Sync with 2.34.4

* maint-2.34:
  Git 2.34.4
  Git 2.33.4
  Git 2.32.3
  Git 2.31.4
  Git 2.30.5
  setup: tighten ownership checks post CVE-2022-24765
  git-compat-util: allow root to access both SUDO_UID and root owned
  t0034: add negative tests and allow git init to mostly work under sudo
  git-compat-util: avoid failing dir ownership checks if running privileged
  t: regression git needs safe.directory when using sudo

1 files changed, 57 insertions, 1 deletions

diff --git a/git-compat-util.h b/git-compat-util.h
index e30a374a84..65f82607cc 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -431,12 +431,68 @@ static inline int git_offset_1st_component(const char *path)
 #endif
 
 #ifndef is_path_owned_by_current_user
+
+#ifdef __TANDEM
+#define ROOT_UID 65535
+#else
+#define ROOT_UID 0
+#endif
+
+/*
+ * Do not use this function when
+ * (1) geteuid() did not say we are running as 'root', or
+ * (2) using this function will compromise the system.
+ *
+ * PORTABILITY WARNING:
+ * This code assumes uid_t is unsigned because that is what sudo does.
+ * If your uid_t type is signed and all your ids are positive then it
+ * should all work fine.
+ * If your version of sudo uses negative values for uid_t or it is
+ * buggy and return an overflowed value in SUDO_UID, then git might
+ * fail to grant access to your repository properly or even mistakenly
+ * grant access to someone else.
+ * In the unlikely scenario this happened to you, and that is how you
+ * got to this message, we would like to know about it; so sent us an
+ * email to git@vger.kernel.org indicating which platform you are
+ * using and which version of sudo, so we can improve this logic and
+ * maybe provide you with a patch that would prevent this issue again
+ * in the future.
+ */
+static inline void extract_id_from_env(const char *env, uid_t *id)
+{
+	const char *real_uid = getenv(env);
+
+	/* discard anything empty to avoid a more complex check below */
+	if (real_uid && *real_uid) {
+		char *endptr = NULL;
+		unsigned long env_id;
+
+		errno = 0;
+		/* silent overflow errors could trigger a bug here */
+		env_id = strtoul(real_uid, &endptr, 10);
+		if (!*endptr && !errno)
+			*id = env_id;
+	}
+}
+
 static inline int is_path_owned_by_current_uid(const char *path)
 {
 	struct stat st;
+	uid_t euid;
+
 	if (lstat(path, &st))
 		return 0;
-	return st.st_uid == geteuid();
+
+	euid = geteuid();
+	if (euid == ROOT_UID)
+	{
+		if (st.st_uid == ROOT_UID)
+			return 1;
+		else
+			extract_id_from_env("SUDO_UID", &euid);
+	}
+
+	return st.st_uid == euid;
 }
 
 #define is_path_owned_by_current_user is_path_owned_by_current_uid