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shared/ask-password-api: show "(press TAB for no echo)"

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For #8495: it is arguably useful to not show the length of the password
in public spaces. It is possible to press TAB or BS to cancel the asterisks,
but this is not very discoverable. Let's make it discoverable by showing
a message (in gray). The message is "erased" after the first character
is entered.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2020-02-06 09:50:35 +01:00
parent 72c08a471c
commit 8aaf18e08a
2 changed files with 22 additions and 5 deletions
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25
src/shared/ask-password-api.c
View file

@ -394,6 +394,10 @@ finish:
return r;
}
#define NO_ECHO "(no echo) "
#define PRESS_TAB "(press TAB for no echo) "
#define SKIPPED "(skipped)"
int ask_password_tty(
int ttyfd,
const char *message,
@ -409,7 +413,7 @@ int ask_password_tty(
_POLL_MAX,
};
bool reset_tty = false, dirty = false, use_color = false;
bool reset_tty = false, dirty = false, use_color = false, press_tab_visible = false;
_cleanup_close_ int cttyfd = -1, notify = -1;
struct termios old_termios, new_termios;
char passphrase[LINE_MAX + 1] = {}, *x;
@ -465,6 +469,13 @@ int ask_password_tty(
(void) loop_write(ttyfd, message, strlen(message), false);
(void) loop_write(ttyfd, " ", 1, false);
if (!(flags & ASK_PASSWORD_SILENT)) {
if (use_color)
(void) loop_write(ttyfd, ANSI_GREY, STRLEN(ANSI_GREY), false);
(void) loop_write(ttyfd, PRESS_TAB, strlen(PRESS_TAB), false);
press_tab_visible = true;
}
if (use_color)
(void) loop_write(ttyfd, ANSI_NORMAL, STRLEN(ANSI_NORMAL), false);
@ -550,13 +561,19 @@ int ask_password_tty(
}
if (press_tab_visible) {
assert(ttyfd >= 0);
backspace_chars(ttyfd, strlen(PRESS_TAB));
press_tab_visible = false;
}
/* We treat EOF, newline and NUL byte all as valid end markers */
if (n == 0 || c == '\n' || c == 0)
break;
if (c == 4) { /* C-d also known as EOT */
if (ttyfd >= 0)
(void) loop_write(ttyfd, "(skipped)", 9, false);
(void) loop_write(ttyfd, SKIPPED, strlen(SKIPPED), false);
goto skipped;
}
@ -606,7 +623,7 @@ int ask_password_tty(
* first key (and only as first key), or ... */
if (ttyfd >= 0)
(void) loop_write(ttyfd, "(no echo) ", 10, false);
(void) loop_write(ttyfd, NO_ECHO, strlen(NO_ECHO), false);
} else if (ttyfd >= 0)
(void) loop_write(ttyfd, "\a", 1, false);
@ -619,7 +636,7 @@ int ask_password_tty(
/* ... or by pressing TAB at any time. */
if (ttyfd >= 0)
(void) loop_write(ttyfd, "(no echo) ", 10, false);
(void) loop_write(ttyfd, NO_ECHO, strlen(NO_ECHO), false);
} else if (p >= sizeof(passphrase)-1) {

2
src/test/test-ask-password-api.c
View file

@ -8,7 +8,7 @@ static void test_ask_password(void) {
int r;
_cleanup_strv_free_ char **ret = NULL;
r = ask_password_tty(-1, "hello?", "da key", 0, 0, NULL, &ret);
r = ask_password_tty(-1, "hello?", "da key", 0, ASK_PASSWORD_CONSOLE_COLOR, NULL, &ret);
if (r == -ECANCELED)
assert_se(ret == NULL);
else {