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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 <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: John Snow <jsnow@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Peter Maydell 2018-10-09 18:25:00 +01:00 committed by Kevin Wolf
parent 3b698f52f9
commit a5fdff18a7
1 changed files with 9 additions and 9 deletions
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18
block/qcow.c
View File

@ -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) */