diff options
| author | Philippe Mathieu-Daudé <f4bug@amsat.org> | 2020-05-23 21:15:15 +0200 |
|---|---|---|
| committer | Helge Deller <deller@gmx.de> | 2020-08-26 23:04:00 +0200 |
| commit | b87a7355de04a2771c11824ea791802c052c979c (patch) | |
| tree | 7e69cd2959bc8a3f3f84f621f3e52eea278803b3 /hw/display | |
| parent | b899fe41ceb9c684fa135a081f4c9749400a61d3 (diff) | |
| download | focaccia-qemu-b87a7355de04a2771c11824ea791802c052c979c.tar.gz focaccia-qemu-b87a7355de04a2771c11824ea791802c052c979c.zip | |
hw/display/artist: Check offset in draw_line to avoid buffer over-run
Invalid I/O writes can craft an offset out of the vram_buffer range. We avoid: Program terminated with signal SIGSEGV, Segmentation fault. 284 *dst &= ~plane_mask; (gdb) bt #0 0x000055d5dccdc5c0 in artist_rop8 (s=0x55d5defee510, dst=0x7f8e84ed8216 <error: Cannot access memory at address 0x7f8e84ed8216>, val=0 '\000') at hw/display/artist.c:284 #1 0x000055d5dccdcf83 in fill_window (s=0x55d5defee510, startx=22, starty=5674, width=65, height=5697) at hw/display/artist.c:551 #2 0x000055d5dccddfb9 in artist_reg_write (opaque=0x55d5defee510, addr=1051140, val=4265537, size=4) at hw/display/artist.c:902 #3 0x000055d5dcb42a7c in memory_region_write_accessor (mr=0x55d5defeea10, addr=1051140, value=0x7ffe57db08c8, size=4, shift=0, mask=4294967295, attrs=...) at memory.c:483 Reported-by: LLVM libFuzzer Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Helge Deller <deller@gmx.de>
Diffstat (limited to 'hw/display')
| -rw-r--r-- | hw/display/artist.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/hw/display/artist.c b/hw/display/artist.c index de56200dbf..a206afe641 100644 --- a/hw/display/artist.c +++ b/hw/display/artist.c @@ -555,7 +555,7 @@ static void fill_window(ARTISTState *s, int startx, int starty, static void draw_line(ARTISTState *s, int x1, int y1, int x2, int y2, bool update_start, int skip_pix, int max_pix) { - struct vram_buffer *buf; + struct vram_buffer *buf = &s->vram_buffer[ARTIST_BUFFER_AP]; uint8_t color; int dx, dy, t, e, x, y, incy, diago, horiz; bool c1; @@ -563,6 +563,12 @@ static void draw_line(ARTISTState *s, int x1, int y1, int x2, int y2, trace_artist_draw_line(x1, y1, x2, y2); + if (x1 * y1 >= buf->size || x2 * y2 >= buf->size) { + qemu_log_mask(LOG_GUEST_ERROR, + "draw_line (%d,%d) (%d,%d)\n", x1, y1, x2, y2); + return; + } + if (update_start) { s->vram_start = (x2 << 16) | y2; } @@ -620,7 +626,6 @@ static void draw_line(ARTISTState *s, int x1, int y1, int x2, int y2, x = x1; y = y1; color = artist_get_color(s); - buf = &s->vram_buffer[ARTIST_BUFFER_AP]; do { if (c1) { |