From: Ilya Maximets Date: Wed, 9 Oct 2019 16:49:29 +0000 (+0200) Subject: libbpf: Fix passing uninitialized bytes to setsockopt X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=25bfef430e960e695403b5d9c8dcc11b9f5d62be;p=linux.git libbpf: Fix passing uninitialized bytes to setsockopt 'struct xdp_umem_reg' has 4 bytes of padding at the end that makes valgrind complain about passing uninitialized stack memory to the syscall: Syscall param socketcall.setsockopt() points to uninitialised byte(s) at 0x4E7AB7E: setsockopt (in /usr/lib64/libc-2.29.so) by 0x4BDE035: xsk_umem__create@@LIBBPF_0.0.4 (xsk.c:172) Uninitialised value was created by a stack allocation at 0x4BDDEBA: xsk_umem__create@@LIBBPF_0.0.4 (xsk.c:140) Padding bytes appeared after introducing of a new 'flags' field. memset() is required to clear them. Fixes: 10d30e301732 ("libbpf: add flags to umem config") Signed-off-by: Ilya Maximets Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20191009164929.17242-1-i.maximets@ovn.org --- diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c index 24fa313524fb2..b0f532544c91f 100644 --- a/tools/lib/bpf/xsk.c +++ b/tools/lib/bpf/xsk.c @@ -163,6 +163,7 @@ int xsk_umem__create_v0_0_4(struct xsk_umem **umem_ptr, void *umem_area, umem->umem_area = umem_area; xsk_set_umem_config(&umem->config, usr_config); + memset(&mr, 0, sizeof(mr)); mr.addr = (uintptr_t)umem_area; mr.len = size; mr.chunk_size = umem->config.frame_size;