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Tue, 04 Aug 2020 16:01:00 +0200 From: Helge Deller To: peter.maydell@linaro.org, qemu-devel@nongnu.org Subject: [PATCH v3 7/8] hw/display/artist: Refactor artist_rop8() to avoid buffer over-run Date: Tue, 4 Aug 2020 16:00:55 +0200 Message-Id: <20200804140056.7690-8-deller@gmx.de> X-Mailer: git-send-email 2.21.3 In-Reply-To: <20200804140056.7690-1-deller@gmx.de> References: <20200804140056.7690-1-deller@gmx.de> MIME-Version: 1.0 X-Provags-ID: V03:K1:yxMdJuG8/FfppgKDF8Hy9ctFW09MWRERHbwz3/K646kKa4vJdBa dVSGG0Wjp0KzOBzNx9UnXzms7e+OIfsHUQtlT4nZvO2RO56aWKTMmyNxZBL62vvEi7cSW9G zmAuccqEk1TcsMLgODS6ffQzWTG31aQbATSr09Tiq1jyqWlCiYaYZoiFH/+AxEPoE5XIS4k ym9RaaScbtobxqdoHbXvg== X-UI-Out-Filterresults: notjunk:1;V03:K0:mBOMpodSzkc=:1/D9+IgkGlc3KdhncNXAAB +gZp7Z7MbNjG0CKcHzlS9y8c3l1R4OVvHGUdEYtG7FTMMFPFMdlKIJzVN/oHf5NUu7ZGpUux6 PxoBGmSQ8STs7SJ9bw3ZRW6MeiMZ7WJ0gDY4wvau7c1cmvHX2ofKxW130DzLK/6IHOkIDKBP/ Bztxj01PGTsNl4eGTZAB6xy+AQZvmxtaGBMBzOEyFYY2M4M3uxXa+j3/FQ7zB9nWEcrCzKyA0 oJC2hTYtN3Vj/ST+l0QqNFQJL8+HaqcoKm3g6X7dkaf75cxfEl1RGLJlloSqB8f8NrtZoI6SD nPZqp00MWDB3k8uQmfaGmL1LpuC7+hEGilNPnEcdiM2V4PJdvOMpPS4iSIFnGv96Z+C6Lc+tK QWcB7fE6cRxfJmm6SKH6Q2j7UhQAjYTf9KUFQcK6+aeP4GkvoE3BlMJM2MXdpr4aIqyVBKstC sFQgOpQEwONU4xHdKEMrSGUpBnq2kJy8eyRnaRnSIQZBqHxH4kbDBd3JHVbU1J3Y4lTq4HCC7 ofHyHl/6gfxL7vU7UM4g4245cHwc85WoZF+zRoCnDNRTj4y9ddzXCNErWD1Cig7qCJT5CWLxj vyGpAikkSv+JdWcg9aN6z8S8Om7beZIhmlphd23u1+qfPc4E2c1QTfGfs+CXhaScZ95wDlAnf V8yOnTAaaIrzVfHTNzaEU+h1pRQf9FPhFOfSVcx+SA0fJNcfsnZ0warDbclFzba4qFNTZmH/8 gh582q1mqtGHJR9CqdK43fAOUalytWRJJJtTNsOi5G5M0yw5V5VwEm/IoPb3WRVXqHYPX6rwI g4S7CsF7pDSGMrdXqd4bvoaAKyBw2NHckIMRyX8kig9uk9bYjiDyn1LzDgL5YqeuZ782sE2uu rdj6oX7nANu0hoQ+IdTkS3pEBv8hc3qOgnPk4vz1OBMwhS2lqQMWbLPNeRcBnhGaXwbItm9az lZ3od/TISJz0BYWNT4jyBykUodrY8TmhGM8ol9/l4enbhRvAwZ3z1fPkxWbqtJSayOgyKrb9F PkxBdVWZd4drg2ZDv7oKf70dWxE6reCO0dvFVyz+sLQ9ew4kJJHco3m2j8rnSI+QUdVcHeDfj mHtJmaDlIytpyoOFfHyJOHX0lodzcmN8pxozzS3Mo1sRZZWfMxVh9qpbUJpmoKFwCfXKoGmSB HcVKI0mCuyq8BliCXfLtLLCe6tVloGvXb61zOMQHqm5VDacnE5xo3Zz4smjQJDlKqeSTHc/AK i2wbINVYkoBNimKf1 Received-SPF: pass client-ip=212.227.15.18; envelope-from=deller@gmx.de; helo=mout.gmx.net X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/04 09:08:36 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Spam_score_int: -35 X-Spam_score: -3.6 X-Spam_bar: --- X-Spam_report: (-3.6 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Helge Deller , =?utf-8?q?Philippe_Mathieu-Daud=C3=A9?= , Richard Henderson Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" From: Philippe Mathieu-Daudé Invalid I/O writes can craft an offset out of the vram_buffer range. Instead of passing an unsafe pointer to artist_rop8(), pass the vram_buffer and the offset. We can now check if the offset is in range before accessing it. We avoid: Program terminated with signal SIGSEGV, Segmentation fault. 284 *dst &= ~plane_mask; (gdb) bt #0 0x000056367b2085c0 in artist_rop8 (s=0x56367d38b510, dst=0x7f9f972fffff , val=0 '\000') at hw/display/artist.c:284 #1 0x000056367b209325 in draw_line (s=0x56367d38b510, x1=-20480, y1=-1, x2=0, y2=17920, update_start=true, skip_pix=-1, max_pix=-1) at hw/display/artist.c:646 Reported-by: LLVM libFuzzer Buglink: https://bugs.launchpad.net/qemu/+bug/1880326 Signed-off-by: Philippe Mathieu-Daudé Signed-off-by: Helge Deller Reported-by: LLVM libFuzzer Reported-by: Alexander Bulekov Signed-off-by: Helge Deller Reported-by: LLVM libFuzzer Reported-by: Alexander Bulekov Signed-off-by: Helge Deller Reported-by: LLVM libFuzzer Reported-by: Alexander Bulekov Acked-by: Alexander Bulekov Signed-off-by: