bf32b924" } ], "additions": 13, "deletions": 4, "changed_files": 2, "commit_count": 1, "size_bucket": "S", "mergeable_state": "clean", "bot": { "drahtbot": { "present": true, "reviews": { "ack": [ { "login": "jpk68", "url": "https://github.com/bitcoin/bitcoin/pull/36536#issuecomment-6329253274" }, { "login": "Naomi-Gift", "url": "https://github.com/bitcoin/bitcoin/pull/36536#issuecomment-6334301209" }, { "login": "cyb3ralbert", "url": "https://github.com/bitcoin/bitcoin/pull/36536#issuecomment-6336287931" } ] }, "conflicts": [] } }, "acks_parsed": { "jpk68": { "kind": "ack", "hash": "40bb43f158bea7e2efdecff0e17d59d9bf32b924", "t": "2026-10-21T23:57:58Z", "stale": false } }, "acks_tally": { "ack": 1, "stale_ack": 0, "concept_ack": 0, "approach_ack": 0, "nack": 0, "concept_nack": 0, "approach_nack": 0 }, "reviews": { "approved": 0, "changes_requested": 0, "distinct_reviewers": [ "Naomi-Gift", "cyb3ralbert", "jpk68" ] }, "signals": { "needs_rebase": false, "ci_failed": false, "mergeable_state": "clean", "last_author_activity": "2026-11-01T18:47:47Z", "last_reviewer_activity": "2026-10-22T08:26:44Z", "last_reviewer": "cyb3ralbert", "author_silent_days": 0, "waiting_on_author_days": 0, "days_since_update": 0 }, "refs": { "mentioned": [ 17095, 35833 ], "depends_on": [], "fixes": [], "linked_issues": [], "references": [ { "number": 17095, "type": "pull", "state": "closed", "merged": true, "merged_at": "2019-10-16", "title": "util: Filter control characters out of log messages" }, { "number": 35833, "type": "pull", "state": "closed", "merged": true, "merged_at": "2026-09-30", "title": "log: prevent user input from injecting fake log lines" } ], "conflicts": [] }, "stack": { "shares_commits_with": [], "based_on": [], "base_for": [] }, "review_paths": [], "body": "The log escapes control characters so that a message cannot drive the terminal it is printed on, but it lets through the UTF-8 form of the C1 controls U+0080 to U+009F. VTE, the library behind GNOME Terminal and others, decodes these as CSI, OSC, DCS and the rest, like their `ESC [`, `ESC ]` and `ESC P` forms.\n\nI escape the two-byte sequences 0xC2 0x80 to 0xC2 0x9F as `\\xc2\\x9b` and so on. Since 0xC2 is never a continuation byte, this needs no UTF-8 decoder, and all other non-ASCII text still passes untouched, as asked in #17095 and #35833. Single bytes 0x80 to 0x9F stay as they are, since they occur inside valid UTF-8. The new cases in `test_LogEscapeMessage` fail on master and pass with the change.", "commits": [ { "sha": "40bb43f158bea7e2efdecff0e17d59d9bf32b924", "date": "2026-10-20T16:27:56Z", "message": "log: escape C1 control characters in messages\n\nLogEscapeMessage escapes bytes below 0x20 and 0x7f, but passes the\nUTF-8 encodings of U+0080 to U+009F (0xC2 0x80 to 0xC2 0x9F), which\ninclude CSI, OSC and DCS. VTE-based terminals, such as GNOME Terminal,\nact on them.\n\nEscape these two-byte sequences as well. 0xC2 is never a continuation\nbyte, so no decoder state is needed, and every other UTF-8 sequence\nstill passes through unaltered." } ], "timeline": [ { "t": "2026-10-20T16:46:02Z", "kind": "force_push", "who": "fametrano", "commit": "40bb43f158bea7e2efdecff0e17d59d9bf32b924", "id": "push:40bb43f158bea7e2efdecff0e17d59d9bf32b924" }, { "t": "2026-10-21T23:57:58Z", "kind": "comment", "who": "jpk68", "assoc": "CONTRIBUTOR", "text": "ACK 40bb43f158bea7e2efdecff0e17d59d9bf32b924", "id": "c:6329253274", "url": "https://github.com/bitcoin/bitcoin/pull/36536#issuecomment-6329253274", "hash": "fe4586f46a6e7bda", "edited": null }, { "t": "2026-10-22T06:26:51Z", "kind": "comment", "who": "Naomi-Gift", "assoc": "NONE", "text": "tACK 40bb43f158bea7e2efdecff0e17d59d9bf32b924\ntest_LogEscapeMessage passes", "id": "c:6334301209", "url": "https://github.com/bitcoin/bitcoin/pull/36536#issuecomment-6334301209", "hash": "f27cd6592267f71b", "edited": null }, { "t": "2026-10-22T08:26:44Z", "kind": "comment", "who": "cyb3ralbert", "assoc": "CONTRIBUTOR", "text": "tACK 40bb43f158bea7e2efdecff0e17d59d9bf32b924\n\nTested on Linux x86_64 (Ubuntu 24.04), g++ 13.3.0, Release: `logging_tests` pass, also with this branch merged onto current master (de96f3ae). With U+009B and U+009F in a regtest datadir path, debug.log has `\\xc2\\x9b` and `\\xc2\\x9f` on this branch and the raw bytes on the merge-base.\n\nNit: the two new checks don't independently pin down both boundaries. Changing the lower bound to `>= 0x7f` or the end check to `i + 1 <= str.size()` still passes them. The trailing `\\xc2` in the second check is a string literal, so `str[str.size()]` reads the terminating NUL.\n\nAdding after line 141:\n\n```cpp\nBOOST_CHECK_EQUAL(BCLog::LogEscapeMessage(\"\\xc2\\x7f\"), \"\\xc2\" R\"(\\x7f)\");\nBOOST_CHECK_EQUAL(BCLog::LogEscapeMessage(std::string_view{\"\\xc2\\x9b\", 1}), \"\\xc2\");\n```\n\nBoth pass on this branch. Each fails only with its corresponding mutant (lines 142 and 143, respectively; Debian 13 x86_64, GCC 14.2.0, Release).\n\nNit: the `LogEscapeMessage` doc comment and the test comment \"ASCII and UTF-8 must pass through unaltered\" don't mention the C1 exception. Also, U+0100 isn't adjacent to the tested range: that case checks a different lead byte followed by `0x80`. The test itself is fine; only the comment is misleading.", "id": "c:6336287931", "url": "https://github.com/bitcoin/bitcoin/pull/36536#issuecomment-6336287931", "hash": "c13680c8aa86f330", "edited": null }, { "t": "2026-11-01T18:47:47Z", "kind": "comment", "who": "fametrano", "assoc": "NONE", "text": "@cyb3ralbert thanks, both nits are right: the two extra checks pin each boundary, and the comments should mention the C1 exception. I will apply them in a push if a maintainer prefers, and otherwise leave the head as it is, so the three reviews of 40bb43f158 stay valid.", "id": "c:6562301498", "url": "https://github.com/bitcoin/bitcoin/pull/36536#issuecomment-6562301498", "hash": "5058ca1c2278c1a8", "edited": null } ], "labels_log": [ { "t": "2026-10-15T07:10:12Z", "action": "labeled", "label": "Utils/log/libs", "who": "DrahtBot" }, { "t": "2026-10-20T08:25:49Z", "action": "labeled", "label": "Needs rebase", "who": "DrahtBot" }, { "t": "2026-10-20T17:49:40Z", "action": "unlabeled", "label": "Needs rebase", "who": "DrahtBot" } ], "state_log": [], "text_chars": 2841, "text_tokens_estimate": 710, "changed_paths": [ "src/logging.cpp", "src/test/logging_tests.cpp" ], "files": [ { "path": "src/logging.cpp", "add": 7, "del": 4 }, { "path": "src/test/logging_tests.cpp", "add": 6, "del": 0 } ], "test_lines": 6, "git": { "head": "40bb43f158bea7e2efdecff0e17d59d9bf32b924", "head_matches_backup": true, "base": "4303f3b7f0775cdbbe77faddf142e1e44fa590ca", "patch_id": "9c0dc0727e20a5a1", "commits": [ { "sha": "40bb43f158", "subject": "log: escape C1 control characters in messages", "files": 2, "add": 13, "del": 4 } ], "patch_truncated": false }, "patch_id": "9c0dc0727e20a5a1", "input_hash": "f17f05c1bf222879", "extracted_at": "2026-11-02T01:09:49+00:00" }