From dd2e84bb3804103ad1c26a21deb4b35b0e166746 Mon Sep 17 00:00:00 2001 From: Alexander Lobakin Date: Fri, 28 Jul 2023 17:52:05 +0200 Subject: [PATCH] virtchnl: fix fake 1-elem arrays in structs allocated as `nents + 1` - 1 The two most problematic virtchnl structures are virtchnl_rss_key and virtchnl_rss_lut. Their "flex" arrays have the type of u8, thus, when allocating / checking, the actual size is calculated as `sizeof + nents - 1 byte`. But their sizeof() is not 1 byte larger than the size of such structure with proper flex array, it's two bytes larger due to the padding. That said, their size is always 1 byte larger unless there are no tail elements -- then it's +2 bytes. Add virtchnl_struct_size() macro which will handle this case (and later other cases as well). Make its calling conv the same as we call struct_size() to allow it to be drop-in, even though it's unlikely to become possible to switch to generic API. The macro will calculate a proper size of a structure with a flex array at the end, so that it becomes transparent for the compilers, but add the difference from the old values, so that the real size of sorta-ABI-messages doesn't change. Use it on the allocation side in IAVF and the receiving side (defined as static inline in virtchnl.h) for the mentioned two structures. Signed-off-by: Alexander Lobakin Reviewed-by: Kees Cook Tested-by: Rafal Romanowski Signed-off-by: Tony Nguyen --- .../net/ethernet/intel/iavf/iavf_virtchnl.c | 6 ++-- include/linux/avf/virtchnl.h | 31 ++++++++++++++----- 2 files changed, 25 insertions(+), 12 deletions(-) diff --git a/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c b/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c index be3c007ce90a..10f03054a603 100644 --- a/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c +++ b/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c @@ -1085,8 +1085,7 @@ void iavf_set_rss_key(struct iavf_adapter *adapter) adapter->current_op); return; } - len = sizeof(struct virtchnl_rss_key) + - (adapter->rss_key_size * sizeof(u8)) - 1; + len = virtchnl_struct_size(vrk, key, adapter->rss_key_size); vrk = kzalloc(len, GFP_KERNEL); if (!vrk) return; @@ -1117,8 +1116,7 @@ void iavf_set_rss_lut(struct iavf_adapter *adapter) adapter->current_op); return; } - len = sizeof(struct virtchnl_rss_lut) + - (adapter->rss_lut_size * sizeof(u8)) - 1; + len = virtchnl_struct_size(vrl, lut, adapter->rss_lut_size); vrl = kzalloc(len, GFP_KERNEL); if (!vrl) return; diff --git a/include/linux/avf/virtchnl.h b/include/linux/avf/virtchnl.h index c15221dcb75e..3ab207c14809 100644 --- a/include/linux/avf/virtchnl.h +++ b/include/linux/avf/virtchnl.h @@ -866,18 +866,20 @@ VIRTCHNL_CHECK_STRUCT_LEN(4, virtchnl_promisc_info); struct virtchnl_rss_key { u16 vsi_id; u16 key_len; - u8 key[1]; /* RSS hash key, packed bytes */ + u8 key[]; /* RSS hash key, packed bytes */ }; -VIRTCHNL_CHECK_STRUCT_LEN(6, virtchnl_rss_key); +VIRTCHNL_CHECK_STRUCT_LEN(4, virtchnl_rss_key); +#define virtchnl_rss_key_LEGACY_SIZEOF 6 struct virtchnl_rss_lut { u16 vsi_id; u16 lut_entries; - u8 lut[1]; /* RSS lookup table */ + u8 lut[]; /* RSS lookup table */ }; -VIRTCHNL_CHECK_STRUCT_LEN(6, virtchnl_rss_lut); +VIRTCHNL_CHECK_STRUCT_LEN(4, virtchnl_rss_lut); +#define virtchnl_rss_lut_LEGACY_SIZEOF 6 /* VIRTCHNL_OP_GET_RSS_HENA_CAPS * VIRTCHNL_OP_SET_RSS_HENA @@ -1367,6 +1369,17 @@ struct virtchnl_fdir_del { VIRTCHNL_CHECK_STRUCT_LEN(12, virtchnl_fdir_del); +#define __vss_byone(p, member, count, old) \ + (struct_size(p, member, count) + (old - 1 - struct_size(p, member, 0))) + +#define __vss(type, func, p, member, count) \ + struct type: func(p, member, count, type##_LEGACY_SIZEOF) + +#define virtchnl_struct_size(p, m, c) \ + _Generic(*p, \ + __vss(virtchnl_rss_key, __vss_byone, p, m, c), \ + __vss(virtchnl_rss_lut, __vss_byone, p, m, c)) + /** * virtchnl_vc_validate_vf_msg * @ver: Virtchnl version info @@ -1479,19 +1492,21 @@ virtchnl_vc_validate_vf_msg(struct virtchnl_version_info *ver, u32 v_opcode, } break; case VIRTCHNL_OP_CONFIG_RSS_KEY: - valid_len = sizeof(struct virtchnl_rss_key); + valid_len = virtchnl_rss_key_LEGACY_SIZEOF; if (msglen >= valid_len) { struct virtchnl_rss_key *vrk = (struct virtchnl_rss_key *)msg; - valid_len += vrk->key_len - 1; + valid_len = virtchnl_struct_size(vrk, key, + vrk->key_len); } break; case VIRTCHNL_OP_CONFIG_RSS_LUT: - valid_len = sizeof(struct virtchnl_rss_lut); + valid_len = virtchnl_rss_lut_LEGACY_SIZEOF; if (msglen >= valid_len) { struct virtchnl_rss_lut *vrl = (struct virtchnl_rss_lut *)msg; - valid_len += vrl->lut_entries - 1; + valid_len = virtchnl_struct_size(vrl, lut, + vrl->lut_entries); } break; case VIRTCHNL_OP_GET_RSS_HENA_CAPS: -- 2.20.1