net/sched: taprio: extend minimum interval restriction to entire cycle too
[ Upstream commit fb66df20 ] It is possible for syzbot to side-step the restriction imposed by the blamed commit in the Fixes: tag, because the taprio UAPI permits a cycle-time different from (and potentially shorter than) the sum of entry intervals. We need one more restriction, which is that the cycle time itself must be larger than N * ETH_ZLEN bit times, where N is the number of schedule entries. This restriction needs to apply regardless of whether the cycle time came from the user or was the implicit, auto-calculated value, so we move the existing "cycle == 0" check outside the "if "(!new->cycle_time)" branch. This way covers both conditions and scenarios. Add a selftest which illustrates the issue triggered by syzbot. Fixes: b5b73b26 ("taprio: Fix allowing too small intervals") Reported-by:<syzbot+a7d2b1d5d1af83035567@syzkaller.appspotmail.com> Closes: https://lore.kernel.org/netdev/0000000000007d66bc06196e7c66@google.com/ Signed-off-by:
Vladimir Oltean <vladimir.oltean@nxp.com> Link: https://lore.kernel.org/r/20240527153955.553333-2-vladimir.oltean@nxp.com Signed-off-by:
Jakub Kicinski <kuba@kernel.org> Signed-off-by:
Sasha Levin <sashal@kernel.org>
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