| Message ID | 20200413220100.18628-1-f4bug@amsat.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [PATCH-for-5.0,v2] hw/display/sm501: Avoid heap overflow in sm501_2d_operation() | expand |
diff --git a/hw/display/sm501.c b/hw/display/sm501.c index de0ab9d977..902acb3875 100644 --- a/hw/display/sm501.c +++ b/hw/display/sm501.c @@ -726,6 +726,12 @@ static void sm501_2d_operation(SM501State *s) int crt = (s->dc_crt_control & SM501_DC_CRT_CONTROL_SEL) ? 1 : 0; int fb_len = get_width(s, crt) * get_height(s, crt) * get_bpp(s, crt); + if (rtl && (src_x < operation_width || src_y < operation_height)) { + qemu_log_mask(LOG_GUEST_ERROR, "sm501: Illegal RTL address (%i, %i)\n", + src_x, src_y); + return; + } + if (addressing != 0x0) { printf("%s: only XY addressing is supported.\n", __func__); abort();
Zhang Zi Ming reported a heap overflow in the Drawing Engine of the SM501 companion chip model, in particular in the COPY_AREA() macro in sm501_2d_operation(). Add a simple check to avoid the heap overflow. This fixes: ================================================================= ==20518==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7f6f4c3fffff at pc 0x55b1e1d358f0 bp 0x7ffce464dfb0 sp 0x7ffce464dfa8 READ of size 1 at 0x7f6f4c3fffff thread T0 #0 0x55b1e1d358ef in sm501_2d_operation hw/display/sm501.c:788:13 #1 0x55b1e1d32c38 in sm501_2d_engine_write hw/display/sm501.c:1466:13 #2 0x55b1e0cd19d8 in memory_region_write_accessor memory.c:483:5 #3 0x55b1e0cd1404 in access_with_adjusted_size memory.c:544:18 #4 0x55b1e0ccfb9d in memory_region_dispatch_write memory.c:1476:16 #5 0x55b1e0ae55a8 in flatview_write_continue exec.c:3125:23 #6 0x55b1e0ad3e87 in flatview_write exec.c:3165:14 #7 0x55b1e0ad3a24 in address_space_write exec.c:3256:18 0x7f6f4c3fffff is located 4194303 bytes to the right of 4194304-byte region [0x7f6f4bc00000,0x7f6f4c000000) allocated by thread T0 here: #0 0x55b1e0a6e715 in __interceptor_posix_memalign (ppc64-softmmu/qemu-system-ppc64+0x19c0715) #1 0x55b1e31c1482 in qemu_try_memalign util/oslib-posix.c:189:11 #2 0x55b1e31c168c in qemu_memalign util/oslib-posix.c:205:27 #3 0x55b1e11a00b3 in spapr_reallocate_hpt hw/ppc/spapr.c:1560:23 #4 0x55b1e11a0ce4 in spapr_setup_hpt hw/ppc/spapr.c:1593:5 #5 0x55b1e11c2fba in spapr_machine_reset hw/ppc/spapr.c:1644:9 #6 0x55b1e1368b01 in qemu_system_reset softmmu/vl.c:1391:9 #7 0x55b1e1375af3 in qemu_init softmmu/vl.c:4436:5 #8 0x55b1e2fc8a59 in main softmmu/main.c:48:5 #9 0x7f6f8150bf42 in __libc_start_main (/lib64/libc.so.6+0x23f42) SUMMARY: AddressSanitizer: heap-buffer-overflow hw/display/sm501.c:788:13 in sm501_2d_operation Shadow bytes around the buggy address: 0x0fee69877fa0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0fee69877fb0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0fee69877fc0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0fee69877fd0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0fee69877fe0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa =>0x0fee69877ff0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa[fa] 0x0fee69878000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0fee69878010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0fee69878020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0fee69878030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 0x0fee69878040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Poisoned by user: f7 ASan internal: fe ==20518==ABORTING Cc: qemu-stable@nongnu.org Fixes: 07d8a50cb0e ("sm501: add 2D engine copyrect support") Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=1786026 Reported-by: Zhang Zi Ming <1015138407@qq.com> Acked-by: BALATON Zoltan <balaton@eik.bme.hu> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org> --- Since v1: Reword description & add Zoltan's A-b. Test to verify this bug: https://www.mail-archive.com/qemu-devel@nongnu.org/msg695421.html Per the links on https://bugzilla.redhat.com/show_bug.cgi?id=1808510 there is probably a CVE assigned to this, but I don't have access to the information, https://bugzilla.redhat.com/show_bug.cgi?id=1786593 only show: You are not authorized to access bug #1786593. Most likely the bug has been restricted for internal development processes and we cannot grant access. Anyway as this code is not used in conjunction with a hypervisor, it is not a 'security bug' as described in https://www.qemu.org/contribute/security-process/ and https://www.qemu.org/docs/master/system/security.html#non-virtualization-use-case --- hw/display/sm501.c | 6 ++++++ 1 file changed, 6 insertions(+)