From: Eric Dumazet Date: Wed, 22 Jul 2026 14:17:42 +0000 (+0000) Subject: drop_monitor: fix size calculations for 64-bit attributes X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=7089f7ab99c89f443c92d8fcc585e63f2727f0b3;p=thirdparty%2Fkernel%2Flinux.git drop_monitor: fix size calculations for 64-bit attributes net_dm_packet_report_fill() and net_dm_hw_packet_report_fill() use nla_put_u64_64bit() to append 64-bit attributes (NET_DM_ATTR_PC and NET_DM_ATTR_TIMESTAMP). On 32-bit architectures without CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, nla_put_u64_64bit() may append a 4-byte NET_DM_ATTR_PAD attribute for 64-bit alignment. However, net_dm_packet_report_size() and net_dm_hw_packet_report_size() used nla_total_size(sizeof(u64)) instead of nla_total_size_64bit(sizeof(u64)), budgeting 12 bytes instead of up to 16 bytes. This under-estimation of SKB size can lead to an skb_over_panic() when __nla_reserve() or skb_put() is subsequently called. Fix this by using nla_total_size_64bit(sizeof(u64)) in both size calculations. Fixes: ca30707dee2b ("drop_monitor: Add packet alert mode") Fixes: 5e58109b1ea4 ("drop_monitor: Add support for packet alert mode for hardware drops") Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260722141743.3266924-2-edumazet@google.com Signed-off-by: Jakub Kicinski --- diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c index b4d1ff2829b6..9abcdee8c76e 100644 --- a/net/core/drop_monitor.c +++ b/net/core/drop_monitor.c @@ -566,13 +566,13 @@ static size_t net_dm_packet_report_size(size_t payload_len) /* NET_DM_ATTR_ORIGIN */ nla_total_size(sizeof(u16)) + /* NET_DM_ATTR_PC */ - nla_total_size(sizeof(u64)) + + nla_total_size_64bit(sizeof(u64)) + /* NET_DM_ATTR_SYMBOL */ nla_total_size(NET_DM_MAX_SYMBOL_LEN + 1) + /* NET_DM_ATTR_IN_PORT */ net_dm_in_port_size() + /* NET_DM_ATTR_TIMESTAMP */ - nla_total_size(sizeof(u64)) + + nla_total_size_64bit(sizeof(u64)) + /* NET_DM_ATTR_ORIG_LEN */ nla_total_size(sizeof(u32)) + /* NET_DM_ATTR_PROTO */ @@ -766,7 +766,7 @@ net_dm_hw_packet_report_size(size_t payload_len, /* NET_DM_ATTR_FLOW_ACTION_COOKIE */ net_dm_flow_action_cookie_size(hw_metadata) + /* NET_DM_ATTR_TIMESTAMP */ - nla_total_size(sizeof(u64)) + + nla_total_size_64bit(sizeof(u64)) + /* NET_DM_ATTR_ORIG_LEN */ nla_total_size(sizeof(u32)) + /* NET_DM_ATTR_PROTO */