[arch-commits] Commit in spice/trunk (CVE-2013-4282.patch PKGBUILD)

[Tobias Powalowski]

    Date: Monday, November 18, 2013 @ 08:36:08
  Author: tpowa
Revision: 199888

upgpkg: spice 0.12.4-3

#37767 fix CVE-2013-4282

Added:
  spice/trunk/CVE-2013-4282.patch
Modified:
  spice/trunk/PKGBUILD

---------------------+
 CVE-2013-4282.patch |  104 ++++++++++++++++++++++++++++++++++++++++++++++++++
 PKGBUILD            |   13 ++++--
 2 files changed, 114 insertions(+), 3 deletions(-)

Added: CVE-2013-4282.patch
===================================================================
--- CVE-2013-4282.patch	                        (rev 0)
+++ CVE-2013-4282.patch	2013-11-18 07:36:08 UTC (rev 199888)
@@ -0,0 +1,104 @@
+From 8af619009660b24e0b41ad26b30289eea288fcc2 Mon Sep 17 00:00:00 2001
+From: Christophe Fergeau <cfergeau at redhat.com>
+Date: Fri, 23 Aug 2013 09:29:44 +0000
+Subject: Fix buffer overflow when decrypting client SPICE ticket
+
+reds_handle_ticket uses a fixed size 'password' buffer for the decrypted
+password whose size is SPICE_MAX_PASSWORD_LENGTH. However,
+RSA_private_decrypt which we call for the decryption expects the
+destination buffer to be at least RSA_size(link->tiTicketing.rsa)
+bytes long. On my spice-server build, SPICE_MAX_PASSWORD_LENGTH
+is 60 while RSA_size() is 128, so we end up overflowing 'password'
+when using long passwords (this was reproduced using the string:
+'fullscreen=1proxy=#enter proxy here; e.g spice_proxy = http://[proxy]:[port]'
+as a password).
+
+When the overflow occurs, QEMU dies with:
+*** stack smashing detected ***: qemu-system-x86_64 terminated
+
+This commit ensures we use a corectly sized 'password' buffer,
+and that it's correctly nul-terminated so that we can use strcmp
+instead of strncmp. To keep using strncmp, we'd need to figure out
+which one of 'password' and 'taTicket.password' is the smaller buffer,
+and use that size.
+
+This fixes rhbz#999839
+---
+diff --git a/server/reds.c b/server/reds.c
+index 892d247..2a0002b 100644
+--- a/server/reds.c
++++ b/server/reds.c
+@@ -1926,39 +1926,59 @@ static void reds_handle_link(RedLinkInfo *link)
+ static void reds_handle_ticket(void *opaque)
+ {
+     RedLinkInfo *link = (RedLinkInfo *)opaque;
+-    char password[SPICE_MAX_PASSWORD_LENGTH];
++    char *password;
+     time_t ltime;
++    int password_size;
+ 
+     //todo: use monotonic time
+     time(&ltime);
+-    RSA_private_decrypt(link->tiTicketing.rsa_size,
+-                        link->tiTicketing.encrypted_ticket.encrypted_data,
+-                        (unsigned char *)password, link->tiTicketing.rsa, RSA_PKCS1_OAEP_PADDING);
++    if (RSA_size(link->tiTicketing.rsa) < SPICE_MAX_PASSWORD_LENGTH) {
++        spice_warning("RSA modulus size is smaller than SPICE_MAX_PASSWORD_LENGTH (%d < %d), "
++                      "SPICE ticket sent from client may be truncated",
++                      RSA_size(link->tiTicketing.rsa), SPICE_MAX_PASSWORD_LENGTH);
++    }
++
++    password = g_malloc0(RSA_size(link->tiTicketing.rsa) + 1);
++    password_size = RSA_private_decrypt(link->tiTicketing.rsa_size,
++                                        link->tiTicketing.encrypted_ticket.encrypted_data,
++                                        (unsigned char *)password,
++                                        link->tiTicketing.rsa,
++                                        RSA_PKCS1_OAEP_PADDING);
++    if (password_size == -1) {
++        spice_warning("failed to decrypt RSA encrypted password: %s",
++                      ERR_error_string(ERR_get_error(), NULL));
++        goto error;
++    }
++    password[password_size] = '\0';
+ 
+     if (ticketing_enabled && !link->skip_auth) {
+         int expired =  taTicket.expiration_time < ltime;
+ 
+         if (strlen(taTicket.password) == 0) {
+-            reds_send_link_result(link, SPICE_LINK_ERR_PERMISSION_DENIED);
+             spice_warning("Ticketing is enabled, but no password is set. "
+-                        "please set a ticket first");
+-            reds_link_free(link);
+-            return;
++                          "please set a ticket first");
++            goto error;
+         }
+ 
+-        if (expired || strncmp(password, taTicket.password, SPICE_MAX_PASSWORD_LENGTH) != 0) {
++        if (expired || strcmp(password, taTicket.password) != 0) {
+             if (expired) {
+                 spice_warning("Ticket has expired");
+             } else {
+                 spice_warning("Invalid password");
+             }
+-            reds_send_link_result(link, SPICE_LINK_ERR_PERMISSION_DENIED);
+-            reds_link_free(link);
+-            return;
++            goto error;
+         }
+     }
+ 
+     reds_handle_link(link);
++    goto end;
++
++error:
++    reds_send_link_result(link, SPICE_LINK_ERR_PERMISSION_DENIED);
++    reds_link_free(link);
++
++end:
++    g_free(password);
+ }
+ 
+ static inline void async_read_clear_handlers(AsyncRead *obj)
+--
+cgit v0.9.0.2-2-gbebe

Modified: PKGBUILD
===================================================================
--- PKGBUILD	2013-11-18 07:25:14 UTC (rev 199887)
+++ PKGBUILD	2013-11-18 07:36:08 UTC (rev 199888)
@@ -4,7 +4,7 @@
 
 pkgname=spice
 pkgver=0.12.4
-pkgrel=2
+pkgrel=3
 pkgdesc="SPICE client and server"
 arch=('i686' 'x86_64')
 url="http://spice-space.org"
@@ -11,9 +11,14 @@
 license=('LGPL2.1')
 depends=(alsa-lib celt0.5.1 libcacard libjpeg-turbo libsasl libxinerama libxfixes libxrandr pixman)
 makedepends=(python2-pyparsing qemu spice-protocol)
-source=(http://spice-space.org/download/releases/$pkgname-$pkgver.tar.bz2)
-md5sums=('325b1c42ce24e75de45a75876b73a8bd')
+source=(http://spice-space.org/download/releases/$pkgname-$pkgver.tar.bz2
+        CVE-2013-4282.patch)
 
+prepare() {
+  cd "$srcdir/$pkgname-$pkgver"
+  patch -Np1 -i ../CVE-2013-4282.patch
+}
+
 build() {
   cd "$srcdir/$pkgname-$pkgver"
   PYTHON=python2 ./configure --prefix=/usr --disable-static --enable-smartcard --enable-client
@@ -24,3 +29,5 @@
   cd "$srcdir/$pkgname-$pkgver"
   make DESTDIR="$pkgdir/" install
 }
+md5sums=('325b1c42ce24e75de45a75876b73a8bd'
+         '24a1648e7c684b4444d7921b5534767e')