diff options
| author | Jesper Dangaard Brouer <brouer@redhat.com> | 2023-02-03 13:59:29 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-02-06 09:56:38 +0000 |
| commit | 9dde0cd3b10f63bc4100ebadc7e32275baabfa68 (patch) | |
| tree | 08f48b41359f74ea3e8b1af884de2cc21d5aa9c4 | |
| parent | 149e8fb06cd925c38cfeb14458480be0cbe3a099 (diff) | |
net: introduce skb_poison_list and use in kfree_skb_list
First user of skb_poison_list is in kfree_skb_list_reason, to catch bugs
earlier like introduced in commit eedade12f4cb ("net: kfree_skb_list use
kmem_cache_free_bulk"). For completeness mentioned bug have been fixed in
commit f72ff8b81ebc ("net: fix kfree_skb_list use of skb_mark_not_on_list").
In case of a bug like mentioned commit we would have seen OOPS with:
general protection fault, probably for non-canonical address 0xdead000000000870
And content of one the registers e.g. R13: dead000000000800
In this case skb->len is at offset 112 bytes (0x70) why fault happens at
0x800+0x70 = 0x870
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/linux/poison.h | 3 | ||||
| -rw-r--r-- | include/linux/skbuff.h | 7 | ||||
| -rw-r--r-- | net/core/skbuff.c | 4 |
3 files changed, 13 insertions, 1 deletions
diff --git a/include/linux/poison.h b/include/linux/poison.h index 2d3249eb0e62..2823f90fdab4 100644 --- a/include/linux/poison.h +++ b/include/linux/poison.h @@ -81,6 +81,9 @@ /********** net/core/page_pool.c **********/ #define PP_SIGNATURE (0x40 + POISON_POINTER_DELTA) +/********** net/core/skbuff.c **********/ +#define SKB_LIST_POISON_NEXT ((void *)(0x800 + POISON_POINTER_DELTA)) + /********** kernel/bpf/ **********/ #define BPF_PTR_POISON ((void *)(0xeB9FUL + POISON_POINTER_DELTA)) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 5ba12185f43e..1fa95b916342 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -1738,6 +1738,13 @@ static inline void skb_mark_not_on_list(struct sk_buff *skb) skb->next = NULL; } +static inline void skb_poison_list(struct sk_buff *skb) +{ +#ifdef CONFIG_DEBUG_NET + skb->next = SKB_LIST_POISON_NEXT; +#endif +} + /* Iterate through singly-linked GSO fragments of an skb. */ #define skb_list_walk_safe(first, skb, next_skb) \ for ((skb) = (first), (next_skb) = (skb) ? (skb)->next : NULL; (skb); \ diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 44a19805c355..624e9e4ec116 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1000,8 +1000,10 @@ kfree_skb_list_reason(struct sk_buff *segs, enum skb_drop_reason reason) while (segs) { struct sk_buff *next = segs->next; - if (__kfree_skb_reason(segs, reason)) + if (__kfree_skb_reason(segs, reason)) { + skb_poison_list(segs); kfree_skb_add_bulk(segs, &sa, reason); + } segs = next; } |