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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>
This commit is contained in:
Daniel Borkmann 2015-05-06 16:12:29 +02:00 committed by David S. Miller
parent d9e12f42e5
commit 658da9379d
1 changed files with 6 additions and 3 deletions
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9
net/core/filter.c
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@ -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;