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-rw-r--r--src/kernel/xloop_file_fmt_qcow_main.c129
-rw-r--r--src/kernel/xloop_file_fmt_qcow_main.h1
2 files changed, 105 insertions, 25 deletions
diff --git a/src/kernel/xloop_file_fmt_qcow_main.c b/src/kernel/xloop_file_fmt_qcow_main.c
index 767698b..ae3ad81 100644
--- a/src/kernel/xloop_file_fmt_qcow_main.c
+++ b/src/kernel/xloop_file_fmt_qcow_main.c
@@ -58,6 +58,11 @@ static int __qcow_file_fmt_header_read(struct xloop_file_fmt *xlo_fmt, struct fi
dev_err(xloop_file_fmt_to_dev(xlo_fmt), "could not read QCOW header\n");
return len;
}
+ if (len != sizeof(*header)) {
+ dev_err(xloop_file_fmt_to_dev(xlo_fmt), "short read of QCOW header (%d/%d)\n",
+ (int)len, (int)sizeof(*header));
+ return -EIO;
+ }
header->magic = be32_to_cpu(header->magic);
header->version = be32_to_cpu(header->version);
@@ -184,6 +189,7 @@ static int __qcow_file_fmt_compression_init(struct xloop_file_fmt *xlo_fmt)
/* create cache for last compressed QCOW cluster */
qcow_data->cmp_last_coffset = ULLONG_MAX;
+ qcow_data->cmp_last_size = 0;
qcow_data->cmp_out_buf = vmalloc(qcow_data->cluster_size);
if (!qcow_data->cmp_out_buf) {
ret = -ENOMEM;
@@ -297,7 +303,7 @@ static ssize_t __qcow_file_fmt_dbgfs_ofs_read(struct file *file, char __user *bu
/* calculate and print the cluster offset */
ret = xloop_file_fmt_qcow_get_host_offset(xlo_fmt, offset, &cur_bytes, &host_offset, &type);
- if (ret < 0)
+ if (ret)
return -EINVAL;
offset_in_cluster = xloop_file_fmt_qcow_offset_into_cluster(qcow_data, offset);
@@ -660,18 +666,24 @@ static int qcow_file_fmt_init(struct xloop_file_fmt *xlo_fmt)
}
if (qcow_data->l1_size > 0) {
+ const int read_size = qcow_data->l1_size * QCOW_L1E_SIZE;
qcow_data->l1_table = vzalloc(round_up(qcow_data->l1_size * QCOW_L1E_SIZE, 512));
if (qcow_data->l1_table == NULL) {
ret = -ENOMEM;
goto free_qcow_data;
}
- len = kernel_read(xlo->xlo_backing_file, qcow_data->l1_table, qcow_data->l1_size * QCOW_L1E_SIZE,
- &qcow_data->l1_table_offset);
+ len = kernel_read(xlo->xlo_backing_file, qcow_data->l1_table, read_size, &qcow_data->l1_table_offset);
if (len < 0) {
dev_err(xloop_file_fmt_to_dev(xlo_fmt), "could not read L1 table\n");
ret = len;
goto free_l1_table;
}
+ if (len != read_size) {
+ dev_err(xloop_file_fmt_to_dev(xlo_fmt), "short read in L1 table (%d/%d)\n",
+ (int)len, read_size);
+ ret = -EIO;
+ goto free_l1_table;
+ }
for (i = 0; i < qcow_data->l1_size; i++)
qcow_data->l1_table[i] = be64_to_cpu(qcow_data->l1_table[i]);
}
