Re: [OE-core] [hardknott][PATCH 3/8] qemu: CVE-2021-3595

[Sakib Sajal <sakib.sajal@windriver.com>]

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Please disregard this set of patches, somehow it failed to send the 
first 2 and one in the middle. sending a V3.

Sorry for inconvenience
On 2022-01-13 7:06 p.m., Sakib Sajal wrote:
> Signed-off-by: Sakib Sajal <sakib.sajal@windriver.com>
> ---
>   meta/recipes-devtools/qemu/qemu.inc           |   2 +
>   .../qemu/qemu/CVE-2021-3595_1.patch           |  41 +++
>   .../qemu/qemu/CVE-2021-3595_2.patch           | 253 ++++++++++++++++++
>   3 files changed, 296 insertions(+)
>   create mode 100644 meta/recipes-devtools/qemu/qemu/CVE-2021-3595_1.patch
>   create mode 100644 meta/recipes-devtools/qemu/qemu/CVE-2021-3595_2.patch
>
> diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc
> index 6b544a4344..811bdff426 100644
> --- a/meta/recipes-devtools/qemu/qemu.inc
> +++ b/meta/recipes-devtools/qemu/qemu.inc
> @@ -74,6 +74,8 @@ SRC_URI = "https://download.qemu.org/${BPN}-${PV}.tar.xz \
>              file://CVE-2021-3592_2.patch \
>              file://CVE-2021-3592_3.patch \
>              file://CVE-2021-3593.patch \
> +           file://CVE-2021-3595_1.patch \
> +           file://CVE-2021-3595_2.patch \
>              "
>   UPSTREAM_CHECK_REGEX = "qemu-(?P<pver>\d+(\.\d+)+)\.tar"
>   
> diff --git a/meta/recipes-devtools/qemu/qemu/CVE-2021-3595_1.patch b/meta/recipes-devtools/qemu/qemu/CVE-2021-3595_1.patch
> new file mode 100644
> index 0000000000..aefaff01cf
> --- /dev/null
> +++ b/meta/recipes-devtools/qemu/qemu/CVE-2021-3595_1.patch
> @@ -0,0 +1,41 @@
> +From 6b62a09d6c264cb84f560a418beb027f47bc5069 Mon Sep 17 00:00:00 2001
> +From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= <marcandre.lureau@redhat.com>
> +Date: Fri, 4 Jun 2021 16:34:30 +0400
> +Subject: [PATCH 05/12] tftp: check tftp_input buffer size
> +MIME-Version: 1.0
> +Content-Type: text/plain; charset=UTF-8
> +Content-Transfer-Encoding: 8bit
> +
> +Fixes: CVE-2021-3595
> +Fixes: https://gitlab.freedesktop.org/slirp/libslirp/-/issues/46
> +
> +Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> +
> +Upstream-Status: Backport
> +CVE: CVE-2021-3595
> +
> +Signed-off-by: Sakib Sajal <sakib.sajal@windriver.com>
> +---
> + slirp/src/tftp.c | 6 +++++-
> + 1 file changed, 5 insertions(+), 1 deletion(-)
> +
> +diff --git a/slirp/src/tftp.c b/slirp/src/tftp.c
> +index c6950ee10..e06911d42 100644
> +--- a/slirp/src/tftp.c
> ++++ b/slirp/src/tftp.c
> +@@ -446,7 +446,11 @@ static void tftp_handle_error(Slirp *slirp, struct sockaddr_storage *srcsas,
> +
> + void tftp_input(struct sockaddr_storage *srcsas, struct mbuf *m)
> + {
> +-    struct tftp_t *tp = (struct tftp_t *)m->m_data;
> ++    struct tftp_t *tp = mtod_check(m, offsetof(struct tftp_t, x.tp_buf));
> ++
> ++    if (tp == NULL) {
> ++        return;
> ++    }
> +
> +     switch (ntohs(tp->tp_op)) {
> +     case TFTP_RRQ:
> +--
> +2.31.1
> +
> diff --git a/meta/recipes-devtools/qemu/qemu/CVE-2021-3595_2.patch b/meta/recipes-devtools/qemu/qemu/CVE-2021-3595_2.patch
> new file mode 100644
> index 0000000000..1ffa6ca988
> --- /dev/null
> +++ b/meta/recipes-devtools/qemu/qemu/CVE-2021-3595_2.patch
> @@ -0,0 +1,253 @@
> +From d71caef98e331268519578fc0437e2ac02586940 Mon Sep 17 00:00:00 2001
> +From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= <marcandre.lureau@redhat.com>
> +Date: Fri, 4 Jun 2021 20:01:20 +0400
> +Subject: [PATCH 06/12] tftp: introduce a header structure
> +MIME-Version: 1.0
> +Content-Type: text/plain; charset=UTF-8
> +Content-Transfer-Encoding: 8bit
> +
> +Instead of using a composed structure and potentially reading past the
> +incoming buffer, use a different structure for the header.
> +
> +Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> +
> +Upstream-Status: Backport
> +CVE: CVE-2021-3595
> +
> +Signed-off-by: Sakib Sajal <sakib.sajal@windriver.com>
> +---
> + slirp/src/tftp.c | 60 +++++++++++++++++++++++++-----------------------
> + slirp/src/tftp.h |  6 ++++-
> + 2 files changed, 36 insertions(+), 30 deletions(-)
> +
> +diff --git a/slirp/src/tftp.c b/slirp/src/tftp.c
> +index e06911d42..a19c889d3 100644
> +--- a/slirp/src/tftp.c
> ++++ b/slirp/src/tftp.c
> +@@ -50,7 +50,7 @@ static void tftp_session_terminate(struct tftp_session *spt)
> + }
> +
> + static int tftp_session_allocate(Slirp *slirp, struct sockaddr_storage *srcsas,
> +-                                 struct tftp_t *tp)
> ++                                 struct tftphdr *hdr)
> + {
> +     struct tftp_session *spt;
> +     int k;
> +@@ -75,7 +75,7 @@ found:
> +     memcpy(&spt->client_addr, srcsas, sockaddr_size(srcsas));
> +     spt->fd = -1;
> +     spt->block_size = 512;
> +-    spt->client_port = tp->udp.uh_sport;
> ++    spt->client_port = hdr->udp.uh_sport;
> +     spt->slirp = slirp;
> +
> +     tftp_session_update(spt);
> +@@ -84,7 +84,7 @@ found:
> + }
> +
> + static int tftp_session_find(Slirp *slirp, struct sockaddr_storage *srcsas,
> +-                             struct tftp_t *tp)
> ++                             struct tftphdr *hdr)
> + {
> +     struct tftp_session *spt;
> +     int k;
> +@@ -94,7 +94,7 @@ static int tftp_session_find(Slirp *slirp, struct sockaddr_storage *srcsas,
> +
> +         if (tftp_session_in_use(spt)) {
> +             if (sockaddr_equal(&spt->client_addr, srcsas)) {
> +-                if (spt->client_port == tp->udp.uh_sport) {
> ++                if (spt->client_port == hdr->udp.uh_sport) {
> +                     return k;
> +                 }
> +             }
> +@@ -148,13 +148,13 @@ static struct tftp_t *tftp_prep_mbuf_data(struct tftp_session *spt,
> + }
> +
> + static void tftp_udp_output(struct tftp_session *spt, struct mbuf *m,
> +-                            struct tftp_t *recv_tp)
> ++                            struct tftphdr *hdr)
> + {
> +     if (spt->client_addr.ss_family == AF_INET6) {
> +         struct sockaddr_in6 sa6, da6;
> +
> +         sa6.sin6_addr = spt->slirp->vhost_addr6;
> +-        sa6.sin6_port = recv_tp->udp.uh_dport;
> ++        sa6.sin6_port = hdr->udp.uh_dport;
> +         da6.sin6_addr = ((struct sockaddr_in6 *)&spt->client_addr)->sin6_addr;
> +         da6.sin6_port = spt->client_port;
> +
> +@@ -163,7 +163,7 @@ static void tftp_udp_output(struct tftp_session *spt, struct mbuf *m,
> +         struct sockaddr_in sa4, da4;
> +
> +         sa4.sin_addr = spt->slirp->vhost_addr;
> +-        sa4.sin_port = recv_tp->udp.uh_dport;
> ++        sa4.sin_port = hdr->udp.uh_dport;
> +         da4.sin_addr = ((struct sockaddr_in *)&spt->client_addr)->sin_addr;
> +         da4.sin_port = spt->client_port;
> +
> +@@ -185,14 +185,14 @@ static int tftp_send_oack(struct tftp_session *spt, const char *keys[],
> +
> +     tp = tftp_prep_mbuf_data(spt, m);
> +
> +-    tp->tp_op = htons(TFTP_OACK);
> ++    tp->hdr.tp_op = htons(TFTP_OACK);
> +     for (i = 0; i < nb; i++) {
> +         n += slirp_fmt0(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%s", keys[i]);
> +         n += slirp_fmt0(tp->x.tp_buf + n, sizeof(tp->x.tp_buf) - n, "%u", values[i]);
> +     }
> +
> +-    m->m_len = G_SIZEOF_MEMBER(struct tftp_t, tp_op) + n;
> +-    tftp_udp_output(spt, m, recv_tp);
> ++    m->m_len = G_SIZEOF_MEMBER(struct tftp_t, hdr.tp_op) + n;
> ++    tftp_udp_output(spt, m, &recv_tp->hdr);
> +
> +     return 0;
> + }
> +@@ -213,21 +213,21 @@ static void tftp_send_error(struct tftp_session *spt, uint16_t errorcode,
> +
> +     tp = tftp_prep_mbuf_data(spt, m);
> +
> +-    tp->tp_op = htons(TFTP_ERROR);
> ++    tp->hdr.tp_op = htons(TFTP_ERROR);
> +     tp->x.tp_error.tp_error_code = htons(errorcode);
> +     slirp_pstrcpy((char *)tp->x.tp_error.tp_msg, sizeof(tp->x.tp_error.tp_msg),
> +                   msg);
> +
> +     m->m_len = sizeof(struct tftp_t) - (TFTP_BLOCKSIZE_MAX + 2) + 3 +
> +                strlen(msg) - sizeof(struct udphdr);
> +-    tftp_udp_output(spt, m, recv_tp);
> ++    tftp_udp_output(spt, m, &recv_tp->hdr);
> +
> + out:
> +     tftp_session_terminate(spt);
> + }
> +
> + static void tftp_send_next_block(struct tftp_session *spt,
> +-                                 struct tftp_t *recv_tp)
> ++                                 struct tftphdr *hdr)
> + {
> +     struct mbuf *m;
> +     struct tftp_t *tp;
> +@@ -241,7 +241,7 @@ static void tftp_send_next_block(struct tftp_session *spt,
> +
> +     tp = tftp_prep_mbuf_data(spt, m);
> +
> +-    tp->tp_op = htons(TFTP_DATA);
> ++    tp->hdr.tp_op = htons(TFTP_DATA);
> +     tp->x.tp_data.tp_block_nr = htons((spt->block_nr + 1) & 0xffff);
> +
> +     nobytes = tftp_read_data(spt, spt->block_nr, tp->x.tp_data.tp_buf,
> +@@ -259,7 +259,7 @@ static void tftp_send_next_block(struct tftp_session *spt,
> +
> +     m->m_len = sizeof(struct tftp_t) - (TFTP_BLOCKSIZE_MAX - nobytes) -
> +                sizeof(struct udphdr);
> +-    tftp_udp_output(spt, m, recv_tp);
> ++    tftp_udp_output(spt, m, hdr);
> +
> +     if (nobytes == spt->block_size) {
> +         tftp_session_update(spt);
> +@@ -282,12 +282,12 @@ static void tftp_handle_rrq(Slirp *slirp, struct sockaddr_storage *srcsas,
> +     int nb_options = 0;
> +
> +     /* check if a session already exists and if so terminate it */
> +-    s = tftp_session_find(slirp, srcsas, tp);
> ++    s = tftp_session_find(slirp, srcsas, &tp->hdr);
> +     if (s >= 0) {
> +         tftp_session_terminate(&slirp->tftp_sessions[s]);
> +     }
> +
> +-    s = tftp_session_allocate(slirp, srcsas, tp);
