Xin LongandGreg Kroah-Hartman ec3c2d59a1 sctp: hold socket lock when dumping endpoints in sctp_diag ...

[ Upstream commit 7d8297e26b ]

SCTP_DIAG endpoint dumping was traversing endpoint address lists without
holding lock_sock(), while those lists could change concurrently via
socket operations (e.g., bindx changes). This creates a race where
nla_reserve() counts addresses under RCU protection, but the subsequent
copy may see fewer entries, potentially leaking uninitialized memory to
userspace.

Fix this by:

- Taking a reference on each endpoint during hash traversal
- Moving socket operations (lock_sock()) outside read_lock_bh()
- Serializing address list access during dump
- Reworking sctp_for_each_endpoint() to support restart-based traversal
  with (net, pos) tracking

Also:

- Add WARN_ON_ONCE() for inconsistent address counts
- Fix idiag_states filtering for LISTEN vs association cases
- Skip dumping endpoints being freed (ep->base.dead)
- Move dump position tracking into iterator, removing cb->args[4] and
  its comment for sctp_ep_dump().,
- Update the comment for cb->args[4] and remove the comment for unused
  cb->args[5] for sctp_sock_dump().

Note: traversal is restart-based and may re-scan buckets multiple times,
but this is acceptable due to small bucket sizes and required to support
sleeping-safe callbacks.

This issue was reported by Nico Yip (@_cyeaa_) working with TrendAI Zero
Day Initiative.

Reported-by: Zero Day Initiative <zdi-disclosures@trendmicro.com>
Fixes: 8f840e47f1 ("sctp: add the sctp_diag.c file")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Link: https://patch.msgid.link/4c1b49ab87e0f7d552ebd8172b364b1994e913c9.1781552190.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

2026-07-24 15:54:49 +02:00

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auth.h

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checksum.h

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command.h

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constants.h

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sctp.h

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sm.h

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stream_interleave.h

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stream_sched.h

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structs.h

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tsnmap.h

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ulpevent.h

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ulpqueue.h

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