Subject: [PATCH 1/2] gnu: QEMU: Fix CVE-2020-{7039,7211}.
From: Leo Famulari <[email-masked]>
To: [email-masked]
Date: Tue, 21 Jan 2020 13:55:51 -0500
List-Id: <debbugs-submit.debbugs.gnu.org>

* gnu/packages/patches/qemu-CVE-2020-7039.patch,
gnu/packages/patches/qemu-CVE-2020-7211.patch: New files.
* gnu/local.mk (dist_patch_DATA): Add them.
* gnu/packages/virtualization.scm (qemu)[source]: Use them.
---
 gnu/local.mk                                  |   2 +
 gnu/packages/patches/qemu-CVE-2020-7039.patch | 173 ++++++++++++++++++
 gnu/packages/patches/qemu-CVE-2020-7211.patch |  49 +++++
 gnu/packages/virtualization.scm               |   2 +
 4 files changed, 226 insertions(+)
 create mode 100644 gnu/packages/patches/qemu-CVE-2020-7039.patch
 create mode 100644 gnu/packages/patches/qemu-CVE-2020-7211.patch

diff --git a/gnu/local.mk b/gnu/local.mk
index 626d91ce62..1a01a87c40 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -1334,6 +1334,8 @@ dist_patch_DATA =						\
   %D%/packages/patches/python-unittest2-remove-argparse.patch	\
   %D%/packages/patches/python-waitress-fix-tests.patch		\
   %D%/packages/patches/qemu-glibc-2.27.patch 			\
+  %D%/packages/patches/qemu-CVE-2020-7039.patch			\
+  %D%/packages/patches/qemu-CVE-2020-7211.patch			\
   %D%/packages/patches/qt4-ldflags.patch			\
   %D%/packages/patches/qtbase-use-TZDIR.patch			\
   %D%/packages/patches/qtscript-disable-tests.patch		\
diff --git a/gnu/packages/patches/qemu-CVE-2020-7039.patch b/gnu/packages/patches/qemu-CVE-2020-7039.patch
new file mode 100644
index 0000000000..ffebda68ab
--- /dev/null
+++ b/gnu/packages/patches/qemu-CVE-2020-7039.patch
@@ -0,0 +1,173 @@
+Fix CVE-2020-7039:
+
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-7039
+
+Patches copied from upstream dependency repository:
+
+https://gitlab.freedesktop.org/slirp/libslirp/commit/2655fffed7a9e765bcb4701dd876e9dab975f289
+https://gitlab.freedesktop.org/slirp/libslirp/commit/ce131029d6d4a405cb7d3ac6716d03e58fb4a5d9
+https://gitlab.freedesktop.org/slirp/libslirp/commit/82ebe9c370a0e2970fb5695aa19aa5214a6a1c80
+
+From 2655fffed7a9e765bcb4701dd876e9dab975f289 Mon Sep 17 00:00:00 2001
+From: Samuel Thibault <[email-masked]>
+Date: Wed, 8 Jan 2020 00:58:48 +0100
+Subject: [PATCH] tcp_emu: Fix oob access
+
+The main loop only checks for one available byte, while we sometimes
+need two bytes.
+---
+ CHANGELOG.md   | 1 +
+ src/tcp_subr.c | 7 +++++++
+ 2 files changed, 8 insertions(+)
+
+#diff --git a/CHANGELOG.md b/CHANGELOG.md
+#index 00d0ce2..5cf94a8 100644
+#--- a/CHANGELOG.md
+#+++ b/CHANGELOG.md
+#@@ -20,6 +20,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
+# ### Fixed
+# 
+#  - ncsi: fix checksum OOB memory access
+#+ - `tcp_emu()`: fix OOB accesses
+# 
+# ## [4.1.0] - 2019-12-02
+# 
+diff --git a/src/tcp_subr.c b/src/tcp_subr.c
+index 382aa38..9c1bdec 100644
+--- a/slirp/src/tcp_subr.c
++++ b/slirp/src/tcp_subr.c
+@@ -871,6 +871,9 @@ int tcp_emu(struct socket *so, struct mbuf *m)
+                 break;
+ 
+             case 5:
++                if (bptr == m->m_data + m->m_len - 1)
++                        return 1; /* We need two bytes */
++
+                 /*
+                  * The difference between versions 1.0 and
+                  * 2.0 is here. For future versions of
+@@ -886,6 +889,10 @@ int tcp_emu(struct socket *so, struct mbuf *m)
+                 /* This is the field containing the port
+                  * number that RA-player is listening to.
