* Eric Blake (ebl...@redhat.com) wrote: > Assigning strlen() to a uint32_t and then asserting that it isn't too > large doesn't catch the case of an input string 4G in length. > Thankfully, the incoming string can never be that large: if the export > name is reflecting what the client asked about, we already guarantee > that we drop the NBD connection if the client tries to send more than > 32M in a single NBD_OPT_* request; and if the export name is coming > from qemu, nbd_receive_negotiate() asserted that strlen(info->name) <= > NBD_MAX_STRING_SIZE. Still, it doesn't hurt to be more explicit in > how we write our assertion that we are aware that no wraparound is > possible. > > Fixes: 93676c88 ("nbd: Don't send oversize strings", v4.2.0) > Reported-by: Dr. David Alan Gilbert <dgilb...@redhat.com> > Signed-off-by: Eric Blake <ebl...@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilb...@redhat.com> > --- > nbd/client.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/nbd/client.c b/nbd/client.c > index 60c9f4941a..b601ee97e5 100644 > --- a/nbd/client.c > +++ b/nbd/client.c > @@ -658,7 +658,7 @@ static int nbd_send_meta_query(QIOChannel *ioc, uint32_t > opt, > char *p; > > data_len = sizeof(export_len) + export_len + sizeof(queries); > - assert(export_len <= NBD_MAX_STRING_SIZE); > + assert(strlen(export) <= NBD_MAX_STRING_SIZE); > if (query) { > query_len = strlen(query); > data_len += sizeof(query_len) + query_len; > -- > 2.37.3 > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK