qemu: fix CVE-2021-3507 fdc heap buffer overflow in DMA read data transfers

(From OE-Core rev: 39a9f2056d4794dc75390b9a4a903c1745545095)

Signed-off-by: Vivek Kumbhar <vkumbhar@mvista.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 88 insertions, 0 deletions

diff --git a/meta/recipes-devtools/qemu/qemu.inc b/meta/recipes-devtools/qemu/qemu.inc
index a915b54c1a..fff2c87780 100644
--- a/meta/recipes-devtools/qemu/qemu.inc
+++ b/meta/recipes-devtools/qemu/qemu.inc
@@ -114,6 +114,7 @@ SRC_URI = "https://download.qemu.org/${BPN}-${PV}.tar.xz \
            file://CVE-2021-3750.patch \
            file://CVE-2021-3638.patch \
            file://CVE-2021-20196.patch \
+           file://CVE-2021-3507.patch \
            "
 UPSTREAM_CHECK_REGEX = "qemu-(?P<pver>\d+(\.\d+)+)\.tar"
 
diff --git a/meta/recipes-devtools/qemu/qemu/CVE-2021-3507.patch b/meta/recipes-devtools/qemu/qemu/CVE-2021-3507.patch
new file mode 100644
index 0000000000..4ff3413f8e
--- /dev/null
+++ b/meta/recipes-devtools/qemu/qemu/CVE-2021-3507.patch
@@ -0,0 +1,87 @@
+From defac5e2fbddf8423a354ff0454283a2115e1367 Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= <philmd@redhat.com>
+Date: Thu, 18 Nov 2021 12:57:32 +0100
+Subject: [PATCH] hw/block/fdc: Prevent end-of-track overrun (CVE-2021-3507)
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Per the 82078 datasheet, if the end-of-track (EOT byte in
+the FIFO) is more than the number of sectors per side, the
+command is terminated unsuccessfully:
+
+* 5.2.5 DATA TRANSFER TERMINATION
+
+  The 82078 supports terminal count explicitly through
+  the TC pin and implicitly through the underrun/over-
+  run and end-of-track (EOT) functions. For full sector
+  transfers, the EOT parameter can define the last
+  sector to be transferred in a single or multisector
+  transfer. If the last sector to be transferred is a par-
+  tial sector, the host can stop transferring the data in
+  mid-sector, and the 82078 will continue to complete
+  the sector as if a hardware TC was received. The
+  only difference between these implicit functions and
+  TC is that they return "abnormal termination" result
+  status. Such status indications can be ignored if they
+  were expected.
+
+* 6.1.3 READ TRACK
+
+  This command terminates when the EOT specified
+  number of sectors have been read. If the 82078
+  does not find an I D Address Mark on the diskette
+  after the second· occurrence of a pulse on the
+  INDX# pin, then it sets the IC code in Status Regis-
+  ter 0 to "01" (Abnormal termination), sets the MA bit
+  in Status Register 1 to "1", and terminates the com-
+  mand.
+
+* 6.1.6 VERIFY
+
+  Refer to Table 6-6 and Table 6-7 for information
+  concerning the values of MT and EC versus SC and
+  EOT value.
+
+* Table 6·6. Result Phase Table
+
+* Table 6-7. Verify Command Result Phase Table
+
+Fix by aborting the transfer when EOT > # Sectors Per Side.
+
+Cc: qemu-stable@nongnu.org
+Cc: Hervé Poussineau <hpoussin@reactos.org>
+Fixes: baca51faff0 ("floppy driver: disk geometry auto detect")
+Reported-by: Alexander Bulekov <alxndr@bu.edu>
+Resolves: https://gitlab.com/qemu-project/qemu/-/issues/339
+Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
+Message-Id: <20211118115733.4038610-2-philmd@redhat.com>
+Reviewed-by: Hanna Reitz <hreitz@redhat.com>
+Signed-off-by: Kevin Wolf <kwolf@redhat.com>
+
+Upstream-Status: Backport [https://github.com/qemu/qemu/commit/defac5e2fbddf8423a354ff0454283a2115e1367]
+CVE: CVE-2021-3507
+Signed-off-by: Vivek Kumbhar <vkumbhar@mvista.com>
+---
+ hw/block/fdc.c | 8 ++++++++
+ 1 file changed, 8 insertions(+)
+
+diff --git a/hw/block/fdc.c b/hw/block/fdc.c
+index 347875a0cdae..57bb355794a9 100644
+--- a/hw/block/fdc.c
++++ b/hw/block/fdc.c
+@@ -1530,6 +1530,14 @@ static void fdctrl_start_transfer(FDCtrl *fdctrl, int direction)
+         int tmp;
+         fdctrl->data_len = 128 << (fdctrl->fifo[5] > 7 ? 7 : fdctrl->fifo[5]);
+         tmp = (fdctrl->fifo[6] - ks + 1);
++        if (tmp < 0) {
++            FLOPPY_DPRINTF("invalid EOT: %d\n", tmp);
++            fdctrl_stop_transfer(fdctrl, FD_SR0_ABNTERM, FD_SR1_MA, 0x00);
++            fdctrl->fifo[3] = kt;
++            fdctrl->fifo[4] = kh;
++            fdctrl->fifo[5] = ks;
++            return;
++        }
+         if (fdctrl->fifo[0] & 0x80)
+             tmp += fdctrl->fifo[6];
+         fdctrl->data_len *= tmp;