{"id":2230512,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2230512/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260429193007.1670335-1-stefanb@linux.ibm.com/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/1.1/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260429193007.1670335-1-stefanb@linux.ibm.com>","date":"2026-04-29T19:30:07","name":"tpm_emulator: Limit number of bytes read from buffer to size of buffer","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"218d891d7054d1a3a2cf49dbb54cf50b8ccf14a7","submitter":{"id":75097,"url":"http://patchwork.ozlabs.org/api/1.1/people/75097/?format=json","name":"Stefan Berger","email":"stefanb@linux.ibm.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260429193007.1670335-1-stefanb@linux.ibm.com/mbox/","series":[{"id":502141,"url":"http://patchwork.ozlabs.org/api/1.1/series/502141/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=502141","date":"2026-04-29T19:30:07","name":"tpm_emulator: Limit number of bytes read from buffer to size of buffer","version":1,"mbox":"http://patchwork.ozlabs.org/series/502141/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2230512/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2230512/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=ibm.com header.i=@ibm.com header.a=rsa-sha256\n header.s=pp1 header.b=HW+ZYvjP;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=cc\n :content-transfer-encoding:date:from:message-id:mime-version\n :subject:to; s=pp1; bh=CJmcDM5jgEjnPXBxj/7Ca1M+T8PXMWrF8WtKlxycV\n jc=; b=HW+ZYvjPpDlK63F34OmY4wQYONXF8kq6A04pIcnaR2rLsGOg/KYOlZvuG\n 8d8LVMu6rzuFBSxVwvCF4bBnQkHq8H//us6rgbDWjKRp4DkAqE396kd/sKE15LfD\n u/sXRV9eIxQ0p/X1u583nE7kaM1ZsxhtwMpMHwMXkanLpqoPxzTTLN8kPvkbkH4r\n 2BS4fdJVm9lQZvqL1OJ8NpK3PgnSpxNjGjvLLgK15XjmpeaIbvkYYQi9FjJISJVz\n 6c9wg28yQK+/aeHpgG64Z0OEB1uGOKBY/3g7juBAX67Tu++rvYXoxF9vb58Enjxq\n OGdFlUjh58VIAeKM1OmBqaxBu8uQQ==","From":"Stefan Berger ","To":"qemu-devel@nongnu.org","Cc":"marcandre.lureau@redhat.com, armenon@redhat.com,\n Stefan Berger ","Subject":"[PATCH] tpm_emulator: Limit number of bytes read from buffer to size\n of buffer","Date":"Wed, 29 Apr 2026 19:30:07 +0000","Message-ID":"<20260429193007.1670335-1-stefanb@linux.ibm.com>","X-Mailer":"git-send-email 2.43.0","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","X-TM-AS-GCONF":"00","X-Proofpoint-ORIG-GUID":"5M9hyLQxeb7H9T8Y75BzgIU4u0kRvJan","X-Proofpoint-Spam-Details-Enc":"AW1haW4tMjYwNDI5MDE5MyBTYWx0ZWRfX9bHnoH5FtlDK\n ZCPJgCmON8rWAANfi7mp3Dxig4Weg9vCd61CLwSvaraxcwvLIzAYzZYvO0nDgAiRq9pBfu8A0cA\n thKgPjktdwbWQAWvTujWVs+AUiO+txsre/ClIC5dVi9rNresaZ0LL8LdTtd4IDPFyv8vcve0XGE\n AITMT4u99D7XEtoIcmH1Xlr48qa2gXDOPQyW0DyjpBmbU5EoNl1M4eMqZC/vHg8a0zGaAqU9Q+u\n eCOY/U9qHS4bbst7bjfvraYrmn1ekCCiKvBt3JYV45e5K2HkZGrJf5cEKTzawxAXCasADvxbVGX\n VmM9/LPn2XIfm92nX9AEP61/F0XFE/6qtSGUYWp0JtAEdioNvfm7cbpP5LBcJAfJVCnFsH1ckvx\n JMLEc0adNyKlFkdLm3nQHJzaEx6ptaDqSTOqXPCURUjWBFPxpyrGETIq3wR4PInSDsBfxSM+0qT\n U20Uwc4xyDaES4jDt2Q==","X-Authority-Analysis":"v=2.4 cv=VZLH+lp9 c=1 sm=1 tr=0 ts=69f25c48 cx=c_pps\n a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17\n a=RUyTQ2W-OykcHckI:21 