diff options
Diffstat (limited to 'gnu/packages/patches/qemu-CVE-2020-8608.patch')
| -rw-r--r-- | gnu/packages/patches/qemu-CVE-2020-8608.patch | 269 |
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 + |