From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35253) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eWOdU-0003Sl-Az for qemu-devel@nongnu.org; Tue, 02 Jan 2018 10:37:53 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eWOdR-0001wx-Mv for qemu-devel@nongnu.org; Tue, 02 Jan 2018 10:37:52 -0500 From: Thomas Huth Date: Tue, 2 Jan 2018 16:37:45 +0100 Message-Id: <1514907465-14530-1-git-send-email-thuth@redhat.com> Subject: [Qemu-devel] [PATCH] crypto/ivgen-essiv: Fix problem with address sanitizer of Clang List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org, "Daniel P. Berrange" Cc: qemu-trivial@nongnu.org When compiling QEMU with clang and -fsanitize=address, I get the following error: ==9185==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7ffc7e9adf2f at pc 0x564cba001d88 bp 0x7ffc7e9adeb0 sp 0x7ffc7e9adea8 READ of size 16 at 0x7ffc7e9adf2f thread T0 #0 0x564cba001d87 in qcrypto_ivgen_essiv_calculate .../crypto/ivgen-essiv.c:83 #1 0x564cba001367 in qcrypto_ivgen_calculate .../crypto/ivgen.c:72 #2 0x564cb9fec630 in test_ivgen .../tests/test-crypto-ivgen.c:148 #3 0x7f98f4224b39 (/lib64/libglib-2.0.so.0+0x6fb39) #4 0x7f98f4224d02 (/lib64/libglib-2.0.so.0+0x6fd02) #5 0x7f98f4224d02 (/lib64/libglib-2.0.so.0+0x6fd02) #6 0x7f98f4224d02 (/lib64/libglib-2.0.so.0+0x6fd02) #7 0x7f98f4224f0d (/lib64/libglib-2.0.so.0+0x6ff0d) #8 0x7f98f4224f30 (/lib64/libglib-2.0.so.0+0x6ff30) #9 0x564cb9fec446 in main .../tests/test-crypto-ivgen.c:173 #10 0x7f98f294fc04 in __libc_start_main (/lib64/libc.so.6+0x21c04) #11 0x564cb9fec1ac in _start (.../tests/test-crypto-ivgen+0xdb1ac) Address 0x7ffc7e9adf2f is located in stack of thread T0 at offset 47 in frame #0 0x564cba00192f in qcrypto_ivgen_essiv_calculate .../crypto/ivgen-essiv.c:76 And indeed, the code is doing a "memcpy(data, (uint8_t *)§or, ndata)" here with "sector" being a uint64_t variable and ndata = 16. Fix it by limiting the size of the memcpy correctly. Signed-off-by: Thomas Huth --- crypto/ivgen-essiv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/crypto/ivgen-essiv.c b/crypto/ivgen-essiv.c index cba20bd..8944609 100644 --- a/crypto/ivgen-essiv.c +++ b/crypto/ivgen-essiv.c @@ -79,7 +79,7 @@ static int qcrypto_ivgen_essiv_calculate(QCryptoIVGen *ivgen, uint8_t *data = g_new(uint8_t, ndata); sector = cpu_to_le64(sector); - memcpy(data, (uint8_t *)§or, ndata); + memcpy(data, (uint8_t *)§or, MIN(ndata, sizeof(sector))); if (sizeof(sector) < ndata) { memset(data + sizeof(sector), 0, ndata - sizeof(sector)); } -- 1.8.3.1