On 200804 2320, Helge Deller wrote: > Hi Alexander, > > * Alexander Bulekov <alx...@bu.edu>: > > I applied this series and it fixes most of the problems I saw before. > > I still see a few crashes - I made issues for them on launchpad: > > https://bugs.launchpad.net/qemu/+bug/1890310 > > https://bugs.launchpad.net/qemu/+bug/1890311
> > https://bugs.launchpad.net/qemu/+bug/1890312 Hi Helge, I can still reproduce this one ^^^ I'll fuzz it some more, but so far I am not finding anything else. Thanks! -Alex > > Thanks for testing! > Below is the updated patch which fixes all of the issues you reported so > far. Can you please test again? > If you like you can pull all changes from > https://github.com/hdeller/qemu-hppa/commits/target-hppa > > Thanks! > Helge > > --------------- > > From ee31d3aa9dd91cde3a4df8fce97239a0ff26f7cc Mon Sep 17 00:00:00 2001 > From: Helge Deller <del...@gmx.de> > Date: Tue, 4 Aug 2020 15:35:38 +0200 > Subject: [PATCH] hw/display/artist: Prevent out of VRAM buffer accesses > > Simplify bounds checks by changing some parameters like row or column > numbers to become unsigned instead of signed. > With that we can check if the calculated offset is bigger than the size > of the VRAM region and bail out if not. > > Reported-by: LLVM libFuzzer > Reported-by: Alexander Bulekov <alx...@bu.edu> > Buglink: https://bugs.launchpad.net/qemu/+bug/1880326 > Buglink: https://bugs.launchpad.net/qemu/+bug/1890310 > Buglink: https://bugs.launchpad.net/qemu/+bug/1890311 > Buglink: https://bugs.launchpad.net/qemu/+bug/1890312 > Signed-off-by: Helge Deller <del...@gmx.de> > > diff --git a/hw/display/artist.c b/hw/display/artist.c > index 47de17b9e9..66a230bbd5 100644 > --- a/hw/display/artist.c > +++ b/hw/display/artist.c > @@ -35,9 +35,9 @@ > struct vram_buffer { > MemoryRegion mr; > uint8_t *data; > - int size; > - int width; > - int height; > + unsigned int size; > + unsigned int width; > + unsigned int height; > }; > > typedef struct ARTISTState { > @@ -203,14 +203,18 @@ static int16_t artist_get_y(uint32_t reg) > } > > static void artist_invalidate_lines(struct vram_buffer *buf, > - int starty, int height) > + unsigned int starty, unsigned int height) > { > - int start = starty * buf->width; > - int size = height * buf->width; > + unsigned int start, size; > > - if (start + size <= buf->size) { > - memory_region_set_dirty(&buf->mr, start, size); > + if (starty >= buf->height) { > + return; > } > + > + start = starty * buf->width; > + size = MIN(height * buf->width, buf->size - start); > + > + memory_region_set_dirty(&buf->mr, start, size); > } > > static int vram_write_pix_per_transfer(ARTISTState *s) > @@ -274,15 +278,15 @@ static artist_rop_t artist_get_op(ARTISTState *s) > } > > static void artist_rop8(ARTISTState *s, struct vram_buffer *buf, > - int offset, uint8_t val) > + unsigned int offset, uint8_t val) > { > const artist_rop_t op = artist_get_op(s); > uint8_t plane_mask; > uint8_t *dst; > > - if (offset < 0 || offset >= buf->size) { > + if (offset >= buf->size) { > qemu_log_mask(LOG_GUEST_ERROR, > - "rop8 offset:%d bufsize:%u\n", offset, buf->size); > + "rop8 offset:%u bufsize:%u\n", offset, buf->size); > return; > } > dst = buf->data + offset; > @@ -294,8 +298,7 @@ static void artist_rop8(ARTISTState *s, struct > vram_buffer *buf, > break; > > case ARTIST_ROP_COPY: > - *dst &= ~plane_mask; > - *dst |= val & plane_mask; > + *dst = (*dst & ~plane_mask) | (val & plane_mask); > break; > > case ARTIST_ROP_XOR: > @@ -349,7 +352,8 @@ static void vram_bit_write(ARTISTState *s, int posx, int > posy, bool incr_x, > { > struct vram_buffer *buf; > uint32_t vram_bitmask = s->vram_bitmask; > - int mask, i, pix_count, pix_length, offset, width; > + int mask, i, pix_count, pix_length; > + unsigned int offset, width; > uint8_t *data8, *p; > > pix_count = vram_write_pix_per_transfer(s); > @@ -394,7 +398,9 @@ static void vram_bit_write(ARTISTState *s, int posx, int > posy, bool incr_x, > > case 3: > if (s->cmap_bm_access) { > - *(uint32_t *)(p + offset) = data; > + if (offset + 3 < buf->size) { > + *(uint32_t *)(p + offset) = data; > + } > break; > } > data8 = (uint8_t *)&data; > @@ -464,12 +470,14 @@ static void vram_bit_write(ARTISTState *s, int posx, > int posy, bool incr_x, > } > } > > -static void block_move(ARTISTState *s, int source_x, int source_y, int > dest_x, > - int dest_y, int width, int height) > +static void block_move(ARTISTState *s, > + unsigned int source_x, unsigned int source_y, > + unsigned int dest_x, unsigned int dest_y, > + unsigned int width, unsigned int height) > { > struct vram_buffer *buf; > int line, endline, lineincr, startcolumn, endcolumn, columnincr, column; > - uint32_t dst, src; > + unsigned int dst, src; > > trace_artist_block_move(source_x, source_y, dest_x, dest_y, width, > height); > > @@ -481,6 +489,12 @@ static void block_move(ARTISTState *s, int source_x, int > source_y, int dest_x, > } > > buf = &s->vram_buffer[ARTIST_BUFFER_AP]; > + if (height > buf->height) { > + height = buf->height; > + } > + if (width > buf->width) { > + width = buf->width; > + } > > if (dest_y > source_y) { > /* move down */ > @@ -507,24 +521,27 @@ static void block_move(ARTISTState *s, int source_x, > int source_y, int dest_x, > } > > for ( ; line != endline; line += lineincr) { > - src = source_x + ((line + source_y) * buf->width); > - dst = dest_x + ((line + dest_y) * buf->width); > + src = source_x + ((line + source_y) * buf->width) + startcolumn; > + dst = dest_x + ((line + dest_y) * buf->width) + startcolumn; > > for (column = startcolumn; column != endcolumn; column += > columnincr) { > - if (dst + column > buf->size || src + column > buf->size) { > + if (dst >= buf->size || src >= buf->size) { > continue; > } > - artist_rop8(s, buf, dst + column, buf->data[src + column]); > + artist_rop8(s, buf, dst, buf->data[src]); > + src += columnincr; > + dst += columnincr; > } > } > > artist_invalidate_lines(buf, dest_y, height); > } > > -static void fill_window(ARTISTState *s, int startx, int starty, > - int width, int height) > +static void fill_window(ARTISTState *s, > + unsigned int startx, unsigned int starty, > + unsigned int width, unsigned int height) > { > - uint32_t offset; > + unsigned int offset; > uint8_t color = artist_get_color(s); > struct vram_buffer *buf; > int x, y; > @@ -561,7 +578,9 @@ static void fill_window(ARTISTState *s, int startx, int > starty, > artist_invalidate_lines(buf, starty, height); > } > > -static void draw_line(ARTISTState *s, int x1, int y1, int x2, int y2, > +static void draw_line(ARTISTState *s, > + unsigned int x1, unsigned int y1, > + unsigned int x2, unsigned int y2, > bool update_start, int skip_pix, int max_pix) > { > struct vram_buffer *buf = &s->vram_buffer[ARTIST_BUFFER_AP]; > @@ -636,7 +655,7 @@ static void draw_line(ARTISTState *s, int x1, int y1, int > x2, int y2, > color = artist_get_color(s); > > do { > - int ofs; > + unsigned int ofs; > > if (c1) { > ofs = x * s->width + y; > @@ -768,13 +787,13 @@ static void font_write16(ARTISTState *s, uint16_t val) > uint16_t mask; > int i; > > - int startx = artist_get_x(s->vram_start); > - int starty = artist_get_y(s->vram_start) + s->font_write_pos_y; > - int offset = starty * s->width + startx; > + unsigned int startx = artist_get_x(s->vram_start); > + unsigned int starty = artist_get_y(s->vram_start) + s->font_write_pos_y; > + unsigned int offset = starty * s->width + startx; > > buf = &s->vram_buffer[ARTIST_BUFFER_AP]; > > - if (offset + 16 > buf->size) { > + if (offset + 16 >= buf->size) { > return; > } > > @@ -1138,7 +1157,7 @@ static void artist_vram_write(void *opaque, hwaddr > addr, uint64_t val, > struct vram_buffer *buf; > int posy = (addr >> 11) & 0x3ff; > int posx = addr & 0x7ff; > - uint32_t offset; > + unsigned int offset; > trace_artist_vram_write(size, addr, val); > > if (s->cmap_bm_access) { > @@ -1161,16 +1180,22 @@ static void artist_vram_write(void *opaque, hwaddr > addr, uint64_t val, > offset = posy * buf->width + posx; > switch (size) { > case 4: > - *(uint32_t *)(buf->data + offset) = be32_to_cpu(val); > - memory_region_set_dirty(&buf->mr, offset, 4); > + if (offset + 3 < buf->size) { > + *(uint32_t *)(buf->data + offset) = be32_to_cpu(val); > + memory_region_set_dirty(&buf->mr, offset, 4); > + } > break; > case 2: > - *(uint16_t *)(buf->data + offset) = be16_to_cpu(val); > - memory_region_set_dirty(&buf->mr, offset, 2); > + if (offset + 1 < buf->size) { > + *(uint16_t *)(buf->data + offset) = be16_to_cpu(val); > + memory_region_set_dirty(&buf->mr, offset, 2); > + } > break; > case 1: > - *(uint8_t *)(buf->data + offset) = val; > - memory_region_set_dirty(&buf->mr, offset, 1); > + if (offset < buf->size) { > + *(uint8_t *)(buf->data + offset) = val; > + memory_region_set_dirty(&buf->mr, offset, 1); > + } > break; > default: > break;
