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| author | Sabrina Dubroca <sd@queasysnail.net> | 2026-03-24 00:25:57 +0100 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-03-26 18:32:14 -0700 |
| commit | 629ec78ef8608d955ce217880cdc3e1873af3a15 (patch) | |
| tree | fafc0f4c05bbd7c1d5ca9823cd30df856511be63 /include | |
| parent | 45dbf8fcea4dcf28cabcf4a1778e908feadf4c90 (diff) | |
| download | lwn-629ec78ef8608d955ce217880cdc3e1873af3a15.tar.gz lwn-629ec78ef8608d955ce217880cdc3e1873af3a15.zip | |
mpls: add seqcount to protect the platform_label{,s} pair
The RCU-protected codepaths (mpls_forward, mpls_dump_routes) can have
an inconsistent view of platform_labels vs platform_label in case of a
concurrent resize (resize_platform_label_table, under
platform_mutex). This can lead to OOB accesses.
This patch adds a seqcount, so that we get a consistent snapshot.
Note that mpls_label_ok is also susceptible to this, so the check
against RTA_DST in rtm_to_route_config, done outside platform_mutex,
is not sufficient. This value gets passed to mpls_label_ok once more
in both mpls_route_add and mpls_route_del, so there is no issue, but
that additional check must not be removed.
Reported-by: Yuan Tan <tanyuan98@outlook.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Fixes: 7720c01f3f590 ("mpls: Add a sysctl to control the size of the mpls label table")
Fixes: dde1b38e873c ("mpls: Convert mpls_dump_routes() to RCU.")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Link: https://patch.msgid.link/cd8fca15e3eb7e212b094064cd83652e20fd9d31.1774284088.git.sd@queasysnail.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/net/netns/mpls.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/net/netns/mpls.h b/include/net/netns/mpls.h index 6682e51513ef..2073cbac2afb 100644 --- a/include/net/netns/mpls.h +++ b/include/net/netns/mpls.h @@ -17,6 +17,7 @@ struct netns_mpls { size_t platform_labels; struct mpls_route __rcu * __rcu *platform_label; struct mutex platform_mutex; + seqcount_mutex_t platform_label_seq; struct ctl_table_header *ctl; }; |