diff options
| author | Ruitong Liu <cnitlrt@gmail.com> | 2026-02-14 01:59:48 +0800 |
|---|---|---|
| committer | Sasha Levin <sashal@kernel.org> | 2026-03-04 07:20:56 -0500 |
| commit | 59809fda4da7730cfe84a948033f47eb45db073d (patch) | |
| tree | c9b0805fa47bbeb563e06194f97529d08958f205 | |
| parent | 8320727be7ff704e07c87624efc2a4a75f54b3ce (diff) | |
net/sched: act_skbedit: fix divide-by-zero in tcf_skbedit_hash()
[ Upstream commit be054cc66f739a9ba615dba9012a07fab8e7dd6f ]
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>
Signed-off-by: Sasha Levin <sashal@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 7f598784fd30..0fcf40a5d1e3 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; @@ -189,6 +189,10 @@ 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) |