From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43857) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ej8ig-0005Ba-3t for qemu-devel@nongnu.org; Tue, 06 Feb 2018 14:15:59 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ej8ic-0007us-Mx for qemu-devel@nongnu.org; Tue, 06 Feb 2018 14:15:54 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:57382) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ej8ic-0007uL-F8 for qemu-devel@nongnu.org; Tue, 06 Feb 2018 14:15:50 -0500 Received: from pps.filterd (m0098393.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id w16JFBDU139261 for ; Tue, 6 Feb 2018 14:15:49 -0500 Received: from e17.ny.us.ibm.com (e17.ny.us.ibm.com [129.33.205.207]) by mx0a-001b2d01.pphosted.com with ESMTP id 2fyha5u360-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Tue, 06 Feb 2018 14:15:48 -0500 Received: from localhost by e17.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 6 Feb 2018 14:15:47 -0500 From: Michael Roth Date: Tue, 6 Feb 2018 13:14:41 -0600 In-Reply-To: <20180206191515.25830-1-mdroth@linux.vnet.ibm.com> References: <20180206191515.25830-1-mdroth@linux.vnet.ibm.com> Message-Id: <20180206191515.25830-21-mdroth@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH 20/54] i386: Change X86CPUDefinition::model_id to const char* List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, christian.ehrhardt@canonical.com, Eduardo Habkost From: Eduardo Habkost It is valid to have a 48-character model ID on CPUID, however the definition of X86CPUDefinition::model_id is char[48], which can make the compiler drop the null terminator from the string. If a CPU model happens to have 48 bytes on model_id, "-cpu help" will print garbage and the object_property_set_str() call at x86_cpu_load_def() will read data outside the model_id array. We could increase the array size to 49, but this would mean the compiler would not issue a warning if a 49-char string is used by mistake for model_id. To make things simpler, simply change model_id to be const char*, and validate the string length using an assert() on x86_register_cpudef_type(). Reported-by: "Dr. David Alan Gilbert" Signed-off-by: Eduardo Habkost Message-Id: <20180109154519.25634-2-ehabkost@redhat.com> Signed-off-by: Eduardo Habkost (cherry picked from commit 807e9869b8c4119b81df902625af818519e01759) Signed-off-by: Michael Roth --- target/i386/cpu.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/target/i386/cpu.c b/target/i386/cpu.c index 045d66191f..63279526a1 100644 --- a/target/i386/cpu.c +++ b/target/i386/cpu.c @@ -748,7 +748,7 @@ struct X86CPUDefinition { int model; int stepping; FeatureWordArray features; - char model_id[48]; + const char *model_id; }; static X86CPUDefinition builtin_x86_defs[] = { @@ -917,6 +917,7 @@ static X86CPUDefinition builtin_x86_defs[] = { .features[FEAT_1_EDX] = I486_FEATURES, .xlevel = 0, + .model_id = "", }, { .name = "pentium", @@ -928,6 +929,7 @@ static X86CPUDefinition builtin_x86_defs[] = { .features[FEAT_1_EDX] = PENTIUM_FEATURES, .xlevel = 0, + .model_id = "", }, { .name = "pentium2", @@ -939,6 +941,7 @@ static X86CPUDefinition builtin_x86_defs[] = { .features[FEAT_1_EDX] = PENTIUM2_FEATURES, .xlevel = 0, + .model_id = "", }, { .name = "pentium3", @@ -950,6 +953,7 @@ static X86CPUDefinition builtin_x86_defs[] = { .features[FEAT_1_EDX] = PENTIUM3_FEATURES, .xlevel = 0, + .model_id = "", }, { .name = "athlon", @@ -2708,6 +2712,9 @@ static void x86_register_cpudef_type(X86CPUDefinition *def) * they shouldn't be set on the CPU model table. */ assert(!(def->features[FEAT_8000_0001_EDX] & CPUID_EXT2_AMD_ALIASES)); + /* catch mistakes instead of silently truncating model_id when too long */ + assert(def->model_id && strlen(def->model_id) <= 48); + type_register(&ti); g_free(typename); -- 2.11.0