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Tsirkin" To: qemu-devel@nongnu.org Cc: Peter Maydell , David Woodhouse , David Woodhouse , Paolo Bonzini , Richard Henderson , Eduardo Habkost , Marcel Apfelbaum , Sergio Lopez , Marcelo Tosatti , Paul Durrant , kvm@vger.kernel.org Subject: [PULL v2 61/88] hw/i386/fw_cfg: Add etc/e820 to fw_cfg late Message-ID: <63592d296f1a6b1aea223d5a1bb2f20f2f0373e2.1719951168.git.mst@redhat.com> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-Mailer: git-send-email 2.27.0.106.g8ac3dc51b1 X-Mutt-Fcc: =sent Received-SPF: pass client-ip=170.10.133.124; envelope-from=mst@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, 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: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: David Woodhouse In e820_add_entry() the e820_table is reallocated with g_renew() to make space for a new entry. However, fw_cfg_arch_create() just uses the existing e820_table pointer. This leads to a use-after-free if anything adds a new entry after fw_cfg is set up. Shift the addition of the etc/e820 file to the machine done notifier, via a new fw_cfg_add_e820() function. Also make e820_table private and use an e820_get_table() accessor function for it, which sets a flag that will trigger an assert() for any *later* attempts to add to the table. Make e820_add_entry() return void, as most callers don't check for error anyway. Signed-off-by: David Woodhouse Message-Id: Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/i386/e820_memory_layout.h | 8 ++------ hw/i386/fw_cfg.h | 1 + hw/i386/e820_memory_layout.c | 17 ++++++++++++----- hw/i386/fw_cfg.c | 18 +++++++++++++----- hw/i386/microvm.c | 4 ++-- hw/i386/pc.c | 1 + target/i386/kvm/kvm.c | 6 +----- target/i386/kvm/xen-emu.c | 7 +------ 8 files changed, 33 insertions(+), 29 deletions(-) diff --git a/hw/i386/e820_memory_layout.h b/hw/i386/e820_memory_layout.h index 7c239aa033..b50acfa201 100644 --- a/hw/i386/e820_memory_layout.h +++ b/hw/i386/e820_memory_layout.h @@ -22,13 +22,9 @@ struct e820_entry { uint32_t type; } QEMU_PACKED __attribute((__aligned__(4))); -extern struct e820_entry *e820_table; - -int e820_add_entry(uint64_t address, uint64_t length, uint32_t type); -int e820_get_num_entries(void); +void e820_add_entry(uint64_t address, uint64_t length, uint32_t type); bool e820_get_entry(int index, uint32_t type, uint64_t *address, uint64_t *length); - - +int e820_get_table(struct e820_entry **table); #endif diff --git a/hw/i386/fw_cfg.h b/hw/i386/fw_cfg.h index 92e310f5fd..e560fd7be8 100644 --- a/hw/i386/fw_cfg.h +++ b/hw/i386/fw_cfg.h @@ -27,5 +27,6 @@ void fw_cfg_build_smbios(PCMachineState *pcms, FWCfgState *fw_cfg, SmbiosEntryPointType ep_type); void fw_cfg_build_feature_control(MachineState *ms, FWCfgState *fw_cfg); void fw_cfg_add_acpi_dsdt(Aml *scope, FWCfgState *fw_cfg); +void fw_cfg_add_e820(FWCfgState *fw_cfg); #endif diff --git a/hw/i386/e820_memory_layout.c b/hw/i386/e820_memory_layout.c index 06970ac44a..3e848fb69c 100644 --- a/hw/i386/e820_memory_layout.c +++ b/hw/i386/e820_memory_layout.c @@ -11,22 +11,29 @@ #include "e820_memory_layout.h" static size_t e820_entries; -struct e820_entry *e820_table; +static struct e820_entry *e820_table; +static gboolean e820_done; -int e820_add_entry(uint64_t address, uint64_t length, uint32_t type) +void e820_add_entry(uint64_t address, uint64_t length, uint32_t type) { + assert(!e820_done); + /* new "etc/e820" file -- include ram and reserved entries */ e820_table = g_renew(struct e820_entry, e820_table, e820_entries + 1); e820_table[e820_entries].address = cpu_to_le64(address); e820_table[e820_entries].length = cpu_to_le64(length); e820_table[e820_entries].type = cpu_to_le32(type); e820_entries++; - - return e820_entries; } -int e820_get_num_entries(void) +int e820_get_table(struct e820_entry **table) { + e820_done = true; + + if (table) { + *table = e820_table; + } + return e820_entries; } diff --git a/hw/i386/fw_cfg.c b/hw/i386/fw_cfg.c index 7c43c325ef..0e4494627c 100644 --- a/hw/i386/fw_cfg.c +++ b/hw/i386/fw_cfg.c @@ -48,6 +48,15 @@ const char *fw_cfg_arch_key_name(uint16_t key) return NULL; } +/* Add etc/e820 late, once all regions should be present */ +void