diff options
| author | Daniel Borkmann <daniel@iogearbox.net> | 2016-05-18 14:14:28 +0200 |
|---|---|---|
| committer | Michael Bestas <mkbestas@lineageos.org> | 2022-04-19 00:50:18 +0300 |
| commit | 2627bc364215f2647bb1f8e1fa2440ed691aae9d (patch) | |
| tree | 6bd9fb7ff81d623065e2555924af5ba60265d6d5 /kernel/bpf/core.c | |
| parent | 918b55bfd3cb60f705c68466996f7c30597185de (diff) | |
bpf: rather use get_random_int for randomizations
Start address randomization and blinding in BPF currently use
prandom_u32(). prandom_u32() values are not exposed to unpriviledged
user space to my knowledge, but given other kernel facilities such as
ASLR, stack canaries, etc make use of stronger get_random_int(), we
better make use of it here as well given blinding requests successively
new random values. get_random_int() has minimal entropy pool depletion,
is not cryptographically secure, but doesn't need to be for our use
cases here.
Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Chatur27 <jasonbright2709@gmail.com>
Diffstat (limited to 'kernel/bpf/core.c')
| -rw-r--r-- | kernel/bpf/core.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index f1e8a0def99b..b94a36550591 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -231,7 +231,7 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, hdr->pages = size / PAGE_SIZE; hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)), PAGE_SIZE - sizeof(*hdr)); - start = (prandom_u32() % hole) & ~(alignment - 1); + start = (get_random_int() % hole) & ~(alignment - 1); /* Leave a random number of instructions before BPF code. */ *image_ptr = &hdr->image[start]; @@ -251,7 +251,7 @@ static int bpf_jit_blind_insn(const struct bpf_insn *from, struct bpf_insn *to_buff) { struct bpf_insn *to = to_buff; - u32 imm_rnd = prandom_u32(); + u32 imm_rnd = get_random_int(); s16 off; BUILD_BUG_ON(BPF_REG_AX + 1 != MAX_BPF_JIT_REG); |