@@ -773,7 +785,7 @@ static void qcow_file_fmt_exit(struct xloop_file_fmt *xlo_fmt)
* @dest - destination buffer, @dest_size bytes
* @src - source buffer, @src_size bytes
*
- * Returns: 0 on success
+ * Returns: actual decompressed bytes on success
* -EIO on fail
*/
static ssize_t __qcow_file_fmt_zlib_decompress(struct xloop_file_fmt *xlo_fmt, void *dest, size_t dest_size,
@@ -781,10 +793,11 @@ static ssize_t __qcow_file_fmt_zlib_decompress(struct xloop_file_fmt *xlo_fmt, v
{
struct xloop_file_fmt_qcow_data *qcow_data = xlo_fmt->private_data;
u8 zerostuff = 0;
- ssize_t ret = 0;
+ int ret;
ret = zlib_inflateReset(qcow_data->zlib_dstrm);
if (ret != Z_OK) {
+ dev_err(xloop_file_fmt_to_dev(xlo_fmt), "zlib reset error: %d\n", (int)ret);
ret = -EINVAL;
goto out;
}
@@ -806,9 +819,11 @@ static ssize_t __qcow_file_fmt_zlib_decompress(struct xloop_file_fmt *xlo_fmt, v
ret = zlib_inflate(qcow_data->zlib_dstrm, Z_FINISH);
}
if (ret != Z_STREAM_END) {
+ dev_err(xloop_file_fmt_to_dev(xlo_fmt), "zlib inflate error: %d\n", (int)ret);
ret = -EIO;
goto out;
}
+ ret = dest_size - qcow_data->zlib_dstrm->avail_out;
out:
return ret;
@@ -825,7 +840,7 @@ out:
* @dest - destination buffer, @dest_size bytes
* @src - source buffer, @src_size bytes
*
- * Returns: 0 on success
+ * Returns: actual decompressed bytes on success
* -EIO on any error
*/
static ssize_t __qcow_file_fmt_zstd_decompress(struct xloop_file_fmt *xlo_fmt, void *dest, size_t dest_size,
@@ -842,7 +857,8 @@ static ssize_t __qcow_file_fmt_zstd_decompress(struct xloop_file_fmt *xlo_fmt, v
zstd_ret = ZSTD_resetDStream(qcow_data->zstd_dstrm);
if (ZSTD_isError(zstd_ret)) {
- ret = -EIO;
+ dev_err(xloop_file_fmt_to_dev(xlo_fmt), "zstd reset error: %d\n", (int)zstd_ret);
+ ret = -EINVAL;
goto out;
}
@@ -863,10 +879,8 @@ static ssize_t __qcow_file_fmt_zstd_decompress(struct xloop_file_fmt *xlo_fmt, v
zstd_ret = ZSTD_decompressStream(qcow_data->zstd_dstrm, &output, &input);
- if (ZSTD_isError(zstd_ret)) {
- ret = -EIO;
+ if (ZSTD_isError(zstd_ret))
break;
- }
/*
* The ZSTD manual is vague about what to do if it reads
@@ -877,8 +891,9 @@ static ssize_t __qcow_file_fmt_zstd_decompress(struct xloop_file_fmt *xlo_fmt, v
* on each step.
*/
if (last_in_pos >= input.pos && last_out_pos >= output.pos) {
+ dev_err(xloop_file_fmt_to_dev(xlo_fmt), "zstd not making any progress\n");
ret = -EIO;
- break;
+ goto out;
}
}
/*
@@ -887,11 +902,17 @@ static ssize_t __qcow_file_fmt_zstd_decompress(struct xloop_file_fmt *xlo_fmt, v
* greater then the cluster size, possibly because of its
* damage.
