Matheus Tavares Bernardino <quic_mathb...@quicinc.com> wrote: > xbzrle_encode_buffer_avx512() checks for overflows too scarcely in its > outer loop, causing out-of-bounds writes: > > $ ../configure --target-list=aarch64-softmmu --enable-sanitizers > --enable-avx512bw > $ make tests/unit/test-xbzrle && ./tests/unit/test-xbzrle > > ==5518==ERROR: AddressSanitizer: heap-buffer-overflow on address > 0x62100000b100 at pc 0x561109a7714d bp 0x7ffed712a440 sp 0x7ffed712a430 > WRITE of size 1 at 0x62100000b100 thread T0 > #0 0x561109a7714c in uleb128_encode_small ../util/cutils.c:831 > #1 0x561109b67f6a in xbzrle_encode_buffer_avx512 ../migration/xbzrle.c:275 > #2 0x5611099a7428 in test_encode_decode_overflow > ../tests/unit/test-xbzrle.c:153 > #3 0x7fb2fb65a58d (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x7a58d) > #4 0x7fb2fb65a333 (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x7a333) > #5 0x7fb2fb65aa79 in g_test_run_suite > (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x7aa79) > #6 0x7fb2fb65aa94 in g_test_run > (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x7aa94) > #7 0x5611099a3a23 in main ../tests/unit/test-xbzrle.c:218 > #8 0x7fb2fa78c082 in __libc_start_main > (/lib/x86_64-linux-gnu/libc.so.6+0x24082) > #9 0x5611099a608d in _start (/qemu/build/tests/unit/test-xbzrle+0x28408d) > > 0x62100000b100 is located 0 bytes to the right of 4096-byte region > [0x62100000a100,0x62100000b100) > allocated by thread T0 here: > #0 0x7fb2fb823a06 in __interceptor_calloc > ../../../../src/libsanitizer/asan/asan_malloc_linux.cc:153 > #1 0x7fb2fb637ef0 in g_malloc0 > (/lib/x86_64-linux-gnu/libglib-2.0.so.0+0x57ef0) > > Fix that by performing the overflow check in the inner loop, instead. > > Signed-off-by: Matheus Tavares Bernardino <quic_mathb...@quicinc.com>
Reviewed-by: Juan Quintela <quint...@redhat.com> queued. As David said, we can still improve the code. thanks, Juan.