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authorGerd Hoffmann <kraxel@redhat.com>2017-02-08 11:18:36 +0100
committerGerd Hoffmann <kraxel@redhat.com>2017-02-24 14:35:50 +0100
commit92f2b88cea48c6aeba8de568a45f2ed958f3c298 (patch)
tree6ed759495bfcf73c74481e0d8cc01c7d33cc8d21 /hw/display/cirrus_vga.c
parent10f25e4844cb9b3f02fb032f88051dd5b65b4206 (diff)
cirrus: add blit_is_unsafe call to cirrus_bitblt_cputovideo (CVE-2017-2620)
CIRRUS_BLTMODE_MEMSYSSRC blits do NOT check blit destination and blit width, at all. Oops. Fix it. Security impact: high. The missing blit destination check allows to write to host memory. Basically same as CVE-2014-8106 for the other blit variants. Cc: qemu-stable@nongnu.org Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Diffstat (limited to 'hw/display/cirrus_vga.c')
-rw-r--r--hw/display/cirrus_vga.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
index 1deb52070a..b9e7cb1df1 100644
--- a/hw/display/cirrus_vga.c
+++ b/hw/display/cirrus_vga.c
@@ -900,6 +900,10 @@ static int cirrus_bitblt_cputovideo(CirrusVGAState * s)
{
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 @@ static int cirrus_bitblt_cputovideo(CirrusVGAState * s)
}
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);