diff options
| author | Matheus Tavares Bernardino <quic_mathbern@quicinc.com> | 2023-03-13 15:58:20 -0300 |
|---|---|---|
| committer | Juan Quintela <quintela@redhat.com> | 2023-03-16 16:07:07 +0100 |
| commit | 1776b70f55c75541e9cab3423650a59b085162a9 (patch) | |
| tree | 8bd8e0251af44b6239cb5eed2808561462e601c5 /migration/xbzrle.c | |
| parent | d84a78d15d3af9ff28ceec6906a4b101bd545b55 (diff) | |
migration/xbzrle: fix out-of-bounds write with axv512
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_mathbern@quicinc.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
Diffstat (limited to 'migration/xbzrle.c')
| -rw-r--r-- | migration/xbzrle.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/migration/xbzrle.c b/migration/xbzrle.c index 21b92d4eae..c6f8b20917 100644 --- a/migration/xbzrle.c +++ b/migration/xbzrle.c @@ -197,10 +197,6 @@ int xbzrle_encode_buffer_avx512(uint8_t *old_buf, uint8_t *new_buf, int slen, __m512i r = _mm512_set1_epi32(0); while (count512s) { - if (d + 2 > dlen) { - return -1; - } - int bytes_to_check = 64; uint64_t mask = 0xffffffffffffffff; if (count512s == 1) { @@ -216,6 +212,9 @@ int xbzrle_encode_buffer_avx512(uint8_t *old_buf, uint8_t *new_buf, int slen, bool is_same = (comp & 0x1); while (bytes_to_check) { + if (d + 2 > dlen) { + return -1; + } if (is_same) { if (nzrun_len) { d += uleb128_encode_small(dst + d, nzrun_len); |