fw_cfg_add_e820(FWCfgState *fw_cfg) +{ + struct e820_entry *table; + int nr_e820 = e820_get_table(&table); + + fw_cfg_add_file(fw_cfg, "etc/e820", table, nr_e820 * sizeof(*table)); +} + void fw_cfg_build_smbios(PCMachineState *pcms, FWCfgState *fw_cfg, SmbiosEntryPointType ep_type) { @@ -60,6 +69,7 @@ void fw_cfg_build_smbios(PCMachineState *pcms, FWCfgState *fw_cfg, PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms); MachineClass *mc = MACHINE_GET_CLASS(pcms); X86CPU *cpu = X86_CPU(ms->possible_cpus->cpus[0].cpu); + int nr_e820; if (pcmc->smbios_defaults) { /* These values are guest ABI, do not change */ @@ -78,8 +88,9 @@ void fw_cfg_build_smbios(PCMachineState *pcms, FWCfgState *fw_cfg, } /* build the array of physical mem area from e820 table */ - mem_array = g_malloc0(sizeof(*mem_array) * e820_get_num_entries()); - for (i = 0, array_count = 0; i < e820_get_num_entries(); i++) { + nr_e820 = e820_get_table(NULL); + mem_array = g_malloc0(sizeof(*mem_array) * nr_e820); + for (i = 0, array_count = 0; i < nr_e820; i++) { uint64_t addr, len; if (e820_get_entry(i, E820_RAM, &addr, &len)) { @@ -138,9 +149,6 @@ FWCfgState *fw_cfg_arch_create(MachineState *ms, #endif fw_cfg_add_i32(fw_cfg, FW_CFG_IRQ0_OVERRIDE, 1); - fw_cfg_add_file(fw_cfg, "etc/e820", e820_table, - sizeof(struct e820_entry) * e820_get_num_entries()); - fw_cfg_add_bytes(fw_cfg, FW_CFG_HPET, &hpet_cfg, sizeof(hpet_cfg)); /* allocate memory for the NUMA channel: one (64bit) word for the number * of nodes, one word for each VCPU->node and one word for each node to diff --git a/hw/i386/microvm.c b/hw/i386/microvm.c index fec63cacfa..40edcee7af 100644 --- a/hw/i386/microvm.c +++ b/hw/i386/microvm.c @@ -324,8 +324,6 @@ static void microvm_memory_init(MicrovmMachineState *mms) fw_cfg_add_i16(fw_cfg, FW_CFG_MAX_CPUS, machine->smp.max_cpus); fw_cfg_add_i64(fw_cfg, FW_CFG_RAM_SIZE, (uint64_t)machine->ram_size); fw_cfg_add_i32(fw_cfg, FW_CFG_IRQ0_OVERRIDE, 1); - fw_cfg_add_file(fw_cfg, "etc/e820", e820_table, - sizeof(struct e820_entry) * e820_get_num_entries()); rom_set_fw(fw_cfg); @@ -586,9 +584,11 @@ static void microvm_machine_done(Notifier *notifier, void *data) { MicrovmMachineState *mms = container_of(notifier, MicrovmMachineState, machine_done); + X86MachineState *x86ms = X86_MACHINE(mms); acpi_setup_microvm(mms); dt_setup_microvm(mms); + fw_cfg_add_e820(x86ms->fw_cfg); } static void microvm_powerdown_req(Notifier *notifier, void *data) diff --git a/hw/i386/pc.c b/hw/i386/pc.c index 77415064c6..d2c29fbfcb 100644 --- a/hw/i386/pc.c +++ b/hw/i386/pc.c @@ -625,6 +625,7 @@ void pc_machine_done(Notifier *notifier, void *data) acpi_setup(); if (x86ms->fw_cfg) { fw_cfg_build_smbios(pcms, x86ms->fw_cfg, pcms->smbios_entry_point_type); + fw_cfg_add_e820(x86ms->fw_cfg); fw_cfg_build_feature_control(MACHINE(pcms), x86ms->fw_cfg); /* update FW_CFG_NB_CPUS to account for -device added CPUs */ fw_cfg_modify_i16(x86ms->fw_cfg, FW_CFG_NB_CPUS, x86ms->boot_cpus); diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index dd8b0f3313..bf182570fe 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -2706,11 +2706,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s) } /* Tell fw_cfg to notify the BIOS to reserve the range. */ - ret = e820_add_entry(identity_base, 0x4000, E820_RESERVED); - if (ret < 0) { - fprintf(stderr, "e820_add_entry() table is full\n"); - return ret; - } + e820_add_entry(identity_base, 0x4000, E820_RESERVED); shadow_mem = object_property_get_int(OBJECT(s), "kvm-shadow-mem", &error_abort); if (shadow_mem != -1) { diff --git a/target/i386/kvm/xen-emu.c b/target/i386/kvm/xen-emu.c index fc2c2321ac..2f89dc628e 100644 --- a/target/i386/kvm/xen-emu.c +++ b/target/i386/kvm/xen-emu.c @@ -176,12 +176,7 @@ int kvm_xen_init(KVMState *s, uint32_t hypercall_msr) s->xen_caps = xen_caps; /* Tell fw_cfg to notify the BIOS to reserve the range. */ - ret = e820_add_entry(XEN_SPECIAL_AREA_ADDR, XEN_SPECIAL_AREA_SIZE, - E820_RESERVED); - if (ret < 0) { - fprintf(stderr, "e820_add_entry() table is full\n"); - return ret; - } + e820_add_entry(XEN_SPECIAL_AREA_ADDR, XEN_SPECIAL_AREA_SIZE, E820_RESERVED); /* The pages couldn't be overlaid until KVM was initialized */ xen_primary_console_reset();