From a5fdff18a737f3c70fbb915a9257440028ffde91 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Tue, 9 Oct 2018 18:25:00 +0100 Subject: [PATCH] block/qcow: 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/qcow.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) diff --git a/block/qcow.c b/block/qcow.c index 385d935258..4518cb4c35 100644 --- a/block/qcow.c +++ b/block/qcow.c @@ -140,14 +140,14 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags, if (ret < 0) { goto fail; } - be32_to_cpus(&header.magic); - be32_to_cpus(&header.version); - be64_to_cpus(&header.backing_file_offset); - be32_to_cpus(&header.backing_file_size); - be32_to_cpus(&header.mtime); - be64_to_cpus(&header.size); - be32_to_cpus(&header.crypt_method); - be64_to_cpus(&header.l1_table_offset); + header.magic = be32_to_cpu(header.magic); + header.version = be32_to_cpu(header.version); + header.backing_file_offset = be64_to_cpu(header.backing_file_offset); + header.backing_file_size = be32_to_cpu(header.backing_file_size); + header.mtime = be32_to_cpu(header.mtime); + header.size = be64_to_cpu(header.size); + header.crypt_method = be32_to_cpu(header.crypt_method); + header.l1_table_offset = be64_to_cpu(header.l1_table_offset); if (header.magic != QCOW_MAGIC) { error_setg(errp, "Image not in qcow format"); @@ -270,7 +270,7 @@ static int qcow_open(BlockDriverState *bs, QDict *options, int flags, } for(i = 0;i < s->l1_size; i++) { - be64_to_cpus(&s->l1_table[i]); + s->l1_table[i] = be64_to_cpu(s->l1_table[i]); } /* alloc L2 cache (max. 64k * 16 * 8 = 8 MB) */ -- 2.11.0