Commit 658da937 authored May 06, 2015 by Daniel Borkmann Committed by David S. Miller May 09, 2015

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>

parent d9e12f42

net/core/filter.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -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;

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