From: Ilya Maximets i.maximets@samsung.com
[ Upstream commit decb705e01a5d325c9876b9674043cde4b54f0db ]
'channels.max_combined' initialized only on ioctl success and errno is only valid on ioctl failure.
The code doesn't produce any runtime issues, but makes memory sanitizers angry:
Conditional jump or move depends on uninitialised value(s) at 0x55C056F: xsk_get_max_queues (xsk.c:336) by 0x55C05B2: xsk_create_bpf_maps (xsk.c:354) by 0x55C089F: xsk_setup_xdp_prog (xsk.c:447) by 0x55C0E57: xsk_socket__create (xsk.c:601) Uninitialised value was created by a stack allocation at 0x55C04CD: xsk_get_max_queues (xsk.c:318)
Additionally fixed warning on uninitialized bytes in ioctl arguments:
Syscall param ioctl(SIOCETHTOOL) points to uninitialised byte(s) at 0x648D45B: ioctl (in /usr/lib64/libc-2.28.so) by 0x55C0546: xsk_get_max_queues (xsk.c:330) by 0x55C05B2: xsk_create_bpf_maps (xsk.c:354) by 0x55C089F: xsk_setup_xdp_prog (xsk.c:447) by 0x55C0E57: xsk_socket__create (xsk.c:601) Address 0x1ffefff378 is on thread 1's stack in frame #1, created by xsk_get_max_queues (xsk.c:318) Uninitialised value was created by a stack allocation at 0x55C04CD: xsk_get_max_queues (xsk.c:318)
CC: Magnus Karlsson magnus.karlsson@intel.com Fixes: 1cad07884239 ("libbpf: add support for using AF_XDP sockets") Signed-off-by: Ilya Maximets i.maximets@samsung.com Acked-by: Andrii Nakryiko andriin@fb.com Signed-off-by: Alexei Starovoitov ast@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- tools/lib/bpf/xsk.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index ca272c5b67f47..8e03b65830da0 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -327,15 +327,14 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk)
static int xsk_get_max_queues(struct xsk_socket *xsk) { - struct ethtool_channels channels; - struct ifreq ifr; + struct ethtool_channels channels = { .cmd = ETHTOOL_GCHANNELS }; + struct ifreq ifr = {}; int fd, err, ret;
fd = socket(AF_INET, SOCK_DGRAM, 0); if (fd < 0) return -errno;
- channels.cmd = ETHTOOL_GCHANNELS; ifr.ifr_data = (void *)&channels; strncpy(ifr.ifr_name, xsk->ifname, IFNAMSIZ - 1); ifr.ifr_name[IFNAMSIZ - 1] = '\0'; @@ -345,7 +344,7 @@ static int xsk_get_max_queues(struct xsk_socket *xsk) goto out; }
- if (channels.max_combined == 0 || errno == EOPNOTSUPP) + if (err || channels.max_combined == 0) /* If the device says it has no channels, then all traffic * is sent to a single stream, so max queues = 1. */