From b4e5a4bffda0d5dd79c87c66f28a5fac87182e30 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Mon, 10 Mar 2014 21:30:16 +0200 Subject: acpi-build: don't access unaligned addresses casting an unaligned address to e.g. uint32_t can trigger undefined behaviour in C. Replace cast + assignment with memcpy. Reported-by: Peter Maydell Signed-off-by: Michael S. Tsirkin --- hw/i386/acpi-build.c | 31 ++++++++++++++++--------------- 1 file changed, 16 insertions(+), 15 deletions(-) (limited to 'hw/i386') diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c index b667d31de5..7ecfd7004b 100644 --- a/hw/i386/acpi-build.c +++ b/hw/i386/acpi-build.c @@ -466,9 +466,15 @@ static void acpi_align_size(GArray *blob, unsigned align) g_array_set_size(blob, ROUND_UP(acpi_data_len(blob), align)); } -/* Get pointer within table in a safe manner */ -#define ACPI_BUILD_PTR(table, size, off, type) \ - ((type *)(acpi_data_get_ptr(table, size, off, sizeof(type)))) +/* Set a value within table in a safe manner */ +#define ACPI_BUILD_SET_LE(table, size, off, bits, val) \ + do { \ + uint64_t ACPI_BUILD_SET_LE_val = cpu_to_le64(val); \ + memcpy(acpi_data_get_ptr(table, size, off, \ + (bits) / BITS_PER_BYTE), \ + &ACPI_BUILD_SET_LE_val, \ + (bits) / BITS_PER_BYTE); \ + } while (0) static inline void *acpi_data_get_ptr(uint8_t *table_data, unsigned table_size, unsigned off, unsigned size) @@ -974,22 +980,17 @@ static void build_pci_bus_end(PCIBus *bus, void *bus_state) static void patch_pci_windows(PcPciInfo *pci, uint8_t *start, unsigned size) { - *ACPI_BUILD_PTR(start, size, acpi_pci32_start[0], uint32_t) = - cpu_to_le32(pci->w32.begin); + ACPI_BUILD_SET_LE(start, size, acpi_pci32_start[0], 32, pci->w32.begin); - *ACPI_BUILD_PTR(start, size, acpi_pci32_end[0], uint32_t) = - cpu_to_le32(pci->w32.end - 1); + ACPI_BUILD_SET_LE(start, size, acpi_pci32_end[0], 32, pci->w32.end - 1); if (pci->w64.end || pci->w64.begin) { - *ACPI_BUILD_PTR(start, size, acpi_pci64_valid[0], uint8_t) = 1; - *ACPI_BUILD_PTR(start, size, acpi_pci64_start[0], uint64_t) = - cpu_to_le64(pci->w64.begin); - *ACPI_BUILD_PTR(start, size, acpi_pci64_end[0], uint64_t) = - cpu_to_le64(pci->w64.end - 1); - *ACPI_BUILD_PTR(start, size, acpi_pci64_length[0], uint64_t) = - cpu_to_le64(pci->w64.end - pci->w64.begin); + ACPI_BUILD_SET_LE(start, size, acpi_pci64_valid[0], 8, 1); + ACPI_BUILD_SET_LE(start, size, acpi_pci64_start[0], 64, pci->w64.begin); + ACPI_BUILD_SET_LE(start, size, acpi_pci64_end[0], 64, pci->w64.end - 1); + ACPI_BUILD_SET_LE(start, size, acpi_pci64_length[0], 64, pci->w64.end - pci->w64.begin); } else { - *ACPI_BUILD_PTR(start, size, acpi_pci64_valid[0], uint8_t) = 0; + ACPI_BUILD_SET_LE(start, size, acpi_pci64_valid[0], 8, 0); } } -- cgit v1.2.1