https://github.com/torvalds/linux
Revision a13b67c9a015c4e21601ef9aa4ec9c5d972df1b4 authored by Pedro Tammela on 17 October 2023, 14:36:02 UTC, committed by Jakub Kicinski on 19 October 2023, 01:08:28 UTC
Christian Theune says: I upgraded from 6.1.38 to 6.1.55 this morning and it broke my traffic shaping script, leaving me with a non-functional uplink on a remote router. A 'rt' curve cannot be used as a inner curve (parent class), but we were allowing such configurations since the qdisc was introduced. Such configurations would trigger a UAF as Budimir explains: The parent will have vttree_insert() called on it in init_vf(), but will not have vttree_remove() called on it in update_vf() because it does not have the HFSC_FSC flag set. The qdisc always assumes that inner classes have the HFSC_FSC flag set. This is by design as it doesn't make sense 'qdisc wise' for an 'rt' curve to be an inner curve. Budimir's original patch disallows users to add classes with a 'rt' parent, but this is too strict as it breaks users that have been using 'rt' as a inner class. Another approach, taken by this patch, is to upgrade the inner 'rt' into a 'sc', warning the user in the process. It avoids the UAF reported by Budimir while also being more permissive to bad scripts/users/code using 'rt' as a inner class. Users checking the `tc class ls [...]` or `tc class get [...]` dumps would observe the curve change and are potentially breaking with this change. v1->v2: https://lore.kernel.org/all/20231013151057.2611860-1-pctammela@mojatatu.com/ - Correct 'Fixes' tag and merge with revert (Jakub) Cc: Christian Theune <ct@flyingcircus.io> Cc: Budimir Markovic <markovicbudimir@gmail.com> Fixes: b3d26c5702c7 ("net/sched: sch_hfsc: Ensure inner classes have fsc curve") Signed-off-by: Pedro Tammela <pctammela@mojatatu.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> Link: https://lore.kernel.org/r/20231017143602.3191556-1-pctammela@mojatatu.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
1 parent 1f9f214
Tip revision: a13b67c9a015c4e21601ef9aa4ec9c5d972df1b4 authored by Pedro Tammela on 17 October 2023, 14:36:02 UTC
net/sched: sch_hfsc: upgrade 'rt' to 'sc' when it becomes a inner curve
net/sched: sch_hfsc: upgrade 'rt' to 'sc' when it becomes a inner curve
Tip revision: a13b67c
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Kbuild | -rw-r--r-- | 2.5 KB |
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MAINTAINERS | -rw-r--r-- | 709.6 KB |
Makefile | -rw-r--r-- | 65.9 KB |
README | -rw-r--r-- | 727 bytes |
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