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Tue, 4 Aug 2026 16:24:49 +0000 (GMT) From: Christian Borntraeger To: KVM Cc: Christian Borntraeger , Janosch Frank , David Hildenbrand , linux-s390 , Claudio Imbrenda , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Sven Schnelle , Matthew Rosato , Douglas Freimuth Subject: [PATCH v2 5/7] KVM: s390: Fix old_data leak in guest debug error path Date: Tue, 4 Aug 2026 18:24:33 +0200 Message-ID: <20260804162435.28617-6-borntraeger@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260804162435.28617-1-borntraeger@linux.ibm.com> References: <20260804162435.28617-1-borntraeger@linux.ibm.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=E6P9Y6dl c=1 sm=1 tr=0 ts=6a721256 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=qm1OqVo_2UFWDN3potwA:9 X-Proofpoint-ORIG-GUID: hu4N0hpDzlni7g6pZqRgg9oZturM4otP X-Proofpoint-GUID: hu4N0hpDzlni7g6pZqRgg9oZturM4otP X-Proofpoint-Spam-Info: AW1haW4tMjYwODA0MDEzMSBTYWx0ZWRfX2hdttDshLJHp H/uDQ/T5Lhgln4Yj5JqGUu7IoNKs7LXcMR72iPqqqGRwB+09AwhZydqwAZtdqdVOYfLC6a6/TNr jStd4y9G3HDhaJCLNQLlsaDNHYlehkc= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODA0MDEzMSBTYWx0ZWRfXymOvcuovFms1 y0eib75aZEmKi7sqo7sqfcZjfqkp0ARcwHX7/X/6Bb1vRK/Lc9LywDKax98b/kpvwzhQg9kJtBl 0hFvTBK0b+sOpLVTAuAZBuiDFwCpvBDD8hQG7SbkcweE8Jq1Kpk52c/3ES0Sy9cHPcvIKZ7vO34 g+vnvnYsEpTfKO4RkbVht7rnNQfx0lE1CwoWMD/oVEbuT1TDTGobaGLZxEhkc/wsJeNaulMXlnB 1bfoUDOXJYJ2og4sZVbd+nq+sSY754Qe/PpdhabY57PkctPzbdW6Ef40EM5LmUFejAO4QHIJM/g SZov/TTcYoHqHWyQX0PefH3nJEDV7hAEjKSaMw7gms+47zszOoA5m5q/xVDNjjOfbZI/YBFNwXP j2WwilXGEagUe5ZH1X1NNlLhVAMCHe1K7gHJudj8jGRqYaE7c9ms41PB6DzO8auygCo+AYKIzaI ttSNcoibdiDGvfZbdug== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-04_03,2026-08-04_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 clxscore=1015 lowpriorityscore=0 priorityscore=1501 suspectscore=0 adultscore=0 spamscore=0 malwarescore=0 impostorscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608040131 __import_wp_info() allocates a per-watchpoint old_data buffer to back up the original guest memory contents. If a later watchpoint of the same KVM_SET_GUEST_DEBUG request fails to import, kvm_s390_import_bp_data() jumps to the error label, which frees the wp_info array but not the old_data buffers of the entries that were imported successfully. Up to MAX_BP_COUNT - 1 buffers of up to MAX_WP_SIZE bytes are leaked per failed request, and the request can be repeated. Create error handling for cleaning up all created old_data memory areas. Fixes: 27291e2165b6 ("KVM: s390: hardware support for guest debugging") Cc: stable@vger.kernel.org Signed-off-by: Christian Borntraeger --- arch/s390/kvm/guestdbg.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/s390/kvm/guestdbg.c b/arch/s390/kvm/guestdbg.c index 4c02dbebb2eb..f7c94d54efbe 100644 --- a/arch/s390/kvm/guestdbg.c +++ b/arch/s390/kvm/guestdbg.c @@ -252,7 +252,7 @@ int kvm_s390_import_bp_data(struct kvm_vcpu *vcpu, ret = __import_wp_info(vcpu, &bp_data[i], &wp_info[nr_wp]); if (ret) - goto error; + goto error_wp; nr_wp++; break; case KVM_HW_BP: @@ -269,6 +269,10 @@ int kvm_s390_import_bp_data(struct kvm_vcpu *vcpu, vcpu->arch.guestdbg.hw_wp_info = wp_info; kfree(bp_data); return 0; + +error_wp: + while (nr_wp--) + kfree(wp_info[nr_wp].old_data); error: kfree(bp_data); kfree(wp_info); -- 2.53.0