diff options
| author | Zijian Zhang <zijianzhang@bytedance.com> | 2024-11-06 22:25:19 +0000 |
|---|---|---|
| committer | Martin KaFai Lau <martin.lau@kernel.org> | 2024-11-06 16:01:53 -0800 |
| commit | 5d609ba262475db450ba69b8e8a557bd768ac07a (patch) | |
| tree | 74808609f30b5ff5386490d1a11549480913a61d | |
| parent | 15ab0548e3107665c34579ae523b2b6e7c22082a (diff) | |
bpf, sockmap: Several fixes to bpf_msg_pop_data
Several fixes to bpf_msg_pop_data,
1. In sk_msg_shift_left, we should put_page
2. if (len == 0), return early is better
3. pop the entire sk_msg (last == msg->sg.size) should be supported
4. Fix for the value of variable "a"
5. In sk_msg_shift_left, after shifting, i has already pointed to the next
element. Addtional sk_msg_iter_var_next may result in BUG.
Fixes: 7246d8ed4dcc ("bpf: helper to pop data from messages")
Signed-off-by: Zijian Zhang <zijianzhang@bytedance.com>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/r/20241106222520.527076-8-zijianzhang@bytedance.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
| -rw-r--r-- | net/core/filter.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index 255d58bae2a9..2fdba950b575 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -2904,8 +2904,10 @@ static const struct bpf_func_proto bpf_msg_push_data_proto = { static void sk_msg_shift_left(struct sk_msg *msg, int i) { + struct scatterlist *sge = sk_msg_elem(msg, i); int prev; + put_page(sg_page(sge)); do { prev = i; sk_msg_iter_var_next(i); @@ -2942,6 +2944,9 @@ BPF_CALL_4(bpf_msg_pop_data, struct sk_msg *, msg, u32, start, if (unlikely(flags)) return -EINVAL; + if (unlikely(len == 0)) + return 0; + /* First find the starting scatterlist element */ i = msg->sg.start; do { @@ -2954,7 +2959,7 @@ BPF_CALL_4(bpf_msg_pop_data, struct sk_msg *, msg, u32, start, } while (i != msg->sg.end); /* Bounds checks: start and pop must be inside message */ - if (start >= offset + l || last >= msg->sg.size) + if (start >= offset + l || last > msg->sg.size) return -EINVAL; space = MAX_MSG_FRAGS - sk_msg_elem_used(msg); @@ -2983,12 +2988,12 @@ BPF_CALL_4(bpf_msg_pop_data, struct sk_msg *, msg, u32, start, */ if (start != offset) { struct scatterlist *nsge, *sge = sk_msg_elem(msg, i); - int a = start; + int a = start - offset; int b = sge->length - pop - a; sk_msg_iter_var_next(i); - if (pop < sge->length - a) { + if (b > 0) { if (space) { sge->length = a; sk_msg_shift_right(msg, i); @@ -3007,7 +3012,6 @@ BPF_CALL_4(bpf_msg_pop_data, struct sk_msg *, msg, u32, start, if (unlikely(!page)) return -ENOMEM; - sge->length = a; orig = sg_page(sge); from = sg_virt(sge); to = page_address(page); @@ -3017,7 +3021,7 @@ BPF_CALL_4(bpf_msg_pop_data, struct sk_msg *, msg, u32, start, put_page(orig); } pop = 0; - } else if (pop >= sge->length - a) { + } else { pop -= (sge->length - a); sge->length = a; } @@ -3051,7 +3055,6 @@ BPF_CALL_4(bpf_msg_pop_data, struct sk_msg *, msg, u32, start, pop -= sge->length; sk_msg_shift_left(msg, i); } - sk_msg_iter_var_next(i); } sk_mem_uncharge(msg->sk, len - pop); |