> ++    s = tftp_session_allocate(slirp, srcsas, &tp->hdr);
> +
> +     if (s < 0) {
> +         return;
> +@@ -413,29 +413,29 @@ static void tftp_handle_rrq(Slirp *slirp, struct sockaddr_storage *srcsas,
> +     }
> +
> +     spt->block_nr = 0;
> +-    tftp_send_next_block(spt, tp);
> ++    tftp_send_next_block(spt, &tp->hdr);
> + }
> +
> + static void tftp_handle_ack(Slirp *slirp, struct sockaddr_storage *srcsas,
> +-                            struct tftp_t *tp, int pktlen)
> ++                            struct tftphdr *hdr)
> + {
> +     int s;
> +
> +-    s = tftp_session_find(slirp, srcsas, tp);
> ++    s = tftp_session_find(slirp, srcsas, hdr);
> +
> +     if (s < 0) {
> +         return;
> +     }
> +
> +-    tftp_send_next_block(&slirp->tftp_sessions[s], tp);
> ++    tftp_send_next_block(&slirp->tftp_sessions[s], hdr);
> + }
> +
> + static void tftp_handle_error(Slirp *slirp, struct sockaddr_storage *srcsas,
> +-                              struct tftp_t *tp, int pktlen)
> ++                              struct tftphdr *hdr)
> + {
> +     int s;
> +
> +-    s = tftp_session_find(slirp, srcsas, tp);
> ++    s = tftp_session_find(slirp, srcsas, hdr);
> +
> +     if (s < 0) {
> +         return;
> +@@ -446,23 +446,25 @@ static void tftp_handle_error(Slirp *slirp, struct sockaddr_storage *srcsas,
> +
> + void tftp_input(struct sockaddr_storage *srcsas, struct mbuf *m)
> + {
> +-    struct tftp_t *tp = mtod_check(m, offsetof(struct tftp_t, x.tp_buf));
> ++    struct tftphdr *hdr = mtod_check(m, sizeof(struct tftphdr));
> +
> +-    if (tp == NULL) {
> ++    if (hdr == NULL) {
> +         return;
> +     }
> +
> +-    switch (ntohs(tp->tp_op)) {
> ++    switch (ntohs(hdr->tp_op)) {
> +     case TFTP_RRQ:
> +-        tftp_handle_rrq(m->slirp, srcsas, tp, m->m_len);
> ++        tftp_handle_rrq(m->slirp, srcsas,
> ++                        mtod(m, struct tftp_t *),
> ++                        m->m_len);
> +         break;
> +
> +     case TFTP_ACK:
> +-        tftp_handle_ack(m->slirp, srcsas, tp, m->m_len);
> ++        tftp_handle_ack(m->slirp, srcsas, hdr);
> +         break;
> +
> +     case TFTP_ERROR:
> +-        tftp_handle_error(m->slirp, srcsas, tp, m->m_len);
> ++        tftp_handle_error(m->slirp, srcsas, hdr);
> +         break;
> +     }
> + }
> +diff --git a/slirp/src/tftp.h b/slirp/src/tftp.h
> +index 6d75478e8..cafab03f2 100644
> +--- a/slirp/src/tftp.h
> ++++ b/slirp/src/tftp.h
> +@@ -20,9 +20,13 @@
> + #define TFTP_FILENAME_MAX 512
> + #define TFTP_BLOCKSIZE_MAX 1428
> +
> +-struct tftp_t {
> ++struct tftphdr {
> +     struct udphdr udp;
> +     uint16_t tp_op;
> ++} SLIRP_PACKED;
> ++
> ++struct tftp_t {
> ++    struct tftphdr hdr;
> +     union {
> +         struct {
> +             uint16_t tp_block_nr;
> +--
> +2.31.1
> +
>
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