From: Peter Foley <pefo...@google.com>
e.g.
1109 15:16:20.151506 Uninitialized bytes in ioctl_common_pre at offset 0 inside
[0x7ffc516af9b8, 4)
1109 15:16:20.151659 ==588974==WARNING: MemorySanitizer:
use-of-uninitialized-value
1109 15:16:20.312923 #0 0x5639b88acb21 in tap_probe_vnet_hdr_len
third_party/qemu/net/tap-linux.c:183:9
1109 15:16:20.312952 #1 0x5639b88afd66 in net_tap_fd_init
third_party/qemu/net/tap.c:409:9
1109 15:16:20.312954 #2 0x5639b88b2d1b in net_init_tap_one
third_party/qemu/net/tap.c:681:19
1109 15:16:20.312956 #3 0x5639b88b16a8 in net_init_tap
third_party/qemu/net/tap.c:912:13
1109 15:16:20.312957 #4 0x5639b8890175 in net_client_init1
third_party/qemu/net/net.c:1110:9
1109 15:16:20.312958 #5 0x5639b888f912 in net_client_init
third_party/qemu/net/net.c:1208:15
1109 15:16:20.312960 #6 0x5639b8894aa5 in net_param_nic
third_party/qemu/net/net.c:1588:11
1109 15:16:20.312961 #7 0x5639b900cd18 in qemu_opts_foreach
third_party/qemu/util/qemu-option.c:1135:14
1109 15:16:20.312962 #8 0x5639b889393c in net_init_clients
third_party/qemu/net/net.c:1612:9
1109 15:16:20.312964 #9 0x5639b717aaf3 in qemu_create_late_backends
third_party/qemu/softmmu/vl.c:1962:5
1109 15:16:20.312965 #10 0x5639b717aaf3 in qemu_init
third_party/qemu/softmmu/vl.c:3694:5
1109 15:16:20.312967 #11 0x5639b71083b8 in main
third_party/qemu/softmmu/main.c:49:5
1109 15:16:20.312968 #12 0x7f464de1d8d2 in __libc_start_main
(/usr/grte/v5/lib64/libc.so.6+0x628d2)
1109 15:16:20.312969 #13 0x5639b6bbd389 in _start
/usr/grte/v5/debug-src/src/csu/../sysdeps/x86_64/start.S:120
1109 15:16:20.312970
1109 15:16:20.312975 Uninitialized value was stored to memory at
1109 15:16:20.313393 #0 0x5639b88acbee in tap_probe_vnet_hdr_len
third_party/qemu/net/tap-linux.c
1109 15:16:20.313396 #1 0x5639b88afd66 in net_tap_fd_init
third_party/qemu/net/tap.c:409:9
1109 15:16:20.313398 #2 0x5639b88b2d1b in net_init_tap_one
third_party/qemu/net/tap.c:681:19
1109 15:16:20.313399 #3 0x5639b88b16a8 in net_init_tap
third_party/qemu/net/tap.c:912:13
1109 15:16:20.313400 #4 0x5639b8890175 in net_client_init1
third_party/qemu/net/net.c:1110:9
1109 15:16:20.313401 #5 0x5639b888f912 in net_client_init
third_party/qemu/net/net.c:1208:15
1109 15:16:20.313403 #6 0x5639b8894aa5 in net_param_nic
third_party/qemu/net/net.c:1588:11
1109 15:16:20.313404 #7 0x5639b900cd18 in qemu_opts_foreach
third_party/qemu/util/qemu-option.c:1135:14
1109 15:16:20.313405 #8 0x5639b889393c in net_init_clients
third_party/qemu/net/net.c:1612:9
1109 15:16:20.313407 #9 0x5639b717aaf3 in qemu_create_late_backends
third_party/qemu/softmmu/vl.c:1962:5
1109 15:16:20.313408 #10 0x5639b717aaf3 in qemu_init
third_party/qemu/softmmu/vl.c:3694:5
1109 15:16:20.313409 #11 0x5639b71083b8 in main
