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| author | Aleksandr Nogikh <nogikh@google.com> | 2020-10-29 17:36:19 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2020-11-02 18:01:34 -0800 |
| commit | 6370cc3bbd8a0f9bf975b013781243ab147876c6 (patch) | |
| tree | 1d800ae66d7a5b639dd86a99532436150af97528 /net/core | |
| parent | b08e84da205023009c456bd7f33feb83c5191c60 (diff) | |
| download | linux-6370cc3bbd8a0f9bf975b013781243ab147876c6.tar.gz linux-6370cc3bbd8a0f9bf975b013781243ab147876c6.tar.bz2 linux-6370cc3bbd8a0f9bf975b013781243ab147876c6.zip | |
net: add kcov handle to skb extensions
Remote KCOV coverage collection enables coverage-guided fuzzing of the
code that is not reachable during normal system call execution. It is
especially helpful for fuzzing networking subsystems, where it is
common to perform packet handling in separate work queues even for the
packets that originated directly from the user space.
Enable coverage-guided frame injection by adding kcov remote handle to
skb extensions. Default initialization in __alloc_skb and
__build_skb_around ensures that no socket buffer that was generated
during a system call will be missed.
Code that is of interest and that performs packet processing should be
annotated with kcov_remote_start()/kcov_remote_stop().
An alternative approach is to determine kcov_handle solely on the
basis of the device/interface that received the specific socket
buffer. However, in this case it would be impossible to distinguish
between packets that originated during normal background network
processes or were intentionally injected from the user space.
Signed-off-by: Aleksandr Nogikh <nogikh@google.com>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/skbuff.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 1ba8f0163744..c5e6c0b83a92 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -249,6 +249,9 @@ struct sk_buff *__alloc_skb(unsigned int size, gfp_t gfp_mask, fclones->skb2.fclone = SKB_FCLONE_CLONE; } + + skb_set_kcov_handle(skb, kcov_common_handle()); + out: return skb; nodata: @@ -282,6 +285,8 @@ static struct sk_buff *__build_skb_around(struct sk_buff *skb, memset(shinfo, 0, offsetof(struct skb_shared_info, dataref)); atomic_set(&shinfo->dataref, 1); + skb_set_kcov_handle(skb, kcov_common_handle()); + return skb; } @@ -4203,6 +4208,9 @@ static const u8 skb_ext_type_len[] = { #if IS_ENABLED(CONFIG_MPTCP) [SKB_EXT_MPTCP] = SKB_EXT_CHUNKSIZEOF(struct mptcp_ext), #endif +#if IS_ENABLED(CONFIG_KCOV) + [SKB_EXT_KCOV_HANDLE] = SKB_EXT_CHUNKSIZEOF(u64), +#endif }; static __always_inline unsigned int skb_ext_total_length(void) @@ -4220,6 +4228,9 @@ static __always_inline unsigned int skb_ext_total_length(void) #if IS_ENABLED(CONFIG_MPTCP) skb_ext_type_len[SKB_EXT_MPTCP] + #endif +#if IS_ENABLED(CONFIG_KCOV) + skb_ext_type_len[SKB_EXT_KCOV_HANDLE] + +#endif 0; } |