upstream: fix setting of $SSH_ASKPASS_PROMPT - it shouldn't be set

when asking passphrases, only when confirming the use of a key (i.e. for
ssh-agent keys added with "ssh-add -c keyfile")

OpenBSD-Commit-ID: 6643c82960d9427d5972eb702c917b3b838ecf89

1 files changed, 13 insertions, 5 deletions

diff --git a/readpass.c b/readpass.c
index 03197a0af..4172bbc56 100644
--- a/readpass.c
+++ b/readpass.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: readpass.c,v 1.59 2019/12/06 02:55:21 djm Exp $ */
+/* $OpenBSD: readpass.c,v 1.60 2019/12/06 03:06:08 djm Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  *
@@ -48,7 +48,7 @@
 #include "uidswap.h"
 
 static char *
-ssh_askpass(char *askpass, const char *msg)
+ssh_askpass(char *askpass, const char *msg, const char *env_hint)
 {
         pid_t pid, ret;
         size_t len;
@@ -75,7 +75,8 @@ ssh_askpass(char *askpass, const char *msg)
                 close(p[0]);
                 if (dup2(p[1], STDOUT_FILENO) == -1)
                         fatal("%s: dup2: %s", __func__, strerror(errno));
-                setenv("SSH_ASKPASS_PROMPT", "confirm", 1); /* hint to UI */
+                if (env_hint != NULL)
+                        setenv("SSH_ASKPASS_PROMPT", env_hint, 1);
                 execlp(askpass, askpass, msg, (char *)NULL);
                 fatal("%s: exec(%s): %s", __func__, askpass, strerror(errno));
         }
@@ -109,6 +110,9 @@ ssh_askpass(char *askpass, const char *msg)
         return pass;
 }
 
+/* private/internal read_passphrase flags */
+#define RP_ASK_PERMISSION       0x8000 /* pass hint to askpass for confirm UI */
+
 /*
  * Reads a passphrase from /dev/tty with echo turned off/on.  Returns the
  * passphrase (allocated with xmalloc).  Exits if EOF is encountered. If
@@ -120,6 +124,7 @@ read_passphrase(const char *prompt, int flags)
 {
         char cr = '\r', *askpass = NULL, *ret, buf[1024];
         int rppflags, use_askpass = 0, ttyfd;
+        const char *askpass_hint = NULL;
 
         rppflags = (flags & RP_ECHO) ? RPP_ECHO_ON : RPP_ECHO_OFF;
         if (flags & RP_USE_ASKPASS)
@@ -156,7 +161,9 @@ read_passphrase(const char *prompt, int flags)
                         askpass = getenv(SSH_ASKPASS_ENV);
                 else
                         askpass = _PATH_SSH_ASKPASS_DEFAULT;
-                if ((ret = ssh_askpass(askpass, prompt)) == NULL)
+                if ((flags & RP_ASK_PERMISSION) != 0)
+                        askpass_hint = "confirm";
+                if ((ret = ssh_askpass(askpass, prompt, askpass_hint)) == NULL)
                         if (!(flags & RP_ALLOW_EOF))
                                 return xstrdup("");
                 return ret;
@@ -184,7 +191,8 @@ ask_permission(const char *fmt, ...)
         vsnprintf(prompt, sizeof(prompt), fmt, args);
         va_end(args);
 
-        p = read_passphrase(prompt, RP_USE_ASKPASS|RP_ALLOW_EOF);
+        p = read_passphrase(prompt,
+            RP_USE_ASKPASS|RP_ALLOW_EOF|RP_ASK_PERMISSION);
         if (p != NULL) {
                 /*
                  * Accept empty responses and responses consisting