*/
- if (zstd_ret > 0)
+ if (ZSTD_isError(zstd_ret)) {
+ dev_err(xloop_file_fmt_to_dev(xlo_fmt), "zstd decompress error: %d\n", (int)zstd_ret);
+ ret = -EIO;
+ } if (zstd_ret) {
+ dev_err(xloop_file_fmt_to_dev(xlo_fmt), "zstd incomplete frame at end of cluster\n");
ret = -EIO;
+ } else {
+ ret = output.pos;
+ }
out:
- ASSERT(ret == 0 || ret == -EIO);
return ret;
}
#endif
@@ -906,7 +927,7 @@ out:
* @dest - destination buffer, @dest_size bytes
* @src - source buffer, @src_size bytes
*
- * Returns: compressed size on success
+ * Returns: actual decompressed size on success
* a negative error code on failure
*/
static ssize_t __qcow_file_fmt_buffer_decompress(struct xloop_file_fmt *xlo_fmt, void *dest, size_t dest_size,
@@ -932,12 +953,29 @@ static ssize_t __qcow_file_fmt_buffer_decompress(struct xloop_file_fmt *xlo_fmt,
return decompress_fn(xlo_fmt, dest, dest_size, src, src_size);
}
+/*
+ * __qcow_file_fmt_read_compressed()
+ *
+ * Decompress @bytes of data starting at virtual @offset
+ * using the compression method defined by the image
+ * compression type and write them to @bvec
+ *
+ * @xlo_fmt - QCOW file format
+ * @bvec - io vector to write uncompressed data to
+ * @file_cluster_offset - offset to compressed cluster in qcow2
+ * @offset - virtual offset, as seen on loop device
+ * @bytes - number of bytes to read
+ * @bytes_done - how many bytes are actually already finished (when called after partial read)
+ *
+ * Returns: actual decompressed size on success
+ * a negative error code on failure
+ */
static int __qcow_file_fmt_read_compressed(struct xloop_file_fmt *xlo_fmt, struct bio_vec *bvec,
u64 file_cluster_offset, u64 offset, u64 bytes, u64 bytes_done)
{
struct xloop_file_fmt_qcow_data *qcow_data = xlo_fmt->private_data;
struct xloop_device *xlo = xloop_file_fmt_get_xlo(xlo_fmt);
- int ret = 0, csize, nb_csectors;
+ int ret;
u64 coffset;
u8 *in_buf = NULL;
ssize_t len;
@@ -948,10 +986,12 @@ static int __qcow_file_fmt_read_compressed(struct xloop_file_fmt *xlo_fmt, struc
int offset_in_cluster = xloop_file_fmt_qcow_offset_into_cluster(qcow_data, offset);
coffset = file_cluster_offset & qcow_data->cluster_offset_mask;
- nb_csectors = ((file_cluster_offset >> qcow_data->csize_shift) & qcow_data->csize_mask) + 1;
- csize = nb_csectors * QCOW_COMPRESSED_SECTOR_SIZE - (coffset & ~QCOW_COMPRESSED_SECTOR_MASK);
if (qcow_data->cmp_last_coffset != coffset) {
+ int csize, nb_csectors;
+
+ nb_csectors = ((file_cluster_offset >> qcow_data->csize_shift) & qcow_data->csize_mask) + 1;
+ csize = nb_csectors * QCOW_COMPRESSED_SECTOR_SIZE - (coffset & ~QCOW_COMPRESSED_SECTOR_MASK);
in_buf = vmalloc(csize);
if (!in_buf) {
qcow_data->cmp_last_coffset = ULLONG_MAX;
@@ -961,16 +1001,38 @@ static int __qcow_file_fmt_read_compressed(struct xloop_file_fmt *xlo_fmt, struc
len = kernel_read(xlo->xlo_backing_file, in_buf, csize, &coffset);
if (len < 0) {
qcow_data->cmp_last_coffset = ULLONG_MAX;
+ dev_err(xloop_file_fmt_to_dev(xlo_fmt), "error %d reading compressed cluster at %llu\n",
+ (int)len, coffset);
ret = len;
goto out_free_in_buf;
}
-
- if (__qcow_file_fmt_buffer_decompress(xlo_fmt, qcow_data->cmp_out_buf, qcow_data->cluster_size, in_buf,
