From d66ae008007853df7d3a24bd2d5e7494f53f007c Mon Sep 17 00:00:00 2001 From: Greg Kurz Date: Thu, 7 Jan 2021 10:10:20 -0500 Subject: spapr: Fix buffer overflow in spapr_numa_associativity_init() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit RH-Author: Greg Kurz Message-id: <20210107101020.579456-2-gkurz@redhat.com> Patchwork-id: 100515 O-Subject: [RHEL-AV-8.4.0 qemu-kvm PATCH 1/1] spapr: Fix buffer overflow in spapr_numa_associativity_init() Bugzilla: 1908693 RH-Acked-by: David Gibson RH-Acked-by: Philippe Mathieu-Daudé RH-Acked-by: Laurent Vivier From: Greg Kurz Running a guest with 128 NUMA nodes crashes QEMU: ../../util/error.c:59: error_setv: Assertion `*errp == NULL' failed. The crash happens when setting the FWNMI migration blocker: 2861 if (spapr_get_cap(spapr, SPAPR_CAP_FWNMI) == SPAPR_CAP_ON) { 2862 /* Create the error string for live migration blocker */ 2863 error_setg(&spapr->fwnmi_migration_blocker, 2864 "A machine check is being handled during migration. The handler" 2865 "may run and log hardware error on the destination"); 2866 } Inspection reveals that papr->fwnmi_migration_blocker isn't NULL: (gdb) p spapr->fwnmi_migration_blocker $1 = (Error *) 0x8000000004000000 Since this is the only place where papr->fwnmi_migration_blocker is set, this means someone wrote there in our back. Further analysis points to spapr_numa_associativity_init(), especially the part that initializes the associative arrays for NVLink GPUs: max_nodes_with_gpus = nb_numa_nodes + NVGPU_MAX_NUM; ie. max_nodes_with_gpus = 128 + 6, but the array isn't sized to accommodate the 6 extra nodes: struct SpaprMachineState { . . . uint32_t numa_assoc_array[MAX_NODES][NUMA_ASSOC_SIZE]; Error *fwnmi_migration_blocker; }; and the following loops happily overwrite spapr->fwnmi_migration_blocker, and probably more: for (i = nb_numa_nodes; i < max_nodes_with_gpus; i++) { spapr->numa_assoc_array[i][0] = cpu_to_be32(MAX_DISTANCE_REF_POINTS); for (j = 1; j < MAX_DISTANCE_REF_POINTS; j++) { uint32_t gpu_assoc = smc->pre_5_1_assoc_refpoints ? SPAPR_GPU_NUMA_ID : cpu_to_be32(i); spapr->numa_assoc_array[i][j] = gpu_assoc; } spapr->numa_assoc_array[i][MAX_DISTANCE_REF_POINTS] = cpu_to_be32(i); } Fix the size of the array. This requires "hw/ppc/spapr.h" to see NVGPU_MAX_NUM. Including "hw/pci-host/spapr.h" introduces a circular dependency that breaks the build, so this moves the definition of NVGPU_MAX_NUM to "hw/ppc/spapr.h" instead. Reported-by: Min Deng BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1908693 Fixes: dd7e1d7ae431 ("spapr_numa: move NVLink2 associativity handling to spapr_numa.c") Cc: danielhb413@gmail.com Signed-off-by: Greg Kurz Message-Id: <160829960428.734871.12634150161215429514.stgit@bahia.lan> Reviewed-by: Daniel Henrique Barboza Signed-off-by: David Gibson (cherry picked from commit 30499fdd9883026e106d74e8199e2f1311fd4011) Signed-off-by: Greg Kurz Signed-off-by: Danilo C. L. de Paula --- include/hw/pci-host/spapr.h | 2 -- include/hw/ppc/spapr.h | 5 ++++- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/include/hw/pci-host/spapr.h b/include/hw/pci-host/spapr.h index 4f58f0223b..bd014823a9 100644 --- a/include/hw/pci-host/spapr.h +++ b/include/hw/pci-host/spapr.h @@ -115,8 +115,6 @@ struct SpaprPhbState { #define SPAPR_PCI_NV2RAM64_WIN_BASE SPAPR_PCI_LIMIT #define SPAPR_PCI_NV2RAM64_WIN_SIZE (2 * TiB) /* For up to 6 GPUs 256GB each */ -/* Max number of these GPUsper a physical box */ -#define NVGPU_MAX_NUM 6 /* Max number of NVLinks per GPU in any physical box */ #define NVGPU_MAX_LINKS 3 diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h index ba2d81404b..28bbf07f8f 100644 --- a/include/hw/ppc/spapr.h +++ b/include/hw/ppc/spapr.h @@ -112,6 +112,9 @@ typedef enum { #define NUMA_ASSOC_SIZE (MAX_DISTANCE_REF_POINTS + 1) #define VCPU_ASSOC_SIZE (NUMA_ASSOC_SIZE + 1) +/* Max number of these GPUsper a physical box */ +#define NVGPU_MAX_NUM 6 + typedef struct SpaprCapabilities SpaprCapabilities; struct SpaprCapabilities { uint8_t caps[SPAPR_CAP_NUM]; @@ -243,7 +246,7 @@ struct SpaprMachineState { unsigned gpu_numa_id; SpaprTpmProxy *tpm_proxy; - uint32_t numa_assoc_array[MAX_NODES][NUMA_ASSOC_SIZE]; + uint32_t numa_assoc_array[MAX_NODES + NVGPU_MAX_NUM][NUMA_ASSOC_SIZE]; Error *fwnmi_migration_blocker; }; -- 2.18.4