From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45472) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1V2SI9-0003eL-9T for qemu-devel@nongnu.org; Thu, 25 Jul 2013 16:37:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1V2SI6-0004tJ-SO for qemu-devel@nongnu.org; Thu, 25 Jul 2013 16:37:41 -0400 Sender: fluxion From: Michael Roth Date: Thu, 25 Jul 2013 15:37:24 -0500 Message-Id: <1374784644-29078-4-git-send-email-mdroth@linux.vnet.ibm.com> In-Reply-To: <1374784644-29078-1-git-send-email-mdroth@linux.vnet.ibm.com> References: <1374784644-29078-1-git-send-email-mdroth@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH 3/3] qga: escape cmdline args when registering win32 service (CVE-2013-2231) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: pmatouse@redhat.com, aliguori@us.ibm.com, lersek@redhat.com, qemu-stable@nongnu.org, lveyde@redhat.com From: Laszlo Ersek Reported-by: Lev Veyde Reviewed-by: Eric Blake Signed-off-by: Laszlo Ersek Signed-off-by: Michael Roth --- qga/service-win32.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 74 insertions(+), 5 deletions(-) diff --git a/qga/service-win32.c b/qga/service-win32.c index 1cf81fc..aef41f0 100644 --- a/qga/service-win32.c +++ b/qga/service-win32.c @@ -35,6 +35,68 @@ static int printf_win_error(const char *text) return n; } +/* Windows command line escaping. Based on + * and + * . + * + * The caller is responsible for initializing @buffer; prior contents are lost. + */ +static const char *win_escape_arg(const char *to_escape, GString *buffer) +{ + size_t backslash_count; + const char *c; + + /* open with a double quote */ + g_string_assign(buffer, "\""); + + backslash_count = 0; + for (c = to_escape; *c != '\0'; ++c) { + switch (*c) { + case '\\': + /* The meaning depends on the first non-backslash character coming + * up. + */ + ++backslash_count; + break; + + case '"': + /* We must escape each pending backslash, then escape the double + * quote. This creates a case of "odd number of backslashes [...] + * followed by a double quotation mark". + */ + while (backslash_count) { + --backslash_count; + g_string_append(buffer, "\\\\"); + } + g_string_append(buffer, "\\\""); + break; + + default: + /* Any pending backslashes are without special meaning, flush them. + * "Backslashes are interpreted literally, unless they immediately + * precede a double quotation mark." + */ + while (backslash_count) { + --backslash_count; + g_string_append_c(buffer, '\\'); + } + g_string_append_c(buffer, *c); + } + } + + /* We're about to close with a double quote in string delimiter role. + * Double all pending backslashes, creating a case of "even number of + * backslashes [...] followed by a double quotation mark". + */ + while (backslash_count) { + --backslash_count; + g_string_append(buffer, "\\\\"); + } + g_string_append_c(buffer, '"'); + + return buffer->str; +} + int ga_install_service(const char *path, const char *logfile, const char *state_dir) { @@ -42,6 +104,7 @@ int ga_install_service(const char *path, const char *logfile, SC_HANDLE manager; SC_HANDLE service; TCHAR module_fname[MAX_PATH]; + GString *esc; GString *cmdline; SERVICE_DESCRIPTION desc = { (char *)QGA_SERVICE_DESCRIPTION }; @@ -50,17 +113,22 @@ int ga_install_service(const char *path, const char *logfile, return EXIT_FAILURE; } - cmdline = g_string_new(module_fname); - g_string_append(cmdline, " -d"); + esc = g_string_new(""); + cmdline = g_string_new(""); + + g_string_append_printf(cmdline, "%s -d", + win_escape_arg(module_fname, esc)); if (path) { - g_string_append_printf(cmdline, " -p %s", path); + g_string_append_printf(cmdline, " -p %s", win_escape_arg(path, esc)); } if (logfile) { - g_string_append_printf(cmdline, " -l %s -v", logfile); + g_string_append_printf(cmdline, " -l %s -v", + win_escape_arg(logfile, esc)); } if (state_dir) { - g_string_append_printf(cmdline, " -t %s", state_dir); + g_string_append_printf(cmdline, " -t %s", + win_escape_arg(state_dir, esc)); } g_debug("service's cmdline: %s", cmdline->str); @@ -89,6 +157,7 @@ out_manager: out_strings: g_string_free(cmdline, TRUE); + g_string_free(esc, TRUE); return ret; } -- 1.7.9.5