+                  */
++
++                if (bptr == m->m_data + m->m_len - 1)
++                        return 1; /* We need two bytes */
++
+                 lport = (((uint8_t *)bptr)[0] << 8) + ((uint8_t *)bptr)[1];
+                 if (lport < 6970)
+                     lport += 256; /* don't know why */
+-- 
+2.24.1
+
+From ce131029d6d4a405cb7d3ac6716d03e58fb4a5d9 Mon Sep 17 00:00:00 2001
+From: Prasad J Pandit <[email-masked]>
+Date: Thu, 9 Jan 2020 15:12:27 +0530
+Subject: [PATCH] slirp: use correct size while emulating IRC commands
+
+While emulating IRC DCC commands, tcp_emu() uses 'mbuf' size
+'m->m_size' to write DCC commands via snprintf(3). This may
+lead to OOB write access, because 'bptr' points somewhere in
+the middle of 'mbuf' buffer, not at the start. Use M_FREEROOM(m)
+size to avoid OOB access.
+
+Reported-by: Vishnu Dev TJ <[email-masked]>
+Signed-off-by: Prasad J Pandit <[email-masked]>
+Reviewed-by: Samuel Thibault <[email-masked]>
+Message-Id: <[email-masked]>
+---
+ src/tcp_subr.c | 11 ++++++-----
+ 1 file changed, 6 insertions(+), 5 deletions(-)
+
+diff --git a/src/tcp_subr.c b/src/tcp_subr.c
+index 9c1bdec..ee7a938 100644
+--- a/slirp/src/tcp_subr.c
++++ b/slirp/src/tcp_subr.c
+@@ -763,7 +763,8 @@ int tcp_emu(struct socket *so, struct mbuf *m)
+                 return 1;
+             }
+             m->m_len = bptr - m->m_data; /* Adjust length */
+-            m->m_len += snprintf(bptr, m->m_size, "DCC CHAT chat %lu %u%c\n",
++            m->m_len += snprintf(bptr, M_FREEROOM(m),
++                                 "DCC CHAT chat %lu %u%c\n",
+                                  (unsigned long)ntohl(so->so_faddr.s_addr),
+                                  ntohs(so->so_fport), 1);
+         } else if (sscanf(bptr, "DCC SEND %256s %u %u %u", buff, &laddr, &lport,
+@@ -773,8 +774,8 @@ int tcp_emu(struct socket *so, struct mbuf *m)
+                 return 1;
+             }
+             m->m_len = bptr - m->m_data; /* Adjust length */
+-            m->m_len +=
+-                snprintf(bptr, m->m_size, "DCC SEND %s %lu %u %u%c\n", buff,
++            m->m_len += snprintf(bptr, M_FREEROOM(m),
++                         "DCC SEND %s %lu %u %u%c\n", buff,
+                          (unsigned long)ntohl(so->so_faddr.s_addr),
+                          ntohs(so->so_fport), n1, 1);
+         } else if (sscanf(bptr, "DCC MOVE %256s %u %u %u", buff, &laddr, &lport,
+@@ -784,8 +785,8 @@ int tcp_emu(struct socket *so, struct mbuf *m)
+                 return 1;
+             }
+             m->m_len = bptr - m->m_data; /* Adjust length */
+-            m->m_len +=
+-                snprintf(bptr, m->m_size, "DCC MOVE %s %lu %u %u%c\n", buff,
++            m->m_len += snprintf(bptr, M_FREEROOM(m),
++                         "DCC MOVE %s %lu %u %u%c\n", buff,
+                          (unsigned long)ntohl(so->so_faddr.s_addr),
+                          ntohs(so->so_fport), n1, 1);
+         }
+-- 
+2.24.1
+
+From 82ebe9c370a0e2970fb5695aa19aa5214a6a1c80 Mon Sep 17 00:00:00 2001
+From: Prasad J Pandit <[email-masked]>
+Date: Thu, 9 Jan 2020 15:12:28 +0530
+Subject: [PATCH] slirp: use correct size while emulating commands
+
+While emulating services in tcp_emu(), it uses 'mbuf' size
+'m->m_size' to write commands via snprintf(3). Use M_FREEROOM(m)
+size to avoid possible OOB access.
