From ce59f9686e0eca19431571c7403394a6c36371e2 Mon Sep 17 00:00:00 2001 From: Stanislav Fomichev Date: Mon, 27 Nov 2023 11:03:13 -0800 Subject: xsk: Validate xsk_tx_metadata flags Accept only the flags that the kernel knows about to make sure we can extend this field in the future. Note that only in XDP_COPY mode we propagate the error signal back to the user (via sendmsg). For zerocopy mode we silently skip the metadata for the descriptors that have wrong flags (since we process the descriptors deep in the driver). Signed-off-by: Stanislav Fomichev Link: https://lore.kernel.org/r/20231127190319.1190813-8-sdf@google.com Signed-off-by: Alexei Starovoitov --- include/net/xdp_sock_drv.h | 23 ++++++++++++++++++++++- net/xdp/xsk.c | 4 ++++ 2 files changed, 26 insertions(+), 1 deletion(-) diff --git a/include/net/xdp_sock_drv.h b/include/net/xdp_sock_drv.h index e2558ac3e195..81e02de3f453 100644 --- a/include/net/xdp_sock_drv.h +++ b/include/net/xdp_sock_drv.h @@ -165,12 +165,28 @@ static inline void *xsk_buff_raw_get_data(struct xsk_buff_pool *pool, u64 addr) return xp_raw_get_data(pool, addr); } +#define XDP_TXMD_FLAGS_VALID ( \ + XDP_TXMD_FLAGS_TIMESTAMP | \ + XDP_TXMD_FLAGS_CHECKSUM | \ + 0) + +static inline bool xsk_buff_valid_tx_metadata(struct xsk_tx_metadata *meta) +{ + return !(meta->flags & ~XDP_TXMD_FLAGS_VALID); +} + static inline struct xsk_tx_metadata *xsk_buff_get_metadata(struct xsk_buff_pool *pool, u64 addr) { + struct xsk_tx_metadata *meta; + if (!pool->tx_metadata_len) return NULL; - return xp_raw_get_data(pool, addr) - pool->tx_metadata_len; + meta = xp_raw_get_data(pool, addr) - pool->tx_metadata_len; + if (unlikely(!xsk_buff_valid_tx_metadata(meta))) + return NULL; /* no way to signal the error to the user */ + + return meta; } static inline void xsk_buff_dma_sync_for_cpu(struct xdp_buff *xdp, struct xsk_buff_pool *pool) @@ -332,6 +348,11 @@ static inline void *xsk_buff_raw_get_data(struct xsk_buff_pool *pool, u64 addr) return NULL; } +static inline bool xsk_buff_valid_tx_metadata(struct xsk_tx_metadata *meta) +{ + return false; +} + static inline struct xsk_tx_metadata *xsk_buff_get_metadata(struct xsk_buff_pool *pool, u64 addr) { return NULL; diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index e83ade32f1fd..d66ba9d6154f 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -728,6 +728,10 @@ static struct sk_buff *xsk_build_skb(struct xdp_sock *xs, } meta = buffer - xs->pool->tx_metadata_len; + if (unlikely(!xsk_buff_valid_tx_metadata(meta))) { + err = -EINVAL; + goto free_err; + } if (meta->flags & XDP_TXMD_FLAGS_CHECKSUM) { if (unlikely(meta->request.csum_start + -- cgit