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[88.21.202.17]) by smtp.gmail.com with ESMTPSA id 7sm16470119wra.50.2020.05.18.03.31.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 May 2020 03:31:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=/8KpyGeYnxwgdK2inDnegDN6dVAbbEOMHxx/mPBVFCM=; b=qWdFVj7LBsQZJv3ZYG8gYyWZiwTvpDZ0N5sxPn5kD4Ym2A6QLfB/zput22BjfuSONP fMa2xKiryLFsDg1tj4OnVhAx/QTXVcZYovajYN6eoQEeMt7bXN1vAQtYwfpal7gAcfB3 sxrn43JcfMI8DHVt7uUX0MMk9ysmfc5xrWws9k6PznMnatRV4n1IGn1FqTga4UFUtOpO ribwR++YIJQOKiHzmfnikVRvu80QLF/EHuAhHoSmEmJjqSX9X+jKs/6pYuGyy5SnJ++T 2ry+gPQhrOcyj440VVOY2x3g8M23a/MqLYdV1ZjMl+KJjua6nuM3aM0ASjNchbPwJOwE tAkw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :mime-version:content-transfer-encoding; bh=/8KpyGeYnxwgdK2inDnegDN6dVAbbEOMHxx/mPBVFCM=; b=I6ddRL97J+WuIkBDlncRpDUkYGZTv6U/TWC1hLG56iNa/SbV/TvyIcyJr0sZe/H/oO 5EPAvlUU55HjtvdcH9EDA5xAaYGSivJxpy+YAWH0rhYjZlbiwDUnNeAw35TB6yzktcwE 1YX5PFusq1185qyGX7+YYSykiHi0LcmvWV8iHrgmzseOHWetUN43Xfg9OcgalUATuBdH xdka/qb0DKrWK9o/IPn26qd8w/v3N/KBbIaXYKpUO9Otdvj6Gs84z7zsUO9+SS3mEy5G aqVvyxkxyoxdqHKSeDH2s2fXN+DbFtjis+mEpuS+o/4Dsl47fdXgR8A7AlEtuvalL0x7 mxbw== X-Gm-Message-State: AOAM533E+vMos+s81ALbZdJwNtlg8aphM05YZUzBWBg3yG0AwEBNm2wY kzcE/e4oJDCyyme2TDC0uE4gBS0PxBY= X-Google-Smtp-Source: ABdhPJwfP+g4U25zIoHlgAaeT+fcrbUvJ0POM2mIxwCHnMvcRbTg/Tc/Aqmu2CQY0jRUmSfUhb+m4A== X-Received: by 2002:a1c:b604:: with SMTP id g4mr18632697wmf.103.1589797875257; Mon, 18 May 2020 03:31:15 -0700 (PDT) From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= To: qemu-devel@nongnu.org Subject: [RFC PATCH v2] hw/i386/vmport: Allow QTest use without crashing Date: Mon, 18 May 2020 12:31:13 +0200 Message-Id: <20200518103113.9882-1-f4bug@amsat.org> X-Mailer: git-send-email 2.21.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::343; envelope-from=philippe.mathieu.daude@gmail.com; helo=mail-wm1-x343.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. X-Spam_score_int: -16 X-Spam_score: -1.7 X-Spam_bar: - X-Spam_report: (-1.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FORGED_FROMDOMAIN=0.001, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.249, RCVD_IN_DNSWL_NONE=-0.0001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=_AUTOLEARN 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: Eduardo Habkost , "Michael S. Tsirkin" , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Alexander Bulekov , Paolo Bonzini , Richard Henderson Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Trying libFuzzer on the vmport device, we get: AddressSanitizer:DEADLYSIGNAL =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =3D=3D29476=3D=3DERROR: AddressSanitizer: SEGV on unknown address 0x00000= 0008840 (pc 0x56448bec4d79 bp 0x7ffeec9741b0 sp 0x7ffeec9740e0 T0) =3D=3D29476=3D=3DThe signal is caused by a READ memory access. #0 0x56448bec4d78 in vmport_ioport_read (qemu-fuzz-i386+0x1260d78) #1 0x56448bb5f175 in memory_region_read_accessor (qemu-fuzz-i386+0xefb1= 75) #2 0x56448bb30c13 in access_with_adjusted_size (qemu-fuzz-i386+0xeccc13) #3 0x56448bb2ea27 in memory_region_dispatch_read1 (qemu-fuzz-i386+0xeca= a27) #4 0x56448bb2e443 in memory_region_dispatch_read (qemu-fuzz-i386+0xeca4= 43) #5 0x56448b961ab1 in flatview_read_continue (qemu-fuzz-i386+0xcfdab1) #6 0x56448b96336d in flatview_read (qemu-fuzz-i386+0xcff36d) #7 0x56448b962ec4 in address_space_read_full (qemu-fuzz-i386+0xcfeec4) This is easily reproducible using: $ echo inb 0x5658 | qemu-system-i386 -M isapc,accel=3Dqtest -qtest stdio [I 1589796572.009763] OPENED [R +0.008069] inb 0x5658 Segmentation fault (core dumped) $ coredumpctl gdb -q Program terminated with signal SIGSEGV, Segmentation fault. #0 0x00005605b54d0f21 in vmport_ioport_read (opaque=3D0x5605b7531ce0, ad= dr=3D0, size=3D4) at hw/i386/vmport.c:77 77 eax =3D env->regs[R_EAX]; (gdb) p cpu $1 =3D (X86CPU *) 0x0 (gdb) bt #0 0x00005605b54d0f21 in vmport_ioport_read (opaque=3D0x5605b7531ce0, ad= dr=3D0, size=3D4) at hw/i386/vmport.c:77 #1 0x00005605b53db114 in memory_region_read_accessor (mr=3D0x5605b7531d8= 0, addr=3D0, value=3D0x7ffc9d261a30, size=3D4, shift=3D0, mask=3D4294967295= , attrs=3D...) at memory.c:434 #2 0x00005605b53db5d4 in access_with_adjusted_size (addr=3D0, value=3D0x= 7ffc9d261a30, size=3D1, access_size_min=3D4, access_size_max=3D4, access_fn= =3D 0x5605b53db0d2 , mr=3D0x5605b7531d80, at= trs=3D...) at memory.c:544 #3 0x00005605b53de156 in memory_region_dispatch_read1 (mr=3D0x5605b7531d= 80, addr=3D0, pval=3D0x7ffc9d261a30, size=3D1, attrs=3D...) at memory.c:1396 #4 0x00005605b53de228 in memory_region_dispatch_read (mr=3D0x5605b7531d8= 0, addr=3D0, pval=3D0x7ffc9d261a30, op=3DMO_8, attrs=3D...) at memory.c:1424 #5 0x00005605b537c80a in flatview_read_continue (fv=3D0x5605b7650290, ad= dr=3D22104, attrs=3D..., ptr=3D0x7ffc9d261b4b, len=3D1, addr1=3D0, l=3D1, m= r=3D0x5605b7531d80) at exec.c:3200 #6 0x00005605b537c95d in flatview_read (fv=3D0x5605b7650290, addr=3D2210= 4, attrs=3D..., buf=3D0x7ffc9d261b4b, len=3D1) at exec.c:3239 #7 0x00005605b537c9e6 in address_space_read_full (as=3D0x5605b5f74ac0 , addr=3D22104, attrs=3D..., buf=3D0x7ffc9d261b4b, len=3D1)= at exec.c:3252 #8 0x00005605b53d5a5d in address_space_read (len=3D1, buf=3D0x7ffc9d261b= 4b, attrs=3D..., addr=3D22104, as=3D0x5605b5f74ac0 ) at i= nclude/exec/memory.h:2401 #9 0x00005605b53d5a5d in cpu_inb (addr=3D22104) at ioport.c:88 X86CPU is NULL because QTest accelerator does not use CPU. Fix by returning default values when QTest accelerator is used. Reported-by: Clang AddressSanitizer Signed-off-by: Philippe Mathieu-Daud=C3=A9 --- v2: Removed Red Hat authorship =C2=AF\_(=E3=83=84)_/=C2=AF hw/i386/vmport.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/hw/i386/vmport.c b/hw/i386/vmport.c index 1aaaab691a..4ec95f8778 100644 --- a/hw/i386/vmport.c +++ b/hw/i386/vmport.c @@ -24,6 +24,7 @@ #include "qemu/osdep.h" #include "hw/isa/isa.h" #include "sysemu/hw_accel.h" +#include "sysemu/qtest.h" #include "qemu/log.h" #include "vmport.h" #include "cpu.h" @@ -64,10 +65,14 @@ static uint64_t vmport_ioport_read(void *opaque, hwaddr= addr, VMPortState *s =3D opaque; CPUState *cs =3D current_cpu; X86CPU *cpu =3D X86_CPU(cs); - CPUX86State *env =3D &cpu->env; + CPUX86State *env; unsigned char command; uint32_t eax; =20 + if (qtest_enabled()) { + return -1; + } + env =3D &cpu->env; cpu_synchronize_state(cs); =20 eax =3D env->regs[R_EAX]; @@ -90,6 +95,9 @@ static void vmport_ioport_write(void *opaque, hwaddr addr, { X86CPU *cpu =3D X86_CPU(current_cpu); =20 + if (qtest_enabled()) { + return; + } cpu->env.regs[R_EAX] =3D vmport_ioport_read(opaque, addr, 4); } =20 @@ -97,6 +105,9 @@ static uint32_t vmport_cmd_get_version(void *opaque, uin= t32_t addr) { X86CPU *cpu =3D X86_CPU(current_cpu); =20 + if (qtest_enabled()) { + return -1; + } cpu->env.regs[R_EBX] =3D VMPORT_MAGIC; return 6; } @@ -105,6 +116,9 @@ static uint32_t vmport_cmd_ram_size(void *opaque, uint3= 2_t addr) { X86CPU *cpu =3D X86_CPU(current_cpu); =20 + if (qtest_enabled()) { + return -1; + } cpu->env.regs[R_EBX] =3D 0x1177; return ram_size; } --=20 2.21.3