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authorLeo Famulari <leo@famulari.name>2020-03-07 08:30:52 -0500
committerLeo Famulari <leo@famulari.name>2020-03-07 16:37:25 -0500
commitbe3908fa145b72da9fd53a30751383a69fbedcb0 (patch)
treebd1ab6b14f8c8db43cf45ade1d23d15d0fc8f148 /gnu/packages/patches
parent83ac7cb42b7157a4317c1219521f6eb0046a9ed6 (diff)
gnu: QEMU: Fix CVE-2020-8608.
* gnu/packages/patches/qemu-CVE-2020-8608.patch: New file. * gnu/local.mk (dist_patch_DATA): Add it. * gnu/packages/virtualization.scm (qemu)[source]: Use it.
Diffstat (limited to 'gnu/packages/patches')
-rw-r--r--gnu/packages/patches/qemu-CVE-2020-8608.patch269
1 files changed, 269 insertions, 0 deletions
diff --git a/gnu/packages/patches/qemu-CVE-2020-8608.patch b/gnu/packages/patches/qemu-CVE-2020-8608.patch
new file mode 100644
index 0000000000..4cb017c795
--- /dev/null
+++ b/gnu/packages/patches/qemu-CVE-2020-8608.patch
@@ -0,0 +1,269 @@
+Fix CVE-2020-8608:
+
+https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-8608
+https://www.openwall.com/lists/oss-security/2020/02/06/2
+
+Patches copied from upstream dependency repository:
+
+https://gitlab.freedesktop.org/slirp/libslirp/commit/68ccb8021a838066f0951d4b2817eb6b6f10a843
+https://gitlab.freedesktop.org/slirp/libslirp/commit/30648c03b27fb8d9611b723184216cd3174b6775
+
+From 68ccb8021a838066f0951d4b2817eb6b6f10a843 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= <marcandre.lureau@redhat.com>
+Date: Mon, 27 Jan 2020 10:24:14 +0100
+Subject: [PATCH] tcp_emu: fix unsafe snprintf() usages
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Various calls to snprintf() assume that snprintf() returns "only" the
+number of bytes written (excluding terminating NUL).
+
+https://pubs.opengroup.org/onlinepubs/9699919799/functions/snprintf.html#tag_16_159_04
+
+"Upon successful completion, the snprintf() function shall return the
+number of bytes that would be written to s had n been sufficiently
+large excluding the terminating null byte."
+
+Before patch ce131029, if there isn't enough room in "m_data" for the
+"DCC ..." message, we overflow "m_data".
+
+After the patch, if there isn't enough room for the same, we don't
+overflow "m_data", but we set "m_len" out-of-bounds. The next time an
+access is bounded by "m_len", we'll have a buffer overflow then.
+
+Use slirp_fmt*() to fix potential OOB memory access.
+
+Reported-by: Laszlo Ersek <lersek@redhat.com>
+Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
+Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
+Message-Id: <20200127092414.169796-7-marcandre.lureau@redhat.com>
+---
+ src/tcp_subr.c | 44 +++++++++++++++++++++-----------------------
+ 1 file changed, 21 insertions(+), 23 deletions(-)
+
+diff --git a/src/tcp_subr.c b/src/tcp_subr.c
+index a699117..a72c86b 100644
+--- a/slirp/src/tcp_subr.c
++++ b/slirp/src/tcp_subr.c
+@@ -643,8 +643,7 @@ int tcp_emu(struct socket *so, struct mbuf *m)
+ NTOHS(n1);
+ NTOHS(n2);
+ m_inc(m, snprintf(NULL, 0, "%d,%d\r\n", n1, n2) + 1);
+- m->m_len = snprintf(m->m_data, M_ROOM(m), "%d,%d\r\n", n1, n2);
+- assert(m->m_len < M_ROOM(m));
++ m->m_len = slirp_fmt(m->m_data, M_ROOM(m), "%d,%d\r\n", n1, n2);
+ } else {
+ *eol = '\r';
+ }
+@@ -684,9 +683,9 @@ 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_FREEROOM(m),
+- "ORT %d,%d,%d,%d,%d,%d\r\n%s", n1, n2, n3, n4,
+- n5, n6, x == 7 ? buff : "");
++ m->m_len += slirp_fmt(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;
+ } else if ((bptr = (char *)strstr(m->m_data, "27 Entering")) != NULL) {
+ /*
+@@ -719,10 +718,9 @@ 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_FREEROOM(m),
+- "27 Entering Passive Mode (%d,%d,%d,%d,%d,%d)\r\n%s",
+- n1, n2, n3, n4, n5, n6, x == 7 ? buff : "");
+-
++ m->m_len += slirp_fmt(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 : "");
+ return 1;
+ }
+
+@@ -745,8 +743,8 @@ 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_ROOM(m),
+- "%d", ntohs(so->so_fport)) + 1;
++ m->m_len = slirp_fmt0(m->m_data, M_ROOM(m),
++ "%d", ntohs(so->so_fport));
+ return 1;
+
+ case EMU_IRC:
+@@ -765,10 +763,10 @@ 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_FREEROOM(m),
+- "DCC CHAT chat %lu %u%c\n",
+- (unsigned long)ntohl(so->so_faddr.s_addr),
+- ntohs(so->so_fport), 1);
++ m->m_len += slirp_fmt(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,
+ &n1) == 4) {
+ if ((so = tcp_listen(slirp, INADDR_ANY, 0, htonl(laddr),
+@@ -776,10 +774,10 @@ 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_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);
++ m->m_len += slirp_fmt(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,
+ &n1) == 4) {
+ if ((so = tcp_listen(slirp, INADDR_ANY, 0, htonl(laddr),
+@@ -787,10 +785,10 @@ 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_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);
++ m->m_len += slirp_fmt(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);
+ }
+ return 1;
+
+--
+2.25.1
+
+From 30648c03b27fb8d9611b723184216cd3174b6775 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= <marcandre.lureau@redhat.com>
+Date: Mon, 27 Jan 2020 10:24:09 +0100
+Subject: [PATCH] util: add slirp_fmt() helpers
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Various calls to snprintf() in libslirp assume that snprintf() returns
+"only" the number of bytes written (excluding terminating NUL).
