From caacea4b2ed7ccf3f32ad03b810146f56125626b Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Tue, 9 Oct 2018 18:25:01 +0100 Subject: [PATCH] block/qcow2-bitmap: Don't take address of fields in packed structs Taking the address of a field in a packed struct is a bad idea, because it might not be actually aligned enough for that pointer type (and thus cause a crash on dereference on some host architectures). Newer versions of clang warn about this. Avoid the bug by not using the "modify in place" byte swapping functions. There are a few places where the in-place swap function is used on something other than a packed struct field; we convert those anyway, for consistency. This patch was produced with the following spatch script: @@ expression E; @@ -be16_to_cpus(&E); +E = be16_to_cpu(E); @@ expression E; @@ -be32_to_cpus(&E); +E = be32_to_cpu(E); @@ expression E; @@ -be64_to_cpus(&E); +E = be64_to_cpu(E); @@ expression E; @@ -cpu_to_be16s(&E); +E = cpu_to_be16(E); @@ expression E; @@ -cpu_to_be32s(&E); +E = cpu_to_be32(E); @@ expression E; @@ -cpu_to_be64s(&E); +E = cpu_to_be64(E); Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson Tested-by: John Snow Reviewed-by: John Snow Signed-off-by: Kevin Wolf --- block/qcow2-bitmap.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/block/qcow2-bitmap.c b/block/qcow2-bitmap.c index b5f1b3563d..accebef4cf 100644 --- a/block/qcow2-bitmap.c +++ b/block/qcow2-bitmap.c @@ -118,7 +118,7 @@ static inline void bitmap_table_to_be(uint64_t *bitmap_table, size_t size) size_t i; for (i = 0; i < size; ++i) { - cpu_to_be64s(&bitmap_table[i]); + bitmap_table[i] = cpu_to_be64(bitmap_table[i]); } } @@ -231,7 +231,7 @@ static int bitmap_table_load(BlockDriverState *bs, Qcow2BitmapTable *tb, } for (i = 0; i < tb->size; ++i) { - be64_to_cpus(&table[i]); + table[i] = be64_to_cpu(table[i]); ret = check_table_entry(table[i], s->cluster_size); if (ret < 0) { goto fail; @@ -394,20 +394,20 @@ fail: static inline void bitmap_dir_entry_to_cpu(Qcow2BitmapDirEntry *entry) { - be64_to_cpus(&entry->bitmap_table_offset); - be32_to_cpus(&entry->bitmap_table_size); - be32_to_cpus(&entry->flags); - be16_to_cpus(&entry->name_size); - be32_to_cpus(&entry->extra_data_size); + entry->bitmap_table_offset = be64_to_cpu(entry->bitmap_table_offset); + entry->bitmap_table_size = be32_to_cpu(entry->bitmap_table_size); + entry->flags = be32_to_cpu(entry->flags); + entry->name_size = be16_to_cpu(entry->name_size); + entry->extra_data_size = be32_to_cpu(entry->extra_data_size); } static inline void bitmap_dir_entry_to_be(Qcow2BitmapDirEntry *entry) { - cpu_to_be64s(&entry->bitmap_table_offset); - cpu_to_be32s(&entry->bitmap_table_size); - cpu_to_be32s(&entry->flags); - cpu_to_be16s(&entry->name_size); - cpu_to_be32s(&entry->extra_data_size); + entry->bitmap_table_offset = cpu_to_be64(entry->bitmap_table_offset); + entry->bitmap_table_size = cpu_to_be32(entry->bitmap_table_size); + entry->flags = cpu_to_be32(entry->flags); + entry->name_size = cpu_to_be16(entry->name_size); + entry->extra_data_size = cpu_to_be32(entry->extra_data_size); } static inline int calc_dir_entry_size(size_t name_size, size_t extra_data_size)