[pve-devel] [PATCH] pve-qemu-kvm: fix VENOM qemu security flaw (CVE-2015-3456)

Stefan Priebe s.priebe at profihost.ag
Wed May 13 19:14:17 CEST 2015


Signed-off-by: Stefan Priebe <s.priebe at profihost.ag>
---
 ...he-fifo-access-to-be-in-bounds-of-the-all.patch |   87 ++++++++++++++++++++
 debian/patches/series                              |    1 +
 2 files changed, 88 insertions(+)
 create mode 100644 debian/patches/0001-fdc-force-the-fifo-access-to-be-in-bounds-of-the-all.patch

diff --git a/debian/patches/0001-fdc-force-the-fifo-access-to-be-in-bounds-of-the-all.patch b/debian/patches/0001-fdc-force-the-fifo-access-to-be-in-bounds-of-the-all.patch
new file mode 100644
index 0000000..d28b0ea
--- /dev/null
+++ b/debian/patches/0001-fdc-force-the-fifo-access-to-be-in-bounds-of-the-all.patch
@@ -0,0 +1,87 @@
+From 8cb8ea32396f52e01cdb38c00b5b7f5a0141f97f Mon Sep 17 00:00:00 2001
+From: Petr Matousek <pmatouse at redhat.com>
+Date: Wed, 6 May 2015 09:48:59 +0200
+Subject: [PATCH] fdc: force the fifo access to be in bounds of the allocated
+ buffer
+
+During processing of certain commands such as FD_CMD_READ_ID and
+FD_CMD_DRIVE_SPECIFICATION_COMMAND the fifo memory access could
+get out of bounds leading to memory corruption with values coming
+from the guest.
+
+Fix this by making sure that the index is always bounded by the
+allocated memory.
+
+This is CVE-2015-3456.
+
+Signed-off-by: Petr Matousek <pmatouse at redhat.com>
+Reviewed-by: John Snow <jsnow at redhat.com>
+Signed-off-by: John Snow <jsnow at redhat.com>
+(cherry picked from commit e907746266721f305d67bc0718795fedee2e824c)
+Signed-off-by: Stefan Priebe <s.priebe at profihost.ag>
+---
+ hw/block/fdc.c |   17 +++++++++++------
+ 1 file changed, 11 insertions(+), 6 deletions(-)
+
+diff --git a/hw/block/fdc.c b/hw/block/fdc.c
+index 739a03e..1168e8c 100644
+--- a/hw/block/fdc.c
++++ b/hw/block/fdc.c
+@@ -1512,7 +1512,7 @@ static uint32_t fdctrl_read_data(FDCtrl *fdctrl)
+ {
+     FDrive *cur_drv;
+     uint32_t retval = 0;
+-    int pos;
++    uint32_t pos;
+ 
+     cur_drv = get_cur_drv(fdctrl);
+     fdctrl->dsr &= ~FD_DSR_PWRDOWN;
+@@ -1521,8 +1521,8 @@ static uint32_t fdctrl_read_data(FDCtrl *fdctrl)
+         return 0;
+     }
+     pos = fdctrl->data_pos;
++    pos %= FD_SECTOR_LEN;
+     if (fdctrl->msr & FD_MSR_NONDMA) {
+-        pos %= FD_SECTOR_LEN;
+         if (pos == 0) {
+             if (fdctrl->data_pos != 0)
+                 if (!fdctrl_seek_to_next_sect(fdctrl, cur_drv)) {
+@@ -1867,10 +1867,13 @@ static void fdctrl_handle_option(FDCtrl *fdctrl, int direction)
+ static void fdctrl_handle_drive_specification_command(FDCtrl *fdctrl, int direction)
+ {
+     FDrive *cur_drv = get_cur_drv(fdctrl);
++    uint32_t pos;
+ 
+-    if (fdctrl->fifo[fdctrl->data_pos - 1] & 0x80) {
++    pos = fdctrl->data_pos - 1;
++    pos %= FD_SECTOR_LEN;
++    if (fdctrl->fifo[pos] & 0x80) {
+         /* Command parameters done */
+-        if (fdctrl->fifo[fdctrl->data_pos - 1] & 0x40) {
++        if (fdctrl->fifo[pos] & 0x40) {
+             fdctrl->fifo[0] = fdctrl->fifo[1];
+             fdctrl->fifo[2] = 0;
+             fdctrl->fifo[3] = 0;
+@@ -1970,7 +1973,7 @@ static uint8_t command_to_handler[256];
+ static void fdctrl_write_data(FDCtrl *fdctrl, uint32_t value)
+ {
+     FDrive *cur_drv;
+-    int pos;
++    uint32_t pos;
+ 
+     /* Reset mode */
+     if (!(fdctrl->dor & FD_DOR_nRESET)) {
+@@ -2019,7 +2022,9 @@ static void fdctrl_write_data(FDCtrl *fdctrl, uint32_t value)
+     }
+ 
+     FLOPPY_DPRINTF("%s: %02x\n", __func__, value);
+-    fdctrl->fifo[fdctrl->data_pos++] = value;
++    pos = fdctrl->data_pos++;
++    pos %= FD_SECTOR_LEN;
++    fdctrl->fifo[pos] = value;
+     if (fdctrl->data_pos == fdctrl->data_len) {
+         /* We now have all parameters
+          * and will be able to treat the command
+-- 
+1.7.10.4
+
diff --git a/debian/patches/series b/debian/patches/series
index 51b8c2f..436a07d 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -34,3 +34,4 @@ virtio-balloon-dimmfix2.patch
 virtio-balloon-dimmfix3.patch
 add-qmp-get-link-status.patch
 virtio-scsi_fix_assert.patch
+0001-fdc-force-the-fifo-access-to-be-in-bounds-of-the-all.patch
-- 
1.7.10.4



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