net: filter: add __GFP_NOWARN flag for larger kmem allocs

When seccomp BPF was added, it was discussed to add __GFP_NOWARN
flag for their configuration path as f.e. up to 32K allocations are
more prone to fail under stress. As we're going to reuse BPF API,
add __GFP_NOWARN flags where larger kmalloc() and friends allocations
could fail.

It doesn't make much sense to pass around __GFP_NOWARN everywhere as
an extra argument only for seccomp while we just as well could run
into similar issues for socket filters, where it's not desired to
have a user application throw a WARN() due to allocation failure.

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Nicolas Schichan <nschichan@freebox.fr>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Kees Cook <keescook@chromium.org>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/filter.c b/net/core/filter.c
index f887084..45c015d 100644 (file)
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -371,7 +371,8 @@ static int bpf_convert_filter(struct sock_filter *prog, int len,
                return -EINVAL;
 
        if (new_prog) {
-               addrs = kcalloc(len, sizeof(*addrs), GFP_KERNEL);
+               addrs = kcalloc(len, sizeof(*addrs),
+                               GFP_KERNEL | __GFP_NOWARN);
                if (!addrs)
                        return -ENOMEM;
        }
@@ -839,7 +840,9 @@ static int bpf_prog_store_orig_filter(struct bpf_prog *fp,
 
        fkprog = fp->orig_prog;
        fkprog->len = fprog->len;
-       fkprog->filter = kmemdup(fp->insns, fsize, GFP_KERNEL);
+
+       fkprog->filter = kmemdup(fp->insns, fsize,
+                                GFP_KERNEL | __GFP_NOWARN);
        if (!fkprog->filter) {
                kfree(fp->orig_prog);
                return -ENOMEM;
@@ -941,7 +944,7 @@ static struct bpf_prog *bpf_migrate_filter(struct bpf_prog *fp)
         * pass. At this time, the user BPF is stored in fp->insns.
         */
        old_prog = kmemdup(fp->insns, old_len * sizeof(struct sock_filter),
-                          GFP_KERNEL);
+                          GFP_KERNEL | __GFP_NOWARN);
        if (!old_prog) {
                err = -ENOMEM;
                goto out_err;