| Message ID | c1fc68054ca34a028a46598c2cca98137be68295.1570482718.git.crobinso@redhat.com |
|---|---|
| State | Accepted |
| Commit | 16fffd8257230ccf8c1f5dbb373314b49b5fe3bc |
| Headers | show |
| Series | storagefile, security: qcow2 data_file support | expand |
On 10/7/19 6:49 PM, Cole Robinson wrote: > This is a step towards making this qcow2GetBackingStoreFormat into > a generic qcow2 extensions parser > > Signed-off-by: Cole Robinson <crobinso@redhat.com> > --- Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com> > src/util/virstoragefile.c | 66 +++++++++++++++++++++------------------ > 1 file changed, 35 insertions(+), 31 deletions(-) > > diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c > index 4a3c9df7a2..b8f7faf580 100644 > --- a/src/util/virstoragefile.c > +++ b/src/util/virstoragefile.c > @@ -429,11 +429,11 @@ cowGetBackingStore(char **res, > static int > qcow2GetBackingStoreFormat(int *format, > const char *buf, > - size_t buf_size, > - size_t extension_end) > + size_t buf_size) > { > size_t offset; > size_t extension_start; > + size_t extension_end; > int version = virReadBufInt32BE(buf + QCOWX_HDR_VERSION); > > if (version < 2) { > @@ -447,6 +447,37 @@ qcow2GetBackingStoreFormat(int *format, > else > extension_start = virReadBufInt32BE(buf + QCOW2v3_HDR_SIZE); > > + /* > + * Traditionally QCow2 files had a layout of > + * > + * [header] > + * [backingStoreName] > + * > + * Although the backingStoreName typically followed > + * the header immediately, this was not required by > + * the format. By specifying a higher byte offset for > + * the backing file offset in the header, it was > + * possible to leave space between the header and > + * start of backingStore. > + * > + * This hack is now used to store extensions to the > + * qcow2 format: > + * > + * [header] > + * [extensions] > + * [backingStoreName] > + * > + * Thus the file region to search for extensions is > + * between the end of the header (QCOW2_HDR_TOTAL_SIZE) > + * and the start of the backingStoreName (offset) > + * > + * for qcow2 v3 images, the length of the header > + * is stored at QCOW2v3_HDR_SIZE > + */ > + extension_end = virReadBufInt64BE(buf + QCOWX_HDR_BACKING_FILE_OFFSET); > + if (extension_end > buf_size) > + return -1; > + > /* > * The extensions take format of > * > @@ -506,6 +537,7 @@ qcowXGetBackingStore(char **res, > > if (buf_size < QCOWX_HDR_BACKING_FILE_OFFSET+8+4) > return BACKING_STORE_INVALID; > + > offset = virReadBufInt64BE(buf + QCOWX_HDR_BACKING_FILE_OFFSET); > if (offset > buf_size) > return BACKING_STORE_INVALID; > @@ -529,35 +561,7 @@ qcowXGetBackingStore(char **res, > memcpy(*res, buf + offset, size); > (*res)[size] = '\0'; > > - /* > - * Traditionally QCow2 files had a layout of > - * > - * [header] > - * [backingStoreName] > - * > - * Although the backingStoreName typically followed > - * the header immediately, this was not required by > - * the format. By specifying a higher byte offset for > - * the backing file offset in the header, it was > - * possible to leave space between the header and > - * start of backingStore. > - * > - * This hack is now used to store extensions to the > - * qcow2 format: > - * > - * [header] > - * [extensions] > - * [backingStoreName] > - * > - * Thus the file region to search for extensions is > - * between the end of the header (QCOW2_HDR_TOTAL_SIZE) > - * and the start of the backingStoreName (offset) > - * > - * for qcow2 v3 images, the length of the header > - * is stored at QCOW2v3_HDR_SIZE > - */ > - > - if (qcow2GetBackingStoreFormat(format, buf, buf_size, offset) < 0) > + if (qcow2GetBackingStoreFormat(format, buf, buf_size) < 0) > return BACKING_STORE_INVALID; > > return BACKING_STORE_OK; -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
diff --git a/src/util/virstoragefile.c b/src/util/virstoragefile.c index 4a3c9df7a2..b8f7faf580 100644 --- a/src/util/virstoragefile.c +++ b/src/util/virstoragefile.c @@ -429,11 +429,11 @@ cowGetBackingStore(char **res, static int qcow2GetBackingStoreFormat(int *format, const char *buf, - size_t buf_size, - size_t extension_end) + size_t buf_size) { size_t offset; size_t extension_start; + size_t extension_end; int version = virReadBufInt32BE(buf + QCOWX_HDR_VERSION); if (version < 2) { @@ -447,6 +447,37 @@ qcow2GetBackingStoreFormat(int *format, else extension_start = virReadBufInt32BE(buf + QCOW2v3_HDR_SIZE); + /* + * Traditionally QCow2 files had a layout of + * + * [header] + * [backingStoreName] + * + * Although the backingStoreName typically followed + * the header immediately, this was not required by + * the format. By specifying a higher byte offset for + * the backing file offset in the header, it was + * possible to leave space between the header and + * start of backingStore. + * + * This hack is now used to store extensions to the + * qcow2 format: + * + * [header] + * [extensions] + * [backingStoreName] + * + * Thus the file region to search for extensions is + * between the end of the header (QCOW2_HDR_TOTAL_SIZE) + * and the start of the backingStoreName (offset) + * + * for qcow2 v3 images, the length of the header + * is stored at QCOW2v3_HDR_SIZE + */ + extension_end = virReadBufInt64BE(buf + QCOWX_HDR_BACKING_FILE_OFFSET); + if (extension_end > buf_size) + return -1; + /* * The extensions take format of * @@ -506,6 +537,7 @@ qcowXGetBackingStore(char **res, if (buf_size < QCOWX_HDR_BACKING_FILE_OFFSET+8+4) return BACKING_STORE_INVALID; + offset = virReadBufInt64BE(buf + QCOWX_HDR_BACKING_FILE_OFFSET); if (offset > buf_size) return BACKING_STORE_INVALID; @@ -529,35 +561,7 @@ qcowXGetBackingStore(char **res, memcpy(*res, buf + offset, size); (*res)[size] = '\0'; - /* - * Traditionally QCow2 files had a layout of - * - * [header] - * [backingStoreName] - * - * Although the backingStoreName typically followed - * the header immediately, this was not required by - * the format. By specifying a higher byte offset for - * the backing file offset in the header, it was - * possible to leave space between the header and - * start of backingStore. - * - * This hack is now used to store extensions to the - * qcow2 format: - * - * [header] - * [extensions] - * [backingStoreName] - * - * Thus the file region to search for extensions is - * between the end of the header (QCOW2_HDR_TOTAL_SIZE) - * and the start of the backingStoreName (offset) - * - * for qcow2 v3 images, the length of the header - * is stored at QCOW2v3_HDR_SIZE - */ - - if (qcow2GetBackingStoreFormat(format, buf, buf_size, offset) < 0) + if (qcow2GetBackingStoreFormat(format, buf, buf_size) < 0) return BACKING_STORE_INVALID; return BACKING_STORE_OK;
This is a step towards making this qcow2GetBackingStoreFormat into a generic qcow2 extensions parser Signed-off-by: Cole Robinson <crobinso@redhat.com> --- src/util/virstoragefile.c | 66 +++++++++++++++++++++------------------ 1 file changed, 35 insertions(+), 31 deletions(-) -- 2.23.0 -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list