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authorRichard Henderson <richard.henderson@linaro.org>2019-03-14 15:37:43 -0700
committerRichard Henderson <richard.henderson@linaro.org>2019-05-22 12:38:54 -0400
commitf7b2502cdc2eeb458a4490c1b8f4a83c07d46219 (patch)
tree3612248269e460c43bb21733e3c6d0ca671fabaa
parent4347e6383f17ae6b70af833b165862f9f338b0b9 (diff)
ui/vnc: Use gcrypto_random_bytes for start_auth_vnc
Use a better interface for random numbers than rand(). Fail gracefully if for some reason we cannot use the crypto system. Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com> Reviewed-by: Gerd Hoffmann <kraxel@redhat.com> Reviewed-by: Daniel P. Berrangé <berrange@redhat.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
-rw-r--r--ui/vnc.c22
1 files changed, 11 insertions, 11 deletions
diff --git a/ui/vnc.c b/ui/vnc.c
index 785edf3af1..d83f4a6ff9 100644
--- a/ui/vnc.c
+++ b/ui/vnc.c
@@ -43,6 +43,7 @@
#include "crypto/hash.h"
#include "crypto/tlscredsanon.h"
#include "crypto/tlscredsx509.h"
+#include "crypto/random.h"
#include "qom/object_interfaces.h"
#include "qemu/cutils.h"
#include "io/dns-resolver.h"
@@ -2547,16 +2548,6 @@ static void authentication_failed(VncState *vs)
vnc_client_error(vs);
}
-static void make_challenge(VncState *vs)
-{
- int i;
-
- srand(time(NULL)+getpid()+getpid()*987654+rand());
-
- for (i = 0 ; i < sizeof(vs->challenge) ; i++)
- vs->challenge[i] = (int) (256.0*rand()/(RAND_MAX+1.0));
-}
-
static int protocol_client_auth_vnc(VncState *vs, uint8_t *data, size_t len)
{
unsigned char response[VNC_AUTH_CHALLENGE_SIZE];
@@ -2628,7 +2619,16 @@ reject:
void start_auth_vnc(VncState *vs)
{
- make_challenge(vs);
+ Error *err = NULL;
+
+ if (qcrypto_random_bytes(vs->challenge, sizeof(vs->challenge), &err)) {
+ trace_vnc_auth_fail(vs, vs->auth, "cannot get random bytes",
+ error_get_pretty(err));
+ error_free(err);
+ authentication_failed(vs);
+ return;
+ }
+
/* Send client a 'random' challenge */
vnc_write(vs, vs->challenge, sizeof(vs->challenge));
vnc_flush(vs);