third_party/qemu/softmmu/main.c:49:5
1109 15:16:20.313410 #12 0x7f464de1d8d2 in __libc_start_main
(/usr/grte/v5/lib64/libc.so.6+0x628d2)
1109 15:16:20.313412 #13 0x5639b6bbd389 in _start
/usr/grte/v5/debug-src/src/csu/../sysdeps/x86_64/start.S:120
1109 15:16:20.313413
1109 15:16:20.313417 Uninitialized value was stored to memory at
1109 15:16:20.313791 #0 0x5639b88affbd in net_tap_fd_init
third_party/qemu/net/tap.c:400:26
1109 15:16:20.313826 #1 0x5639b88b2d1b in net_init_tap_one
third_party/qemu/net/tap.c:681:19
1109 15:16:20.313829 #2 0x5639b88b16a8 in net_init_tap
third_party/qemu/net/tap.c:912:13
1109 15:16:20.313831 #3 0x5639b8890175 in net_client_init1
third_party/qemu/net/net.c:1110:9
1109 15:16:20.313836 #4 0x5639b888f912 in net_client_init
third_party/qemu/net/net.c:1208:15
1109 15:16:20.313838 #5 0x5639b8894aa5 in net_param_nic
third_party/qemu/net/net.c:1588:11
1109 15:16:20.313839 #6 0x5639b900cd18 in qemu_opts_foreach
third_party/qemu/util/qemu-option.c:1135:14
1109 15:16:20.313841 #7 0x5639b889393c in net_init_clients
third_party/qemu/net/net.c:1612:9
1109 15:16:20.313843 #8 0x5639b717aaf3 in qemu_create_late_backends
third_party/qemu/softmmu/vl.c:1962:5
1109 15:16:20.313844 #9 0x5639b717aaf3 in qemu_init
third_party/qemu/softmmu/vl.c:3694:5
1109 15:16:20.313845 #10 0x5639b71083b8 in main
third_party/qemu/softmmu/main.c:49:5
1109 15:16:20.313846 #11 0x7f464de1d8d2 in __libc_start_main
(/usr/grte/v5/lib64/libc.so.6+0x628d2)
1109 15:16:20.313847 #12 0x5639b6bbd389 in _start
/usr/grte/v5/debug-src/src/csu/../sysdeps/x86_64/start.S:120
1109 15:16:20.313849
1109 15:16:20.313851 Uninitialized value was created by an allocation of
'ifr' in the stack frame of function 'tap_probe_vnet_hdr'
1109 15:16:20.313855 #0 0x5639b88ac680 in tap_probe_vnet_hdr
third_party/qemu/net/tap-linux.c:151
1109 15:16:20.313856
1109 15:16:20.313878 SUMMARY: MemorySanitizer: use-of-uninitialized-value
third_party/qemu/net/tap-linux.c:183:9 in tap_probe_vnet_hdr_len
Fixes: dc69004c7d8 ("net: move tap_probe_vnet_hdr() to tap-linux.c")
Reviewed-by: Hao Wu <wuhao...@google.com>
Reviewed-by: Patrick Venture <vent...@google.com>
Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org>
Signed-off-by: Peter Foley <pefo...@google.com>
Signed-off-by: Jason Wang <jasow...@redhat.com>
---
net/tap-linux.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/tap-linux.c b/net/tap-linux.c
index 9584769..5e70b93 100644
--- a/net/tap-linux.c
+++ b/net/tap-linux.c
@@ -150,6 +150,7 @@ void tap_set_sndbuf(int fd, const NetdevTapOptions *tap,
Error **errp)
int tap_probe_vnet_hdr(int fd, Error **errp)
{
struct ifreq ifr;
+ memset(&ifr, 0, sizeof(ifr));
if (ioctl(fd, TUNGETIFF, &ifr) != 0) {
/* TUNGETIFF is available since kernel v2.6.27 */
--
2.7.4
