From 719fffa48fc4e6ee0d220111c868cde2dd1609fd Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Sun, 5 Nov 2023 12:09:28 +0100 Subject: [PATCH] trace2: redact passwords from https:// URLs by default It is an unsafe practice to call something like git clone https://user:password@example.com/ This not only risks leaking the password "over the shoulder" or into the readline history of the current Unix shell, it also gets logged via Trace2 if enabled. Let's at least avoid logging such secrets via Trace2, much like we avoid logging secrets in `http.c`. Much like the code in `http.c` is guarded via `GIT_TRACE_REDACT` (defaulting to `true`), we guard the new code via `GIT_TRACE2_REDACT` (also defaulting to `true`). Signed-off-by: Johannes Schindelin --- t/t0210-trace2-normal.sh | 18 ++++++++ trace2.c | 97 +++++++++++++++++++++++++++++++++++++++- 2 files changed, 113 insertions(+), 2 deletions(-) diff --git a/t/t0210-trace2-normal.sh b/t/t0210-trace2-normal.sh index 80e76a4695ed8d..b9adc94aab4165 100755 --- a/t/t0210-trace2-normal.sh +++ b/t/t0210-trace2-normal.sh @@ -283,4 +283,22 @@ test_expect_success 'using global config with include' ' test_cmp expect actual ' +test_expect_success 'unsafe URLs are redacted by default' ' + test_when_finished \ + "rm -r trace.normal unredacted.normal clone clone2" && + + test_config_global \ + "url.$(pwd).insteadOf" https://user:pwd@example.com/ && + test_config_global trace2.configParams "core.*,remote.*.url" && + + GIT_TRACE2="$(pwd)/trace.normal" \ + git clone https://user:pwd@example.com/ clone && + ! grep user:pwd trace.normal && + + GIT_TRACE2_REDACT=0 GIT_TRACE2="$(pwd)/unredacted.normal" \ + git clone https://user:pwd@example.com/ clone2 && + grep "start .* clone https://user:pwd@example.com" unredacted.normal && + grep "remote.origin.url=https://user:pwd@example.com" unredacted.normal +' + test_done diff --git a/trace2.c b/trace2.c index 6dc74dff4c7320..85cbc1a257c380 100644 --- a/trace2.c +++ b/trace2.c @@ -20,6 +20,7 @@ #include "trace2/tr2_tmr.h" static int trace2_enabled; +static int trace2_redact = 1; static int tr2_next_child_id; /* modify under lock */ static int tr2_next_exec_id; /* modify under lock */ @@ -227,6 +228,8 @@ void trace2_initialize_fl(const char *file, int line) if (!tr2_tgt_want_builtins()) return; trace2_enabled = 1; + if (!git_env_bool("GIT_TRACE2_REDACT", 1)) + trace2_redact = 0; tr2_sid_get(); @@ -247,12 +250,92 @@ int trace2_is_enabled(void) return trace2_enabled; } +/* + * Redacts an argument, i.e. ensures that no password in + * https://user:password@host/-style URLs is logged. + * + * Returns the original if nothing needed to be redacted. + * Returns a pointer that needs to be `free()`d otherwise. + */ +static const char *redact_arg(const char *arg) +{ + const char *p, *colon; + size_t at; + + if (!trace2_redact || + (!skip_prefix(arg, "https://", &p) && + !skip_prefix(arg, "http://", &p))) + return arg; + + at = strcspn(p, "@/"); + if (p[at] != '@') + return arg; + + colon = memchr(p, ':', at); + if (!colon) + return arg; + + return xstrfmt("%.*s:%s", (int)(colon - arg), arg, p + at); +} + +/* + * Redacts arguments in an argument list. + * + * Returns the original if nothing needed to be redacted. + * Otherwise, returns a new array that needs to be released + * via `free_redacted_argv()`. + */ +static const char **redact_argv(const char **argv) +{ + int i, j; + const char *redacted = NULL; + const char **ret; + + if (!trace2_redact) + return argv; + + for (i = 0; argv[i]; i++) + if ((redacted = redact_arg(argv[i])) != argv[i]) + break; + + if (!argv[i]) + return argv; + + for (j = 0; argv[j]; j++) + ; /* keep counting */ + + ALLOC_ARRAY(ret, j); + + for (j = 0; j < i; j++) + ret[j] = argv[j]; + ret[i] = redacted; + for (++i; argv[i]; i++) { + redacted = redact_arg(argv[i]); + ret[i] = redacted ? redacted : argv[i]; + } + + return ret; +} + +static void free_redacted_argv(const char **redacted, const char **argv) +{ + int i; + + if (redacted != argv) { + for (i = 0; argv[i]; i++) + if (redacted[i] != argv[i]) + free((void *)redacted[i]); + free((void *)redacted); + } +} + void trace2_cmd_start_fl(const char *file, int line, const char **argv) { struct tr2_tgt *tgt_j; int j; uint64_t us_now; uint64_t us_elapsed_absolute; + const char **redacted; if (!trace2_enabled) return; @@ -260,10 +343,14 @@ void trace2_cmd_start_fl(const char *file, int line, const char **argv) us_now = getnanotime() / 1000; us_elapsed_absolute = tr2tls_absolute_elapsed(us_now); + redacted = redact_argv(argv); + for_each_wanted_builtin (j, tgt_j) if (tgt_j->pfn_start_fl) tgt_j->pfn_start_fl(file, line, us_elapsed_absolute, - argv); + redacted); + + free_redacted_argv(redacted, argv); } void trace2_cmd_exit_fl(const char *file, int line, int code) @@ -637,13 +724,19 @@ void trace2_def_param_fl(const char *file, int line, const char *param, { struct tr2_tgt *tgt_j; int j; + const char *redacted; if (!trace2_enabled) return; + redacted = redact_arg(value); + for_each_wanted_builtin (j, tgt_j) if (tgt_j->pfn_param_fl) - tgt_j->pfn_param_fl(file, line, param, value, kvi); + tgt_j->pfn_param_fl(file, line, param, redacted, kvi); + + if (redacted != value) + free((void *)redacted); } void trace2_def_repo_fl(const char *file, int line, struct repository *repo)