From f1986bf87b0709c95126fe196cf39e5b8c8453a1 Mon Sep 17 00:00:00 2001 From: Jakub Kicinski Date: Wed, 2 Sep 2026 20:26:08 -0700 Subject: [PATCH] eth: nfp: bound the ntuple rule dump by the caller's buffer size nfp_net_get_fs_loc() dumps every entry of nn->fs.list into rule_locs[] without consulting cmd->rule_cnt, which is how many entries the caller had room for. ETHTOOL_GRXCLSRLALL requires no CAP_NET_ADMIN and the ioctl sizes the buffer from the rule_cnt userspace passes in, so once an admin has installed flow steering rules any user can ask for fewer slots than there are rules and run off the end of the allocation. A rule_cnt of 0 leaves the buffer pointer NULL and the walk dereferences it. Bail out with -EMSGSIZE when the buffer fills up, the way the other ntuple capable drivers do, and report how many locations were filled so a shrinking rule list does not leave the caller reading stale slots. Reported-by: VEGA Fixes: 9eb03bb1c035 ("nfp: add ethtool flow steering callbacks") Reviewed-by: Joe Damato Link: https://patch.msgid.link/20260903032611.3000029-3-kuba@kernel.org Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c b/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c index a2a89d48e3ca..9419e1ed8466 100644 --- a/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c +++ b/drivers/net/ethernet/netronome/nfp/nfp_net_ethtool.c @@ -1421,7 +1421,8 @@ static int nfp_net_get_fs_rule(struct nfp_net *nn, struct ethtool_rxnfc *cmd) return -ENOENT; } -static int nfp_net_get_fs_loc(struct nfp_net *nn, u32 *rule_locs) +static int nfp_net_get_fs_loc(struct nfp_net *nn, struct ethtool_rxnfc *cmd, + u32 *rule_locs) { struct nfp_fs_entry *entry; u32 count = 0; @@ -1429,8 +1430,12 @@ static int nfp_net_get_fs_loc(struct nfp_net *nn, u32 *rule_locs) if (!(nn->cap_w1 & NFP_NET_CFG_CTRL_FLOW_STEER)) return -EOPNOTSUPP; - list_for_each_entry(entry, &nn->fs.list, node) + list_for_each_entry(entry, &nn->fs.list, node) { + if (count == cmd->rule_cnt) + return -EMSGSIZE; rule_locs[count++] = entry->loc; + } + cmd->rule_cnt = count; return 0; } @@ -1455,7 +1460,7 @@ static int nfp_net_get_rxnfc(struct net_device *netdev, return nfp_net_get_fs_rule(nn, cmd); case ETHTOOL_GRXCLSRLALL: cmd->data = NFP_FS_MAX_ENTRY; - return nfp_net_get_fs_loc(nn, rule_locs); + return nfp_net_get_fs_loc(nn, cmd, rule_locs); default: return -EOPNOTSUPP; }