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block/qcow2: Don't take address of fields in packed structs

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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 = 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 18:24:59 +01:00 committed by Kevin Wolf
parent cf67b692b3
commit 3b698f52f9
1 changed files with 34 additions and 30 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

64
block/qcow2.c
View File

@ -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 = be32_to_cpu(ext.magic);
ext.len = be32_to_cpu(ext.len);
offset += sizeof(ext);
#ifdef DEBUG_EXT
printf("ext.magic = 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 = be64_to_cpu(s->crypto_header.offset);
s->crypto_header.length = be64_to_cpu(s->crypto_header.length);
if ((s->crypto_header.offset % s->cluster_size) != 0) {
error_setg(errp, "Encryption header offset '%" PRIu64 "' is "
@ -342,9 +342,11 @@ static int qcow2_read_extensions(BlockDriverState *bs, uint64_t start_offset,
return -EINVAL;
}
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 = be32_to_cpu(bitmaps_ext.nb_bitmaps);
bitmaps_ext.bitmap_directory_size =
be64_to_cpu(bitmaps_ext.bitmap_directory_size);
bitmaps_ext.bitmap_directory_offset =
be64_to_cpu(bitmaps_ext.bitmap_directory_offset);
if (bitmaps_ext.nb_bitmaps > QCOW2_MAX_BITMAPS) {
error_setg(errp,
@ -1159,19 +1161,20 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *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 = 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.size = be64_to_cpu(header.size);
header.cluster_bits = be32_to_cpu(header.cluster_bits);
header.crypt_method = be32_to_cpu(header.crypt_method);
header.l1_table_offset = be64_to_cpu(header.l1_table_offset);
header.l1_size = be32_to_cpu(header.l1_size);
header.refcount_table_offset = be64_to_cpu(header.refcount_table_offset);
header.refcount_table_clusters =
be32_to_cpu(header.refcount_table_clusters);
header.snapshots_offset = be64_to_cpu(header.snapshots_offset);
header.nb_snapshots = be32_to_cpu(header.nb_snapshots);
if (header.magic != QCOW_MAGIC) {
error_setg(errp, "Image is not in qcow2 format");
@ -1207,11 +1210,12 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
header.refcount_order = 4;
header.header_length = 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 =
be64_to_cpu(header.incompatible_features);
header.compatible_features = be64_to_cpu(header.compatible_features);
header.autoclear_features = be64_to_cpu(header.autoclear_features);
header.refcount_order = be32_to_cpu(header.refcount_order);
header.header_length = be32_to_cpu(header.header_length);
if (header.header_length < 104) {
error_setg(errp, "qcow2 header too short");
@ -1400,7 +1404,7 @@ static int coroutine_fn qcow2_do_open(BlockDriverState *bs, QDict *options,
goto fail;
}
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]);
}
}
@ -2392,13 +2396,13 @@ int qcow2_update_header(BlockDriverState *bs)
/* Full disk encryption header pointer extension */
if (s->crypto_header.offset != 0) {
cpu_to_be64s(&s->crypto_header.offset);
cpu_to_be64s(&s->crypto_header.length);
s->crypto_header.offset = cpu_to_be64(s->crypto_header.offset);
s->crypto_header.length = cpu_to_be64(s->crypto_header.length);
ret = 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 = be64_to_cpu(s->crypto_header.offset);
s->crypto_header.length = be64_to_cpu(s->crypto_header.length);
if (ret < 0) {
goto fail;
}