diff options
| author | Gerd Hoffmann <kraxel@redhat.com> | 2017-02-08 11:18:36 +0100 |
|---|---|---|
| committer | Gerd Hoffmann <kraxel@redhat.com> | 2017-02-24 14:35:50 +0100 |
| commit | 92f2b88cea48c6aeba8de568a45f2ed958f3c298 (patch) | |
| tree | 6ed759495bfcf73c74481e0d8cc01c7d33cc8d21 /hw | |
| parent | 10f25e4844cb9b3f02fb032f88051dd5b65b4206 (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')
| -rw-r--r-- | hw/display/cirrus_vga.c | 8 |
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); |