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From: Kevin Wolf <kwolf@redhat.com>
To: qemu-block@nongnu.org
Date: Mon, 5 Nov 2018 17:37:12 +0100
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Subject: [Qemu-devel] [PULL 04/36] block/qcow2: 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
(and hand-editing to fold a few resulting overlength lines):
@@
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/qcow2.c | 64 +++++++++++++++++++++++++++------------------------
1 file changed, 34 insertions(+), 30 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index 30689b7688..de94b290e6 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -210,8 +210,8 @@ static int qcow2_read_extensions(BlockDriverState *bs, =
uint64_t start_offset,
"pread fail from offset %" PRIu64, offset);
return 1;
}
- be32_to_cpus(&ext.magic);
- be32_to_cpus(&ext.len);
+ ext.magic =3D be32_to_cpu(ext.magic);
+ ext.len =3D be32_to_cpu(ext.len);
offset +=3D sizeof(ext);
#ifdef DEBUG_EXT
printf("ext.magic =3D 0x%x\n", ext.magic);
@@ -279,8 +279,8 @@ static int qcow2_read_extensions(BlockDriverState *bs, =
uint64_t start_offset,
"Unable to read CRYPTO header extension");
return ret;
}
- be64_to_cpus(&s->crypto_header.offset);
- be64_to_cpus(&s->crypto_header.length);
+ s->crypto_header.offset =3D be64_to_cpu(s->crypto_header.offse=
t);
+ s->crypto_header.length =3D be64_to_cpu(s->crypto_header.lengt=
h);
=20
if ((s->crypto_header.offset % s->cluster_size) !=3D 0) {
error_setg(errp, "Encryption header offset '%" PRIu64 "' i=
s "
@@ -342,9 +342,11 @@ static int qcow2_read_extensions(BlockDriverState *bs,=
uint64_t start_offset,
return -EINVAL;
}
=20
- be32_to_cpus(&bitmaps_ext.nb_bitmaps);
- be64_to_cpus(&bitmaps_ext.bitmap_directory_size);
- be64_to_cpus(&bitmaps_ext.bitmap_directory_offset);
+ bitmaps_ext.nb_bitmaps =3D be32_to_cpu(bitmaps_ext.nb_bitmaps);
+ bitmaps_ext.bitmap_directory_size =3D
+ be64_to_cpu(bitmaps_ext.bitmap_directory_size);
+ bitmaps_ext.bitmap_directory_offset =3D
+ be64_to_cpu(bitmaps_ext.bitmap_directory_offset);
=20
if (bitmaps_ext.nb_bitmaps > QCOW2_MAX_BITMAPS) {
error_setg(errp,
@@ -1159,19 +1161,20 @@ static int coroutine_fn qcow2_do_open(BlockDriverSt=
ate *bs, QDict *options,
error_setg_errno(errp, -ret, "Could not read qcow2 header");
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);
- be64_to_cpus(&header.size);
- be32_to_cpus(&header.cluster_bits);
- be32_to_cpus(&header.crypt_method);
- be64_to_cpus(&header.l1_table_offset);
- be32_to_cpus(&header.l1_size);
- be64_to_cpus(&header.refcount_table_offset);
- be32_to_cpus(&header.refcount_table_clusters);
- be64_to_cpus(&header.snapshots_offset);
- be32_to_cpus(&header.nb_snapshots);
+ 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.size =3D be64_to_cpu(header.size);
+ header.cluster_bits =3D be32_to_cpu(header.cluster_bits);
+ header.crypt_method =3D be32_to_cpu(header.crypt_method);
+ header.l1_table_offset =3D be64_to_cpu(header.l1_table_offset);
+ header.l1_size =3D be32_to_cpu(header.l1_size);
+ header.refcount_table_offset =3D be64_to_cpu(header.refcount_table_off=
set);
+ header.refcount_table_clusters =3D
+ be32_to_cpu(header.refcount_table_clusters);
+ header.snapshots_offset =3D be64_to_cpu(header.snapshots_offset);
+ header.nb_snapshots =3D be32_to_cpu(header.nb_snapshots);
=20
if (header.magic !=3D QCOW_MAGIC) {
error_setg(errp, "Image is not in qcow2 format");
@@ -1207,11 +1210,12 @@ static int coroutine_fn qcow2_do_open(BlockDriverSt=
ate *bs, QDict *options,
header.refcount_order =3D 4;
header.header_length =3D 72;
} else {
- be64_to_cpus(&header.incompatible_features);
- be64_to_cpus(&header.compatible_features);
- be64_to_cpus(&header.autoclear_features);
- be32_to_cpus(&header.refcount_order);
- be32_to_cpus(&header.header_length);
+ header.incompatible_features =3D
+ be64_to_cpu(header.incompatible_features);
+ header.compatible_features =3D be64_to_cpu(header.compatible_featu=
res);
+ header.autoclear_features =3D be64_to_cpu(header.autoclear_feature=
s);
+ header.refcount_order =3D be32_to_cpu(header.refcount_order);
+ header.header_length =3D be32_to_cpu(header.header_length);
=20
if (header.header_length < 104) {
error_setg(errp, "qcow2 header too short");
@@ -1400,7 +1404,7 @@ static int coroutine_fn qcow2_do_open(BlockDriverStat=
e *bs, QDict *options,
goto fail;
}
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
@@ -2392,13 +2396,13 @@ int qcow2_update_header(BlockDriverState *bs)
=20
/* Full disk encryption header pointer extension */
if (s->crypto_header.offset !=3D 0) {
- cpu_to_be64s(&s->crypto_header.offset);
- cpu_to_be64s(&s->crypto_header.length);
+ s->crypto_header.offset =3D cpu_to_be64(s->crypto_header.offset);
+ s->crypto_header.length =3D cpu_to_be64(s->crypto_header.length);
ret =3D header_ext_add(buf, QCOW2_EXT_MAGIC_CRYPTO_HEADER,
&s->crypto_header, sizeof(s->crypto_header),
buflen);
- be64_to_cpus(&s->crypto_header.offset);
- be64_to_cpus(&s->crypto_header.length);
+ s->crypto_header.offset =3D be64_to_cpu(s->crypto_header.offset);
+ s->crypto_header.length =3D be64_to_cpu(s->crypto_header.length);
if (ret < 0) {
goto fail;
}
--=20
2.19.1