144 lines
5.1 KiB
Diff
144 lines
5.1 KiB
Diff
From 0274a4f3b403162a37a10f199c989f3727ed3ad4 Mon Sep 17 00:00:00 2001
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From: "Todd C. Miller" <Todd.Miller@sudo.ws>
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Date: Thu, 12 Jan 2023 15:55:27 -0700
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Subject: [PATCH] sudoedit: do not permit editor arguments to include "--"
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(CVE-2023-22809) We use "--" to separate the editor and arguments from the
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files to edit. If the editor arguments include "--", sudo can be tricked into
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allowing the user to edit a file not permitted by the security policy. Thanks
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to Matthieu Barjole and Victor Cutillas of Synacktiv (https://synacktiv.com)
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for finding this bug.
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Reference:https://github.com/sudo-project/sudo/commit/0274a4f3b403162a37a10f199c989f3727ed3ad4
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Conflict:NA
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---
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plugins/sudoers/editor.c | 19 ++++++++++++++-----
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plugins/sudoers/sudoers.c | 25 ++++++++++++++++++-------
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plugins/sudoers/visudo.c | 8 ++++++--
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3 files changed, 38 insertions(+), 14 deletions(-)
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diff --git a/plugins/sudoers/editor.c b/plugins/sudoers/editor.c
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index 5ca4eb0af..6d988ff68 100644
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--- a/plugins/sudoers/editor.c
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+++ b/plugins/sudoers/editor.c
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@@ -133,7 +133,7 @@ resolve_editor(const char *ed, size_t edlen, int nfiles, char * const *files,
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const char *tmp, *cp, *ep = NULL;
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const char *edend = ed + edlen;
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struct stat user_editor_sb;
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- int nargc;
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+ int nargc = 0;
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debug_decl(resolve_editor, SUDOERS_DEBUG_UTIL);
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/*
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@@ -151,10 +151,7 @@ resolve_editor(const char *ed, size_t edlen, int nfiles, char * const *files,
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/* If we can't find the editor in the user's PATH, give up. */
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if (find_path(editor, &editor_path, &user_editor_sb, getenv("PATH"), NULL,
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0, allowlist) != FOUND) {
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- sudoers_gc_remove(GC_PTR, editor);
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- free(editor);
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- errno = ENOENT;
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- debug_return_str(NULL);
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+ goto bad;
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}
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/* Count rest of arguments and allocate editor argv. */
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@@ -175,6 +172,17 @@ resolve_editor(const char *ed, size_t edlen, int nfiles, char * const *files,
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nargv[nargc] = copy_arg(cp, ep - cp);
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if (nargv[nargc] == NULL)
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goto oom;
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+
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+ /*
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+ * We use "--" to separate the editor and arguments from the files
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+ * to edit. The editor arguments themselves may not contain "--".
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+ */
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+ if (strcmp(nargv[nargc], "--") == 0) {
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+ sudo_warnx(U_("ignoring editor: %.*s"), (int)edlen, ed);
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+ sudo_warnx("%s", U_("editor arguments may not contain \"--\""));
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+ errno = EINVAL;
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+ goto bad;
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+ }
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}
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if (nfiles != 0) {
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nargv[nargc++] = "--";
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@@ -188,6 +196,7 @@ resolve_editor(const char *ed, size_t edlen, int nfiles, char * const *files,
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debug_return_str(editor_path);
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oom:
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sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
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+bad:
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sudoers_gc_remove(GC_PTR, editor);
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free(editor);
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free(editor_path);
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diff --git a/plugins/sudoers/sudoers.c b/plugins/sudoers/sudoers.c
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index 7b97340ac..1f22853ff 100644
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--- a/plugins/sudoers/sudoers.c
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+++ b/plugins/sudoers/sudoers.c
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@@ -759,21 +759,32 @@ sudoers_policy_main(int argc, char * const argv[], int pwflag, char *env_add[],
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/* Note: must call audit before uid change. */
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if (ISSET(sudo_mode, MODE_EDIT)) {
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+ const char *env_editor = NULL;
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char **edit_argv;
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int edit_argc;
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- const char *env_editor;
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free(safe_cmnd);
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safe_cmnd = find_editor(NewArgc - 1, NewArgv + 1, &edit_argc,
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&edit_argv, NULL, &env_editor, false);
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if (safe_cmnd == NULL) {
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- if (errno != ENOENT)
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+ switch (errno) {
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+ case ENOENT:
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+ audit_failure(NewArgv, N_("%s: command not found"),
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+ env_editor ? env_editor : def_editor);
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+ sudo_warnx(U_("%s: command not found"),
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+ env_editor ? env_editor : def_editor);
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+ goto bad;
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+ case EINVAL:
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+ if (def_env_editor && env_editor != NULL) {
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+ /* User tried to do something funny with the editor. */
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+ log_warningx(SLOG_NO_STDERR|SLOG_AUDIT|SLOG_SEND_MAIL,
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+ "invalid user-specified editor: %s", env_editor);
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+ goto bad;
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+ }
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+ FALLTHROUGH;
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+ default:
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goto done;
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- audit_failure(NewArgv, N_("%s: command not found"),
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- env_editor ? env_editor : def_editor);
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- sudo_warnx(U_("%s: command not found"),
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- env_editor ? env_editor : def_editor);
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- goto bad;
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+ }
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}
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/* find_editor() already g/c'd edit_argv[] */
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sudoers_gc_remove(GC_PTR, NewArgv);
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diff --git a/plugins/sudoers/visudo.c b/plugins/sudoers/visudo.c
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index 82f7f9e56..425071afd 100644
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--- a/plugins/sudoers/visudo.c
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+++ b/plugins/sudoers/visudo.c
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@@ -301,7 +301,7 @@ static char *
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get_editor(int *editor_argc, char ***editor_argv)
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{
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char *editor_path = NULL, **allowlist = NULL;
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- const char *env_editor;
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+ const char *env_editor = NULL;
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static char *files[] = { "+1", "sudoers" };
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unsigned int allowlist_len = 0;
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debug_decl(get_editor, SUDOERS_DEBUG_UTIL);
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@@ -335,7 +335,11 @@ get_editor(int *editor_argc, char ***editor_argv)
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if (editor_path == NULL) {
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if (def_env_editor && env_editor != NULL) {
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/* We are honoring $EDITOR so this is a fatal error. */
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- sudo_fatalx(U_("specified editor (%s) doesn't exist"), env_editor);
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+ if (errno == ENOENT) {
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+ sudo_warnx(U_("specified editor (%s) doesn't exist"),
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+ env_editor);
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+ }
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+ exit(EXIT_FAILURE);
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}
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sudo_fatalx(U_("no editor found (editor path = %s)"), def_editor);
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}
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--
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2.27.0
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