From 69e2155268495a016c026d8e002d93f81b615a0f Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Fri, 24 Jun 2016 18:55:44 +0200 Subject: [PATCH 15/33] acpi: make bios_linker_loader_add_checksum() API offset based RH-Author: Stefan Hajnoczi Message-id: <1466794559-27963-8-git-send-email-stefanha@redhat.com> Patchwork-id: 70774 O-Subject: [RHEV-7.3 qemu-kvm-rhev PATCH v2 07/22] acpi: make bios_linker_loader_add_checksum() API offset based Bugzilla: 1270345 RH-Acked-by: Paolo Bonzini RH-Acked-by: Igor Mammedov RH-Acked-by: Michael S. Tsirkin From: Igor Mammedov It should help to make clear that bios_linker works in terms of offsets within a file. Also it should prevent mistakes where user passes as arguments pointers to unrelated to file blobs. While at it, considering that it's a ACPI checksum and it's initial value must be 0, move checksum field zeroing into bios_linker_loader_add_checksum() instead of doing it at every call site manually before bios_linker_loader_add_checksum() is called. In addition add extra boundary checks. Signed-off-by: Igor Mammedov Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin (cherry picked from commit 28213cb6a61a724e2cb1e3a76d2bb17aa0ce9b36) Signed-off-by: Stefan Hajnoczi Signed-off-by: Miroslav Rezanina --- hw/acpi/aml-build.c | 5 +++-- hw/acpi/bios-linker-loader.c | 36 +++++++++++++----------------------- hw/arm/virt-acpi-build.c | 5 ++--- hw/i386/acpi-build.c | 5 ++--- include/hw/acpi/bios-linker-loader.h | 4 ++-- 5 files changed, 22 insertions(+), 33 deletions(-) diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c index 5a4aeb1..87def65 100644 --- a/hw/acpi/aml-build.c +++ b/hw/acpi/aml-build.c @@ -1476,6 +1476,8 @@ build_header(BIOSLinker *linker, GArray *table_data, AcpiTableHeader *h, const char *sig, int len, uint8_t rev, const char *oem_id, const char *oem_table_id) { + unsigned tbl_offset = (char *)h - table_data->data; + unsigned checksum_offset = (char *)&h->checksum - table_data->data; memcpy(&h->signature, sig, 4); h->length = cpu_to_le32(len); h->revision = rev; @@ -1496,10 +1498,9 @@ build_header(BIOSLinker *linker, GArray *table_data, h->oem_revision = cpu_to_le32(1); memcpy(h->asl_compiler_id, ACPI_BUILD_APPNAME4, 4); h->asl_compiler_revision = cpu_to_le32(1); - h->checksum = 0; /* Checksum to be filled in by Guest linker */ bios_linker_loader_add_checksum(linker, ACPI_BUILD_TABLE_FILE, - h, len, &h->checksum); + tbl_offset, len, checksum_offset); } void *acpi_data_push(GArray *table_data, unsigned size) diff --git a/hw/acpi/bios-linker-loader.c b/hw/acpi/bios-linker-loader.c index 3fb54dc..d963ebe 100644 --- a/hw/acpi/bios-linker-loader.c +++ b/hw/acpi/bios-linker-loader.c @@ -189,8 +189,8 @@ void bios_linker_loader_alloc(BIOSLinker *linker, } /* - * bios_linker_loader_add_checksum: ask guest to add checksum of file data - * into (same) file at the specified pointer. + * bios_linker_loader_add_checksum: ask guest to add checksum of ACPI + * table in the specified file at the specified offset. * * Checksum calculation simply sums -X for each byte X in the range * using 8-bit math (i.e. ACPI checksum). @@ -198,35 +198,25 @@ void bios_linker_loader_alloc(BIOSLinker *linker, * @linker: linker object instance * @file: file that includes the checksum to be calculated * and the data to be checksummed - * @start, @size: range of data to checksum - * @checksum: location of the checksum to be patched within file blob - * - * Notes: - * - checksum byte initial value must have been pushed into blob - * associated