- csize) < 0) {
+ if (len != csize) {
qcow_data->cmp_last_coffset = ULLONG_MAX;
+ dev_err(xloop_file_fmt_to_dev(xlo_fmt), "short read in compressed cluster at %llu (%d/%d)\n",
+ coffset, (int)len, csize);
ret = -EIO;
goto out_free_in_buf;
}
+
+ ret = __qcow_file_fmt_buffer_decompress(xlo_fmt, qcow_data->cmp_out_buf,
+ qcow_data->cluster_size, in_buf, csize);
+ if (ret <= 0) {
+ qcow_data->cmp_last_coffset = ULLONG_MAX;
+ if (ret == 0) {
+ dev_err(xloop_file_fmt_to_dev(xlo_fmt), "decompressed cluster at %llu is empty\n",
+ coffset);
+ ret = -EIO;
+ }
+ goto out_free_in_buf;
+ }
+ qcow_data->cmp_last_size = ret;
+ }
+
+ if (offset_in_cluster + bytes > qcow_data->cmp_last_size) {
+ dev_err(xloop_file_fmt_to_dev(xlo_fmt), "read %d bytes from compressed cluster of size %d\n",
+ (int)(offset_in_cluster + bytes), qcow_data->cmp_last_size);
+ ret = -EIO;
+ goto out_free_in_buf;
}
ASSERT(bytes <= bvec->bv_len);
@@ -986,6 +1048,7 @@ static int __qcow_file_fmt_read_compressed(struct xloop_file_fmt *xlo_fmt, struc
#else
bvec_kunmap_irq(data, &irq_flags);
#endif
+ ret = bytes;
out_free_in_buf:
vfree(in_buf);
@@ -1011,14 +1074,16 @@ static int __qcow_file_fmt_read_bvec(struct xloop_file_fmt *xlo_fmt, struct bio_
ssize_t len;
loff_t pos_read;
+ /* bvec_kmap expects the passed bvec to only contain a single page */
+ ASSERT(bvec->bv_len <= PAGE_SIZE);
bytes = bvec->bv_len;
while (bytes != 0) {
- /* prepare next request */
+ /* prepare next request. if this spans a cluster boundary, this will be clamped */
cur_bytes = bytes;
ret = xloop_file_fmt_qcow_get_host_offset(xlo_fmt, *ppos, &cur_bytes, &host_offset, &type);
- if (ret < 0)
+ if (ret)
goto fail;
offset_in_cluster = xloop_file_fmt_qcow_offset_into_cluster(qcow_data, *ppos);
@@ -1046,6 +1111,12 @@ static int __qcow_file_fmt_read_bvec(struct xloop_file_fmt *xlo_fmt, struct bio_
ret = __qcow_file_fmt_read_compressed(xlo_fmt, bvec, host_offset, *ppos, cur_bytes, bytes_done);
if (ret < 0)
goto fail;
+ if (len == 0) {
+ dev_err(xloop_file_fmt_to_dev(xlo_fmt), "Unexpected empty read in compressed cluster\n");
+ ret = -EIO;
+ goto fail;
+ }
+ cur_bytes = ret;
break;
@@ -1065,10 +1136,18 @@ static int __qcow_file_fmt_read_bvec(struct xloop_file_fmt *xlo_fmt, struct bio_
bvec_kunmap_irq(data, &irq_flags);
#endif
- if (len < 0)
- return len;
+ if (len < 0) {
+ dev_err(xloop_file_fmt_to_dev(xlo_fmt), "Read error in uncompressed cluster\n");
+ ret = len;
+ goto fail;
+ }
- ASSERT(len == cur_bytes);
+ if (len == 0) {
+ dev_err(xloop_file_fmt_to_dev(xlo_fmt), "Premature EOF when reading uncompressed cluster\n");
+ ret = -EIO;
+ goto fail;
+ }
+ cur_bytes = len;
break;
default:
diff --git a/src/kernel/xloop_file_fmt_qcow_main.h b/src/kernel/xloop_file_fmt_qcow_main.h
index 4556e3c..aff5e13 100644
--- a/src/kernel/xloop_file_fmt_qcow_main.h
+++ b/src/kernel/xloop_file_fmt_qcow_main.h
@@ -303,6 +303,7 @@ struct xloop_file_fmt_qcow_data {
/* used to cache last compressed QCOW cluster */
u8 *cmp_out_buf;
u64 cmp_last_coffset;
+ int cmp_last_size;
/*
* Compression type used for the image. Default: 0 - ZLIB
generated by cgit v1.2.3-55-g7522 (git 2.39.0) at 2024-11-21 17:00:55 +0100