Helge Deller Acked-by: Alexander Bulekov --- hw/display/artist.c | 40 +++++++++++++++++++++++++--------------- 1 file changed, 25 insertions(+), 15 deletions(-) -- 2.21.3 diff --git a/hw/display/artist.c b/hw/display/artist.c index a206afe641..47de17b9e9 100644 --- a/hw/display/artist.c +++ b/hw/display/artist.c @@ -273,11 +273,20 @@ static artist_rop_t artist_get_op(ARTISTState *s) return (s->image_bitmap_op >> 8) & 0xf; } -static void artist_rop8(ARTISTState *s, uint8_t *dst, uint8_t val) +static void artist_rop8(ARTISTState *s, struct vram_buffer *buf, + int offset, uint8_t val) { - const artist_rop_t op = artist_get_op(s); - uint8_t plane_mask = s->plane_mask & 0xff; + uint8_t plane_mask; + uint8_t *dst; + + if (offset < 0 || offset >= buf->size) { + qemu_log_mask(LOG_GUEST_ERROR, + "rop8 offset:%d bufsize:%u\n", offset, buf->size); + return; + } + dst = buf->data + offset; + plane_mask = s->plane_mask & 0xff; switch (op) { case ARTIST_ROP_CLEAR: @@ -375,7 +384,7 @@ static void vram_bit_write(ARTISTState *s, int posx, int posy, bool incr_x, for (i = 0; i < pix_count; i++) { uint32_t off = offset + pix_count - 1 - i; if (off < buf->size) { - artist_rop8(s, p + off, + artist_rop8(s, buf, off, (data & 1) ? (s->plane_mask >> 24) : 0); } data >>= 1; @@ -395,7 +404,7 @@ static void vram_bit_write(ARTISTState *s, int posx, int posy, bool incr_x, s->vram_bitmask & (1 << (28 + i))) { uint32_t off = offset + 3 - i; if (off < buf->size) { - artist_rop8(s, p + off, data8[ROP8OFF(i)]); + artist_rop8(s, buf, off, data8[ROP8OFF(i)]); } } } @@ -424,10 +433,10 @@ static void vram_bit_write(ARTISTState *s, int posx, int posy, bool incr_x, if (!(s->image_bitmap_op & 0x20000000) || (vram_bitmask & mask)) { if (data & mask) { - artist_rop8(s, p + offset + i, s->fg_color); + artist_rop8(s, buf, offset + i, s->fg_color); } else { if (!(s->image_bitmap_op & 0x10000002)) { - artist_rop8(s, p + offset + i, s->bg_color); + artist_rop8(s, buf, offset + i, s->bg_color); } } } @@ -505,7 +514,7 @@ static void block_move(ARTISTState *s, int source_x, int source_y, int dest_x, if (dst + column > buf->size || src + column > buf->size) { continue; } - artist_rop8(s, buf->data + dst + column, buf->data[src + column]); + artist_rop8(s, buf, dst + column, buf->data[src + column]); } } @@ -546,7 +555,7 @@ static void fill_window(ARTISTState *s, int startx, int starty, offset = y * s->width; for (x = startx; x < startx + width; x++) { - artist_rop8(s, buf->data + offset + x, color); + artist_rop8(s, buf, offset + x, color); } } artist_invalidate_lines(buf, starty, height); @@ -559,7 +568,6 @@ static void draw_line(ARTISTState *s, int x1, int y1, int x2, int y2, uint8_t color; int dx, dy, t, e, x, y, incy, diago, horiz; bool c1; - uint8_t *p; trace_artist_draw_line(x1, y1, x2, y2); @@ -628,16 +636,18 @@ static void draw_line(ARTISTState *s, int x1, int y1, int x2, int y2, color = artist_get_color(s); do { + int ofs; + if (c1) { - p = buf->data + x * s->width + y; + ofs = x * s->width + y; } else { - p = buf->data + y * s->width + x; + ofs = y * s->width + x; } if (skip_pix > 0) { skip_pix--; } else { - artist_rop8(s, p, color); + artist_rop8(s, buf, ofs, color); } if (e > 0) { @@ -771,10 +781,10 @@ static void font_write16(ARTISTState *s, uint16_t val) for (i = 0; i < 16; i++) { mask = 1 << (15 - i); if (val & mask) { - artist_rop8(s, buf->data + offset + i, color); + artist_rop8(s, buf, offset + i, color); } else { if (!(s->image_bitmap_op & 0x20000000)) { - artist_rop8(s, buf->data + offset + i, s->bg_color); + artist_rop8(s, buf, offset + i, s->bg_color); } } }