diff options
| author | Ruitong Liu <cnitlrt@gmail.com> | 2026-02-14 01:59:48 +0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-02-17 17:27:39 -0800 |
| commit | be054cc66f739a9ba615dba9012a07fab8e7dd6f (patch) | |
| tree | 5ccac5d63f717bdf0b0039d2f048719ed02e54fc | |
| parent | a07c33c6f2fc693bf9c67514fcc15d9d417f390d (diff) | |
net/sched: act_skbedit: fix divide-by-zero in tcf_skbedit_hash()
Commit 38a6f0865796 ("net: sched: support hash selecting tx queue")
added SKBEDIT_F_TXQ_SKBHASH support. The inclusive range size is
computed as:
mapping_mod = queue_mapping_max - queue_mapping + 1;
The range size can be 65536 when the requested range covers all possible
u16 queue IDs (e.g. queue_mapping=0 and queue_mapping_max=U16_MAX).
That value cannot be represented in a u16 and previously wrapped to 0,
so tcf_skbedit_hash() could trigger a divide-by-zero:
queue_mapping += skb_get_hash(skb) % params->mapping_mod;
Compute mapping_mod in a wider type and reject ranges larger than U16_MAX
to prevent params->mapping_mod from becoming 0 and avoid the crash.
Fixes: 38a6f0865796 ("net: sched: support hash selecting tx queue")
Cc: stable@vger.kernel.org # 6.12+
Signed-off-by: Ruitong Liu <cnitlrt@gmail.com>
Link: https://patch.msgid.link/20260213175948.1505257-1-cnitlrt@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/sched/act_skbedit.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/net/sched/act_skbedit.c b/net/sched/act_skbedit.c index 8c1d1554f657..5450c1293eb5 100644 --- a/net/sched/act_skbedit.c +++ b/net/sched/act_skbedit.c @@ -126,7 +126,7 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla, struct tcf_skbedit *d; u32 flags = 0, *priority = NULL, *mark = NULL, *mask = NULL; u16 *queue_mapping = NULL, *ptype = NULL; - u16 mapping_mod = 1; + u32 mapping_mod = 1; bool exists = false; int ret = 0, err; u32 index; @@ -194,6 +194,10 @@ static int tcf_skbedit_init(struct net *net, struct nlattr *nla, } mapping_mod = *queue_mapping_max - *queue_mapping + 1; + if (mapping_mod > U16_MAX) { + NL_SET_ERR_MSG_MOD(extack, "The range of queue_mapping is invalid."); + return -EINVAL; + } flags |= SKBEDIT_F_TXQ_SKBHASH; } if (*pure_flags & SKBEDIT_F_INHERITDSFIELD) |