+
+Signed-off-by: Prasad J Pandit <[email-masked]>
+Signed-off-by: Samuel Thibault <[email-masked]>
+Message-Id: <[email-masked]>
+---
+ src/tcp_subr.c | 9 ++++-----
+ 1 file changed, 4 insertions(+), 5 deletions(-)
+
+diff --git a/src/tcp_subr.c b/src/tcp_subr.c
+index ee7a938..177dfd2 100644
+--- a/slirp/src/tcp_subr.c
++++ b/slirp/src/tcp_subr.c
+@@ -681,7 +681,7 @@ int tcp_emu(struct socket *so, struct mbuf *m)
+             n4 = (laddr & 0xff);
+ 
+             m->m_len = bptr - m->m_data; /* Adjust length */
+-            m->m_len += snprintf(bptr, m->m_size - m->m_len,
++            m->m_len += snprintf(bptr, M_FREEROOM(m),
+                                  "ORT %d,%d,%d,%d,%d,%d\r\n%s", n1, n2, n3, n4,
+                                  n5, n6, x == 7 ? buff : "");
+             return 1;
+@@ -716,8 +716,7 @@ int tcp_emu(struct socket *so, struct mbuf *m)
+             n4 = (laddr & 0xff);
+ 
+             m->m_len = bptr - m->m_data; /* Adjust length */
+-            m->m_len +=
+-                snprintf(bptr, m->m_size - m->m_len,
++            m->m_len += snprintf(bptr, M_FREEROOM(m),
+                          "27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%s",
+                          n1, n2, n3, n4, n5, n6, x == 7 ? buff : "");
+ 
+@@ -743,8 +742,8 @@ int tcp_emu(struct socket *so, struct mbuf *m)
+         if (m->m_data[m->m_len - 1] == '\0' && lport != 0 &&
+             (so = tcp_listen(slirp, INADDR_ANY, 0, so->so_laddr.s_addr,
+                              htons(lport), SS_FACCEPTONCE)) != NULL)
+-            m->m_len =
+-                snprintf(m->m_data, m->m_size, "%d", ntohs(so->so_fport)) + 1;
++            m->m_len = snprintf(m->m_data, M_ROOM(m),
++                                "%d", ntohs(so->so_fport)) + 1;
+         return 1;
+ 
+     case EMU_IRC:
+-- 
+2.24.1
+
diff --git a/gnu/packages/patches/qemu-CVE-2020-7211.patch b/gnu/packages/patches/qemu-CVE-2020-7211.patch
new file mode 100644
index 0000000000..2885dda411
--- /dev/null
+++ b/gnu/packages/patches/qemu-CVE-2020-7211.patch
@@ -0,0 +1,49 @@
+Fix CVE-2020-7211:
+
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-7211
+
+Patch copied from upstream dependency repository:
+
+https://gitlab.freedesktop.org/slirp/libslirp/commit/14ec36e107a8c9af7d0a80c3571fe39b291ff1d4
+
+From 14ec36e107a8c9af7d0a80c3571fe39b291ff1d4 Mon Sep 17 00:00:00 2001
+From: Prasad J Pandit <[email-masked]>
+Date: Mon, 13 Jan 2020 17:44:31 +0530
+Subject: [PATCH] slirp: tftp: restrict relative path access
+
+tftp restricts relative or directory path access on Linux systems.
+Apply same restrictions on Windows systems too. It helps to avoid
+directory traversal issue.
+
+Fixes: https://bugs.launchpad.net/qemu/+bug/1812451
+Reported-by: Peter Maydell <[email-masked]>
+Signed-off-by: Prasad J Pandit <[email-masked]>
+Reviewed-by: Samuel Thibault <[email-masked]>
+Message-Id: <[email-masked]>
+---
+ src/tftp.c | 9 +++++++--
+ 1 file changed, 7 insertions(+), 2 deletions(-)
+
+diff --git a/src/tftp.c b/src/tftp.c
+index 093c2e0..e52e71b 100644
+--- a/slirp/src/tftp.c
++++ b/slirp/src/tftp.c
+@@ -344,8 +344,13 @@ static void tftp_handle_rrq(Slirp *slirp, struct sockaddr_storage *srcsas,
+     k += 6; /* skipping octet */
+ 
+     /* do sanity checks on the filename */
+-    if (!strncmp(req_fname, "../", 3) ||
+-        req_fname[strlen(req_fname) - 1] == '/' || strstr(req_fname, "/../")) {
++    if (
++#ifdef G_OS_WIN32
++        strstr(req_fname, "..\\") ||
++        req_fname[strlen(req_fname) - 1] == '\\' ||
++#endif
++        strstr(req_fname, "../") ||
++        req_fname[strlen(req_fname) - 1] == '/') {
+         tftp_send_error(spt, 2, "Access violation", tp);
+         return;
+     }
+-- 
+2.24.1
+
diff --git a/gnu/packages/virtualization.scm b/gnu/packages/virtualization.scm
index 51ba3c602a..1874cf3d9f 100644
--- a/gnu/packages/virtualization.scm
+++ b/gnu/packages/virtualization.scm
@@ -114,6 +114,8 @@
              (method url-fetch)
              (uri (string-append "https://download.qemu.org/qemu-"
                                  version ".tar.xz"))
+             (patches (search-patches "qemu-CVE-2020-7039.patch"
+                                      "qemu-CVE-2020-7211.patch"))
              (sha256
               (base32
                "1lm1jndfpc5sydwrxyiz5sms414zkcg9jdl0zx318qbjsayxnvzd"))))
-- 
2.25.0