From 7e450cb80a476b5f96e9c9da67e21ffebcc4b375 Mon Sep 17 00:00:00 2001 From: Daniel Stenberg Date: Thu, 16 Apr 2026 10:09:59 +0200 Subject: [PATCH] libssh2: allocate libssh2-friendly memory in kbd_callback The function libssh2_userauth_keyboard_interactive_ex() calls the callback and is documented to call free() on the memory returned to libssh2 from the callback. libcurl can therefore not use the regular curlx_strdup() for this, as that is not compatible in debug builds or when curl_global_init_mem() is used. Fixes #21336 Closes #21338 --- lib/vssh/libssh2.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/lib/vssh/libssh2.c b/lib/vssh/libssh2.c index e4d35bbdcf..4e2a72269f 100644 --- a/lib/vssh/libssh2.c +++ b/lib/vssh/libssh2.c @@ -148,7 +148,9 @@ static void kbd_callback(const char *name, int name_len, #endif /* CURL_LIBSSH2_DEBUG */ if(num_prompts == 1) { struct connectdata *conn = data->conn; - responses[0].text = curlx_strdup(conn->passwd); + /* this function must allocate memory that can be freed by libssh2, which + uses the LIBSSH2_FREE_FUNC callback */ + responses[0].text = Curl_cstrdup(conn->passwd); responses[0].length = responses[0].text == NULL ? 0 : curlx_uztoui(strlen(conn->passwd)); }