+
+https://pubs.opengroup.org/onlinepubs/9699919799/functions/snprintf.html#tag_16_159_04
+
+"Upon successful completion, the snprintf() function shall return the
+number of bytes that would be written to s had n been sufficiently
+large excluding the terminating null byte."
+
+Introduce slirp_fmt() that handles several pathological cases the
+way libslirp usually expect:
+
+- treat error as fatal (instead of silently returning -1)
+
+- fmt0() will always \0 end
+
+- return the number of bytes actually written (instead of what would
+have been written, which would usually result in OOB later), including
+the ending \0 for fmt0()
+
+- warn if truncation happened (instead of ignoring)
+
+Other less common cases can still be handled with strcpy/snprintf() etc.
+
+Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
+Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
+Message-Id: <20200127092414.169796-2-marcandre.lureau@redhat.com>
+---
+ src/util.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
+ src/util.h | 3 +++
+ 2 files changed, 65 insertions(+)
+
+diff --git a/src/util.c b/src/util.c
+index e596087..e3b6257 100644
+--- a/slirp/src/util.c
++++ b/slirp/src/util.c
+@@ -364,3 +364,65 @@ void slirp_pstrcpy(char *buf, int buf_size, const char *str)
+ }
+ *q = '\0';
+ }
++
++static int slirp_vsnprintf(char *str, size_t size,
++ const char *format, va_list args)
++{
++ int rv = vsnprintf(str, size, format, args);
++
++ if (rv < 0) {
++ g_error("vsnprintf() failed: %s", g_strerror(errno));
++ }
++
++ return rv;
++}
++
++/*
++ * A snprintf()-like function that:
++ * - returns the number of bytes written (excluding optional \0-ending)
++ * - dies on error
++ * - warn on truncation
++ */
++int slirp_fmt(char *str, size_t size, const char *format, ...)
++{
++ va_list args;
++ int rv;
++
++ va_start(args, format);
++ rv = slirp_vsnprintf(str, size, format, args);
++ va_end(args);
++
++ if (rv > size) {
++ g_critical("vsnprintf() truncation");
++ }
++
++ return MIN(rv, size);
++}
++
++/*
++ * A snprintf()-like function that:
++ * - always \0-end (unless size == 0)
++ * - returns the number of bytes actually written, including \0 ending
++ * - dies on error
++ * - warn on truncation
++ */
++int slirp_fmt0(char *str, size_t size, const char *format, ...)
++{
++ va_list args;
++ int rv;
++
++ va_start(args, format);
++ rv = slirp_vsnprintf(str, size, format, args);
++ va_end(args);
++
++ if (rv >= size) {
++ g_critical("vsnprintf() truncation");
++ if (size > 0)
++ str[size - 1] = '\0';
++ rv = size;
++ } else {
++ rv += 1; /* include \0 */
++ }
++
++ return rv;
++}
+diff --git a/src/util.h b/src/util.h
+index e9c3073..5530c46 100644
+--- a/slirp/src/util.h
++++ b/slirp/src/util.h
+@@ -181,4 +181,7 @@ static inline int slirp_socket_set_fast_reuse(int fd)
+
+ void slirp_pstrcpy(char *buf, int buf_size, const char *str);
+
++int slirp_fmt(char *str, size_t size, const char *format, ...);
++int slirp_fmt0(char *str, size_t size, const char *format, ...);
++
+ #endif
+--
+2.25.1
+