a=A5OVakUREuEA:10 a=VkNPw1HP01LnGYTKEx00:22\n a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8\n a=89LiysFeuzQG30zlTEIA:9","X-Proofpoint-GUID":"5M9hyLQxeb7H9T8Y75BzgIU4u0kRvJan","X-Proofpoint-Virus-Version":"vendor=baseguard\n engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49\n definitions=2026-04-29_02,2026-04-28_01,2025-10-01_01","X-Proofpoint-Spam-Details":"rule=outbound_notspam policy=outbound score=0\n clxscore=1015 suspectscore=0 adultscore=0 lowpriorityscore=0 phishscore=0\n spamscore=0 malwarescore=0 bulkscore=0 priorityscore=1501 impostorscore=0\n classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0\n reason=mlx scancount=1 engine=8.22.0-2604200000 definitions=main-2604290193","Received-SPF":"pass client-ip=148.163.158.5;\n envelope-from=stefanb@linux.ibm.com;\n helo=mx0b-001b2d01.pphosted.com","X-Spam_score_int":"-26","X-Spam_score":"-2.7","X-Spam_bar":"--","X-Spam_report":"(-2.7 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7,\n RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001,\n SPF_PASS=-0.001 autolearn=ham autolearn_force=no","X-Spam_action":"no action","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.29","Precedence":"list","List-Id":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"Limit the number of bytes read from the TPM response to the size of the\nreceiving buffer and drain the other bytes from the response by reading\nthem into a temporary buffer.\n\nThe size of the TPM's responses should fit into a buffer negotiated with\nthe tpm_emulator (swtpm). However, it is better to proactively limit the\nnumber of bytes read into the buffer by using the buffer's size as an\nupper limit.\n\nSigned-off-by: Stefan Berger \n---\n backends/tpm/tpm_emulator.c | 23 ++++++++++++++++++++---\n 1 file changed, 20 insertions(+), 3 deletions(-)","diff":"diff --git a/backends/tpm/tpm_emulator.c b/backends/tpm/tpm_emulator.c\nindex 75c33d290e..5e8bad1632 100644\n--- a/backends/tpm/tpm_emulator.c\n+++ b/backends/tpm/tpm_emulator.c\n@@ -176,8 +176,11 @@ static int tpm_emulator_unix_tx_bufs(TPMEmulator *tpm_emu,\n bool *selftest_done,\n Error **errp)\n {\n- ssize_t ret;\n bool is_selftest = false;\n+ uint8_t buffer[1024];\n+ size_t to_drain = 0;\n+ size_t to_read;\n+ ssize_t ret;\n \n if (selftest_done) {\n *selftest_done = false;\n@@ -195,13 +198,27 @@ static int tpm_emulator_unix_tx_bufs(TPMEmulator *tpm_emu,\n return -1;\n }\n \n+ to_read = tpm_cmd_get_size(out) - sizeof(struct tpm_resp_hdr);\n+ if (to_read > out_len) {\n+ to_drain = to_read - out_len;\n+ to_read = out_len;\n+ }\n+\n ret = qio_channel_read_all(tpm_emu->data_ioc,\n- (char *)out + sizeof(struct tpm_resp_hdr),\n- tpm_cmd_get_size(out) - sizeof(struct tpm_resp_hdr), errp);\n+ (char *)out + sizeof(struct tpm_resp_hdr), to_read, errp);\n if (ret != 0) {\n return -1;\n }\n \n+ while (to_drain) {\n+ to_read = MIN(to_drain, sizeof(buffer));\n+ ret = qio_channel_read_all(tpm_emu->data_ioc, buffer, to_read, errp);\n+ if (ret != 0) {\n+ return -1;\n+ }\n+ to_drain -= to_read;\n+ }\n+\n if (is_selftest) {\n *selftest_done = tpm_cmd_get_errcode(out) == 0;\n }\n","prefixes":[]}