diff options
| author | Kuniyuki Iwashima <kuniyu@google.com> | 2026-03-01 01:17:22 +0300 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-03-03 05:49:39 +0300 |
| commit | 2bd6c9d600d66497f5293dbb8ec61a5e80f13e64 (patch) | |
| tree | d459f9f2e0faa7408ca785a4a819a1b8a2b68a3d | |
| parent | 402a8111d7becb4220a94f5684edfbd5d4668ddb (diff) | |
| download | linux-2bd6c9d600d66497f5293dbb8ec61a5e80f13e64.tar.xz | |
ipmr: Use MAXVIFS in mroute_msgsize().
mroute_msgsize() calculates skb size needed for ipmr_fill_mroute().
The size differs based on mrt->maxvif.
We will drop RTNL for ipmr_rtm_getroute() and mrt->maxvif may
change under RCU.
To avoid -EMSGSIZE, let's calculate the size with the maximum
value of mrt->maxvif, MAXVIFS.
struct rtnexthop is 8 bytes and MAXVIFS is 32, so the maximum delta
is 256 bytes, which is small enough.
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260228221800.1082070-5-kuniyu@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/ipv4/ipmr.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index eecc79a835d1..9f2dd726affb 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -2510,7 +2510,7 @@ static int _ipmr_fill_mroute(struct mr_table *mrt, struct sk_buff *skb, cmd, flags); } -static size_t mroute_msgsize(bool unresolved, int maxvif) +static size_t mroute_msgsize(bool unresolved) { size_t len = NLMSG_ALIGN(sizeof(struct rtmsg)) @@ -2523,7 +2523,7 @@ static size_t mroute_msgsize(bool unresolved, int maxvif) len = len + nla_total_size(4) /* RTA_IIF */ + nla_total_size(0) /* RTA_MULTIPATH */ - + maxvif * NLA_ALIGN(sizeof(struct rtnexthop)) + + MAXVIFS * NLA_ALIGN(sizeof(struct rtnexthop)) /* RTA_MFC_STATS */ + nla_total_size_64bit(sizeof(struct rta_mfc_stats)) ; @@ -2538,8 +2538,7 @@ static void mroute_netlink_event(struct mr_table *mrt, struct mfc_cache *mfc, struct sk_buff *skb; int err = -ENOBUFS; - skb = nlmsg_new(mroute_msgsize(mfc->_c.mfc_parent >= MAXVIFS, - mrt->maxvif), + skb = nlmsg_new(mroute_msgsize(mfc->_c.mfc_parent >= MAXVIFS), GFP_ATOMIC); if (!skb) goto errout; @@ -2711,7 +2710,7 @@ static int ipmr_rtm_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, goto errout_free; } - skb = nlmsg_new(mroute_msgsize(false, mrt->maxvif), GFP_KERNEL); + skb = nlmsg_new(mroute_msgsize(false), GFP_KERNEL); if (!skb) { err = -ENOBUFS; goto errout_free; |