[Xen-changelog] [qemu-xen stable-4.6] display: cirrus: ignore source pitch value as needed in blit_is_unsafe

[patchbot@xxxxxxx]

commit 57901a6693118bbe072ce149806e475c6f4bad5b
Author:     Bruce Rogers <brogers@xxxxxxxx>
AuthorDate: Tue Feb 21 10:54:38 2017 -0800
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Tue Feb 21 11:08:50 2017 -0800

    display: cirrus: ignore source pitch value as needed in blit_is_unsafe
    
    Commit 4299b90 added a check which is too broad, given that the source
    pitch value is not required to be initialized for solid fill operations.
    This patch refines the blit_is_unsafe() check to ignore source pitch in
    that case. After applying the above commit as a security patch, we
    noticed the SLES 11 SP4 guest gui failed to initialize properly.
    
    Signed-off-by: Bruce Rogers <brogers@xxxxxxxx>
    Message-id: 20170109203520.5619-1-brogers@xxxxxxxx
    Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
---
 hw/display/cirrus_vga.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
index 8f86142..e2ee46a 100644
--- a/hw/display/cirrus_vga.c
+++ b/hw/display/cirrus_vga.c
@@ -286,7 +286,7 @@ static bool blit_region_is_unsafe(struct CirrusVGAState *s,
     return false;
 }
 
-static bool blit_is_unsafe(struct CirrusVGAState *s)
+static bool blit_is_unsafe(struct CirrusVGAState *s, bool dst_only)
 {
     /* should be the case, see cirrus_bitblt_start */
     assert(s->cirrus_blt_width > 0);
@@ -300,6 +300,9 @@ static bool blit_is_unsafe(struct CirrusVGAState *s)
                               s->cirrus_blt_dstaddr & s->cirrus_addr_mask)) {
         return true;
     }
+    if (dst_only) {
+        return false;
+    }
     if (blit_region_is_unsafe(s, s->cirrus_blt_srcpitch,
                               s->cirrus_blt_srcaddr & s->cirrus_addr_mask)) {
         return true;
@@ -665,7 +668,7 @@ static int cirrus_bitblt_common_patterncopy(CirrusVGAState 
* s,
 
     dst = s->vga.vram_ptr + (s->cirrus_blt_dstaddr & s->cirrus_addr_mask);
 
-    if (blit_is_unsafe(s))
+    if (blit_is_unsafe(s, false))
         return 0;
 
     (*s->cirrus_rop) (s, dst, src,
@@ -683,7 +686,7 @@ static int cirrus_bitblt_solidfill(CirrusVGAState *s, int 
blt_rop)
 {
     cirrus_fill_t rop_func;
 
-    if (blit_is_unsafe(s)) {
+    if (blit_is_unsafe(s, true)) {
         return 0;
     }
     rop_func = cirrus_fill[rop_to_index[blt_rop]][s->cirrus_blt_pixelwidth - 
1];
@@ -782,7 +785,7 @@ static void cirrus_do_copy(CirrusVGAState *s, int dst, int 
src, int w, int h)
 
 static int cirrus_bitblt_videotovideo_copy(CirrusVGAState * s)
 {
-    if (blit_is_unsafe(s))
+    if (blit_is_unsafe(s, false))
         return 0;
 
     cirrus_do_copy(s, s->cirrus_blt_dstaddr - s->vga.start_addr,
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#stable-4.6

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