commit 63f495beb4007de5444614125fd6fd178ca6e2b1
author Peter Maydell <peter.maydell@linaro.org> Fri Feb 24 13:55:26 2017 +0000
committer Peter Maydell <peter.maydell@linaro.org> Fri Feb 24 13:55:26 2017 +0000
tree 4fa239a295b3c99663523b60760f94c9dfd9f9bb
parent 5842b55fd403ac0a16443aad58a8cf6d4c10cf77
parent 92f2b88cea48c6aeba8de568a45f2ed958f3c298

Merge remote-tracking branch 'remotes/kraxel/tags/pull-cve-2017-2620-20170224-1' into staging

cirrus: add blit_is_unsafe call to cirrus_bitblt_cputovideo (CVE-2017-2620)

# gpg: Signature made Fri 24 Feb 2017 13:42:39 GMT
# gpg:                using RSA key 0x4CB6D8EED3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>"
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>"
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>"
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* remotes/kraxel/tags/pull-cve-2017-2620-20170224-1:
  cirrus: add blit_is_unsafe call to cirrus_bitblt_cputovideo (CVE-2017-2620)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

hw/display/cirrus_vga.c

diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
index 1deb520..b9e7cb1 100644
--- a/hw/display/cirrus_vga.c
+++ b/hw/display/cirrus_vga.c
@@ -900,6 +900,10 @@
 {
     int w;
 
+    if (blit_is_unsafe(s, true)) {
+        return 0;
+    }
+
     s->cirrus_blt_mode &= ~CIRRUS_BLTMODE_MEMSYSSRC;
     s->cirrus_srcptr = &s->cirrus_bltbuf[0];
     s->cirrus_srcptr_end = &s->cirrus_bltbuf[0];
@@ -925,6 +929,10 @@
 	}
         s->cirrus_srccounter = s->cirrus_blt_srcpitch * s->cirrus_blt_height;
     }
+
+    /* the blit_is_unsafe call above should catch this */
+    assert(s->cirrus_blt_srcpitch <= CIRRUS_BLTBUFSIZE);
+
     s->cirrus_srcptr = s->cirrus_bltbuf;
     s->cirrus_srcptr_end = s->cirrus_bltbuf + s->cirrus_blt_srcpitch;
     cirrus_update_memory_access(s);