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From: Kevin Wolf <kwolf@redhat.com>
To: qemu-block@nongnu.org
Date: Mon, 5 Nov 2018 17:37:13 +0100
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Subject: [Qemu-devel] [PULL 05/36] block/qcow: Don't take address of fields
in packed structs
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Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org
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From: Peter Maydell <peter.maydell@linaro.org>
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 =3D be16_to_cpu(E);
@@
expression E;
@@
-be32_to_cpus(&E);
+E =3D be32_to_cpu(E);
@@
expression E;
@@
-be64_to_cpus(&E);
+E =3D be64_to_cpu(E);
@@
expression E;
@@
-cpu_to_be16s(&E);
+E =3D cpu_to_be16(E);
@@
expression E;
@@
-cpu_to_be32s(&E);
+E =3D cpu_to_be32(E);
@@
expression E;
@@
-cpu_to_be64s(&E);
+E =3D 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>
---
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 *opt=
ions, 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 =3D be32_to_cpu(header.magic);
+ header.version =3D be32_to_cpu(header.version);
+ header.backing_file_offset =3D be64_to_cpu(header.backing_file_offset);
+ header.backing_file_size =3D be32_to_cpu(header.backing_file_size);
+ header.mtime =3D be32_to_cpu(header.mtime);
+ header.size =3D be64_to_cpu(header.size);
+ header.crypt_method =3D be32_to_cpu(header.crypt_method);
+ header.l1_table_offset =3D be64_to_cpu(header.l1_table_offset);
=20
if (header.magic !=3D QCOW_MAGIC) {
error_setg(errp, "Image not in qcow format");
@@ -270,7 +270,7 @@ static int qcow_open(BlockDriverState *bs, QDict *optio=
ns, int flags,
}
=20
for(i =3D 0;i < s->l1_size; i++) {
- be64_to_cpus(&s->l1_table[i]);
+ s->l1_table[i] =3D be64_to_cpu(s->l1_table[i]);
}
=20
/* alloc L2 cache (max. 64k * 16 * 8 =3D 8 MB) */
--=20
2.19.1