c842a4c4ae
[ Upstream commit e0dc3b93bd7bcff8c3813d1df43e0908499c7cf0 ]
Strparser is reusing the qdisc_skb_cb struct to stash the skb message handling
progress, e.g. offset and length of the skb. First this is poorly named and
inherits a struct from qdisc that doesn't reflect the actual usage of cb[] at
this layer.
But, more importantly strparser is using the following to access its metadata.
(struct _strp_msg *)((void *)skb->cb + offsetof(struct qdisc_skb_cb, data))
Where _strp_msg is defined as:
struct _strp_msg {
struct strp_msg strp; /* 0 8 */
int accum_len; /* 8 4 */
/* size: 12, cachelines: 1, members: 2 */
/* last cacheline: 12 bytes */
};
So we use 12 bytes of ->data[] in struct. However in BPF code running parser
and verdict the user has read capabilities into the data[] array as well. Its
not too problematic, but we should not be exposing internal state to BPF
program. If its really needed then we can use the probe_read() APIs which allow
reading kernel memory. And I don't believe cb[] layer poses any API breakage by
moving this around because programs can't depend on cb[] across layers.
In order to fix another issue with a ctx rewrite we need to stash a temp
variable somewhere. To make this work cleanly this patch builds a cb struct
for sk_skb types called sk_skb_cb struct. Then we can use this consistently
in the strparser, sockmap space. Additionally we can start allowing ->cb[]
write access after this.
Fixes: 604326b41a ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Jussi Maki <joamaki@gmail.com>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20211103204736.248403-5-john.fastabend@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
160 lines
4.0 KiB
C
160 lines
4.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Stream Parser
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*
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* Copyright (c) 2016 Tom Herbert <tom@herbertland.com>
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*/
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#ifndef __NET_STRPARSER_H_
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#define __NET_STRPARSER_H_
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#define STRP_STATS_ADD(stat, count) ((stat) += (count))
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#define STRP_STATS_INCR(stat) ((stat)++)
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struct strp_stats {
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unsigned long long msgs;
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unsigned long long bytes;
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unsigned int mem_fail;
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unsigned int need_more_hdr;
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unsigned int msg_too_big;
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unsigned int msg_timeouts;
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unsigned int bad_hdr_len;
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};
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struct strp_aggr_stats {
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unsigned long long msgs;
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unsigned long long bytes;
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unsigned int mem_fail;
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unsigned int need_more_hdr;
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unsigned int msg_too_big;
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unsigned int msg_timeouts;
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unsigned int bad_hdr_len;
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unsigned int aborts;
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unsigned int interrupted;
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unsigned int unrecov_intr;
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};
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struct strparser;
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/* Callbacks are called with lock held for the attached socket */
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struct strp_callbacks {
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int (*parse_msg)(struct strparser *strp, struct sk_buff *skb);
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void (*rcv_msg)(struct strparser *strp, struct sk_buff *skb);
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int (*read_sock_done)(struct strparser *strp, int err);
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void (*abort_parser)(struct strparser *strp, int err);
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void (*lock)(struct strparser *strp);
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void (*unlock)(struct strparser *strp);
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};
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struct strp_msg {
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int full_len;
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int offset;
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};
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struct _strp_msg {
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/* Internal cb structure. struct strp_msg must be first for passing
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* to upper layer.
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*/
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struct strp_msg strp;
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int accum_len;
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};
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struct sk_skb_cb {
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#define SK_SKB_CB_PRIV_LEN 20
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unsigned char data[SK_SKB_CB_PRIV_LEN];
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struct _strp_msg strp;
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};
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static inline struct strp_msg *strp_msg(struct sk_buff *skb)
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{
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return (struct strp_msg *)((void *)skb->cb +
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offsetof(struct sk_skb_cb, strp));
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}
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/* Structure for an attached lower socket */
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struct strparser {
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struct sock *sk;
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u32 stopped : 1;
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u32 paused : 1;
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u32 aborted : 1;
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u32 interrupted : 1;
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u32 unrecov_intr : 1;
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struct sk_buff **skb_nextp;
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struct sk_buff *skb_head;
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unsigned int need_bytes;
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struct delayed_work msg_timer_work;
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struct work_struct work;
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struct strp_stats stats;
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struct strp_callbacks cb;
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};
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/* Must be called with lock held for attached socket */
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static inline void strp_pause(struct strparser *strp)
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{
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strp->paused = 1;
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}
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/* May be called without holding lock for attached socket */
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void strp_unpause(struct strparser *strp);
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/* Must be called with process lock held (lock_sock) */
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void __strp_unpause(struct strparser *strp);
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static inline void save_strp_stats(struct strparser *strp,
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struct strp_aggr_stats *agg_stats)
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{
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/* Save psock statistics in the mux when psock is being unattached. */
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#define SAVE_PSOCK_STATS(_stat) (agg_stats->_stat += \
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strp->stats._stat)
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SAVE_PSOCK_STATS(msgs);
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SAVE_PSOCK_STATS(bytes);
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SAVE_PSOCK_STATS(mem_fail);
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SAVE_PSOCK_STATS(need_more_hdr);
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SAVE_PSOCK_STATS(msg_too_big);
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SAVE_PSOCK_STATS(msg_timeouts);
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SAVE_PSOCK_STATS(bad_hdr_len);
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#undef SAVE_PSOCK_STATS
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if (strp->aborted)
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agg_stats->aborts++;
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if (strp->interrupted)
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agg_stats->interrupted++;
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if (strp->unrecov_intr)
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agg_stats->unrecov_intr++;
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}
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static inline void aggregate_strp_stats(struct strp_aggr_stats *stats,
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struct strp_aggr_stats *agg_stats)
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{
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#define SAVE_PSOCK_STATS(_stat) (agg_stats->_stat += stats->_stat)
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SAVE_PSOCK_STATS(msgs);
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SAVE_PSOCK_STATS(bytes);
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SAVE_PSOCK_STATS(mem_fail);
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SAVE_PSOCK_STATS(need_more_hdr);
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SAVE_PSOCK_STATS(msg_too_big);
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SAVE_PSOCK_STATS(msg_timeouts);
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SAVE_PSOCK_STATS(bad_hdr_len);
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SAVE_PSOCK_STATS(aborts);
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SAVE_PSOCK_STATS(interrupted);
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SAVE_PSOCK_STATS(unrecov_intr);
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#undef SAVE_PSOCK_STATS
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}
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void strp_done(struct strparser *strp);
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void strp_stop(struct strparser *strp);
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void strp_check_rcv(struct strparser *strp);
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int strp_init(struct strparser *strp, struct sock *sk,
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const struct strp_callbacks *cb);
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void strp_data_ready(struct strparser *strp);
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int strp_process(struct strparser *strp, struct sk_buff *orig_skb,
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unsigned int orig_offset, size_t orig_len,
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size_t max_msg_size, long timeo);
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#endif /* __NET_STRPARSER_H_ */
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