qga: Fix undefined C behavior
The QAPI struct GuestFileWhence has a comment about how we are exploiting equivalent values between two different integer types shared in a union. But C says behavior is undefined on assignments to overlapping storage when the two types are not the same width, and indeed, 'int64_t value' and 'enum QGASeek name' are very likely to be different in width. Utilize a temporary variable to fix things. Reported-by: Peter Maydell <peter.maydell@linaro.org> Fixes:stable-4.20b4b49387
Fixes: Coverity CID 1421990 Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com> (cherry picked from commita23f38a729
) Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
parent
4996bd7161
commit
e3531619f1
|
@ -482,10 +482,15 @@ done:
|
|||
* the guest's SEEK_ constants. */
|
||||
int ga_parse_whence(GuestFileWhence *whence, Error **errp)
|
||||
{
|
||||
/* Exploit the fact that we picked values to match QGA_SEEK_*. */
|
||||
/*
|
||||
* Exploit the fact that we picked values to match QGA_SEEK_*;
|
||||
* however, we have to use a temporary variable since the union
|
||||
* members may have different size.
|
||||
*/
|
||||
if (whence->type == QTYPE_QSTRING) {
|
||||
int value = whence->u.name;
|
||||
whence->type = QTYPE_QNUM;
|
||||
whence->u.value = whence->u.name;
|
||||
whence->u.value = value;
|
||||
}
|
||||
switch (whence->u.value) {
|
||||
case QGA_SEEK_SET:
|
||||
|
|
Loading…
Reference in New Issue