diff options
Diffstat (limited to 'app-emulation/qemu/files/qemu-2.8.0-CVE-2017-2620.patch')
-rw-r--r-- | app-emulation/qemu/files/qemu-2.8.0-CVE-2017-2620.patch | 56 |
1 files changed, 56 insertions, 0 deletions
diff --git a/app-emulation/qemu/files/qemu-2.8.0-CVE-2017-2620.patch b/app-emulation/qemu/files/qemu-2.8.0-CVE-2017-2620.patch new file mode 100644 index 000000000000..e2a98012d7cc --- /dev/null +++ b/app-emulation/qemu/files/qemu-2.8.0-CVE-2017-2620.patch @@ -0,0 +1,56 @@ +From: Gerd Hoffmann <kraxel@redhat.com> +Subject: [PATCH 3/3] cirrus: add blit_is_unsafe call to cirrus_bitblt_cputovideo + +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. + +The missing blit width check allows to overflow cirrus_bltbuf, +with the attractive target cirrus_srcptr (current cirrus_bltbuf write +position) being located right after cirrus_bltbuf in CirrusVGAState. + +Due to cirrus emulation writing cirrus_bltbuf bytewise the attacker +hasn't full control over cirrus_srcptr though, only one byte can be +changed. Once the first byte has been modified further writes land +elsewhere. + +[ This is CVE-2017-2620 / XSA-209 - Ian Jackson ] + +Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> +--- + hw/display/cirrus_vga.c | 8 ++++++++ + 1 file changed, 8 insertions(+) + +diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c +index 0e47cf8..a093dc8 100644 +--- a/hw/display/cirrus_vga.c ++++ b/hw/display/cirrus_vga.c +@@ -899,6 +899,10 @@ static int cirrus_bitblt_cputovideo(CirrusVGAState * s) + { + int w; + ++ if (blit_is_unsafe(s)) { ++ return 0; ++ } ++ + s->cirrus_blt_mode &= ~CIRRUS_BLTMODE_MEMSYSSRC; + s->cirrus_srcptr = &s->cirrus_bltbuf[0]; + s->cirrus_srcptr_end = &s->cirrus_bltbuf[0]; +@@ -924,6 +928,10 @@ 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); +-- +1.8.3.1 + |