with @file and reside at address @checksum. - * - @size bytes must have been pushed into blob associated wtih @file - * and reside at address @start. - * - Guest calculates checksum of specified range of data, result is added to - * initial value at @checksum into copy of @file in Guest memory. - * - Range might include the checksum itself. - * - To avoid confusion, caller must always put 0x0 at @checksum. - * - @file must be loaded into Guest memory using bios_linker_loader_alloc + * @start_offset, @size: range of data in the file to checksum, + * relative to the start of file blob + * @checksum_offset: location of the checksum to be patched within file blob, + * relative to the start of file blob */ void bios_linker_loader_add_checksum(BIOSLinker *linker, const char *file_name, - void *start, unsigned size, - uint8_t *checksum) + unsigned start_offset, unsigned size, + unsigned checksum_offset) { BiosLinkerLoaderEntry entry; const BiosLinkerFileEntry *file = bios_linker_find_file(linker, file_name); - ptrdiff_t checksum_offset = (gchar *)checksum - file->blob->data; - ptrdiff_t start_offset = (gchar *)start - file->blob->data; - assert(checksum_offset >= 0); - assert(start_offset >= 0); - assert(checksum_offset + 1 <= file->blob->len); + assert(file); + assert(start_offset < file->blob->len); assert(start_offset + size <= file->blob->len); - assert(*checksum == 0x0); + assert(checksum_offset >= start_offset); + assert(checksum_offset + 1 <= start_offset + size); + *(file->blob->data + checksum_offset) = 0; memset(&entry, 0, sizeof entry); strncpy(entry.cksum.file, file_name, sizeof entry.cksum.file - 1); entry.command = cpu_to_le32(BIOS_LINKER_LOADER_COMMAND_ADD_CHECKSUM); diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c index 4dcc680..819033f 100644 --- a/hw/arm/virt-acpi-build.c +++ b/hw/arm/virt-acpi-build.c @@ -372,11 +372,10 @@ build_rsdp(GArray *rsdp_table, BIOSLinker *linker, unsigned rsdt_tbl_offset) ACPI_BUILD_RSDP_FILE, rsdt_pa_offset, rsdt_pa_size, ACPI_BUILD_TABLE_FILE, rsdt_tbl_offset); - rsdp->checksum = 0; /* Checksum to be filled by Guest linker */ bios_linker_loader_add_checksum(linker, ACPI_BUILD_RSDP_FILE, - rsdp, sizeof *rsdp, - &rsdp->checksum); + (char *)rsdp - rsdp_table->data, sizeof *rsdp, + (char *)&rsdp->checksum - rsdp_table->data); return rsdp_table; } diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c index 0ff6564..e2f3d8f 100644 --- a/hw/i386/acpi-build.c +++ b/hw/i386/acpi-build.c @@ -2612,11 +2612,10 @@ build_rsdp(GArray *rsdp_table, BIOSLinker *linker, unsigned rsdt_tbl_offset) ACPI_BUILD_RSDP_FILE, rsdt_pa_offset, rsdt_pa_size, ACPI_BUILD_TABLE_FILE, rsdt_tbl_offset); - rsdp->checksum = 0; /* Checksum to be filled by Guest linker */ bios_linker_loader_add_checksum(linker, ACPI_BUILD_RSDP_FILE, - rsdp, sizeof *rsdp, - &rsdp->checksum); + (char *)rsdp - rsdp_table->data, sizeof *rsdp, + (char *)&rsdp->checksum - rsdp_table->data); return rsdp_table; } diff --git a/include/hw/acpi/bios-linker-loader.h b/include/hw/acpi/bios-linker-loader.h index f666b7c..a05227e 100644 --- a/include/hw/acpi/bios-linker-loader.h +++ b/include/hw/acpi/bios-linker-loader.h @@ -17,8 +17,8 @@ void bios_linker_loader_alloc(BIOSLinker *linker, bool alloc_fseg); void bios_linker_loader_add_checksum(BIOSLinker *linker, const char *file, - void *start, unsigned size, - uint8_t *checksum); + unsigned start_offset, unsigned size, + unsigned checksum_offset); void bios_linker_loader_add_pointer(BIOSLinker *linker, const char *dest_file, -- 1.8.3.1