1 files changed, 56 insertions, 0 deletions
diff --git a/debian/patches/CVE-2021-23239.patch b/debian/patches/CVE-2021-23239.patch
new file mode 100644
index 0000000..b54c9f3
--- /dev/null
+++ b/debian/patches/CVE-2021-23239.patch
@@ -0,0 +1,56 @@
+From: Todd C. Miller <Todd.Miller@sudo.ws>
+
+Fix potential directory existing info leak in sudoedit.
+When creating a new file, sudoedit checks to make sure the parent
+directory exists so it can provide the user with a sensible error
+message.  However, this could be used to test for the existence of
+directories not normally accessible to the user by pointing to them
+with a symbolic link when the parent directory is controlled by the
+user.  Problem reported by Matthias Gerstner of SUSE.
+---
+ src/sudo_edit.c | 29 ++++++++++++++++++++++++-----
+ 1 file changed, 24 insertions(+), 5 deletions(-)
+
+diff --git a/src/sudo_edit.c b/src/sudo_edit.c
+index 44b4fb3..888b277 100644
+--- a/src/sudo_edit.c
++++ b/src/sudo_edit.c
+@@ -567,14 +567,33 @@ sudo_edit_create_tfiles(struct command_details *command_details,
+ 	    S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH, command_details);
+ 	if (ofd != -1 || errno == ENOENT) {
+ 	    if (ofd == -1) {
+-		/* New file, verify parent dir exists unless in cwd. */
++		/*
++		 * New file, verify parent dir exists unless in cwd.
++		 * This fails early so the user knows ahead of time if the
++		 * edit won't succeed.  Additional checks are performed
++		 * when copying the temporary file back to the origin.
++		 */
+ 		char *slash = strrchr(files[i], '/');
+ 		if (slash != NULL && slash != files[i]) {
+-		    int serrno = errno;
++		    const int sflags = command_details->flags;
++		    const int serrno = errno;
++		    int dfd;
++
++		    /*
++		     * The parent directory is allowed to be a symbolic
++		     * link as long as *its* parent is not writable.
++		     */
+ 		    *slash = '\0';
+-		    if (stat(files[i], &sb) == 0 && S_ISDIR(sb.st_mode)) {
+-			memset(&sb, 0, sizeof(sb));
+-			rc = 0;
++		    SET(command_details->flags, CD_SUDOEDIT_FOLLOW);
++		    dfd = sudo_edit_open(files[i], DIR_OPEN_FLAGS,
++			S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH, command_details);
++		    command_details->flags = sflags;
++		    if (dfd != -1) {
++			if (fstat(dfd, &sb) == 0 && S_ISDIR(sb.st_mode)) {
++			    memset(&sb, 0, sizeof(sb));
++			    rc = 0;
++			}
++			close(dfd);
+ 		    }
+ 		    *slash = '/';
+ 		    errno = serrno;