Описание
In the Linux kernel, the following vulnerability has been resolved:
net: ipv6: flowlabel: defer exclusive option free until RCU teardown
ip6fl_seq_show() walks the global flowlabel hash under the seq-file
RCU read-side lock and prints fl->opt->opt_nflen when an option block
is present.
Exclusive flowlabels currently free fl->opt as soon as fl->users
drops to zero in fl_release(). However, the surrounding
struct ip6_flowlabel remains visible in the global hash table until
later garbage collection removes it and fl_free_rcu() finally tears it
down.
A concurrent /proc/net/ip6_flowlabel reader can therefore race that
early kfree() and dereference freed option state, triggering a crash
in ip6fl_seq_show().
Fix this by keeping fl->opt alive until fl_free_rcu(). That matches
the lifetime already required for the enclosing flowlabel while readers
can still reach it under RCU.
In the Linux kernel, the following vulnerability has been resolved:
net: ipv6: flowlabel: defer exclusive option free until RCU teardown
ip6fl_seq_show() walks the global flowlabel hash under the seq-file
RCU read-side lock and prints fl->opt->opt_nflen when an option block
is present.
Exclusive flowlabels currently free fl->opt as soon as fl->users
drops to zero in fl_release(). However, the surrounding
struct ip6_flowlabel remains visible in the global hash table until
later garbage collection removes it and fl_free_rcu() finally tears it
down.
A concurrent /proc/net/ip6_flowlabel reader can therefore race that
early kfree() and dereference freed option state, triggering a crash
in ip6fl_seq_show().
Fix this by keeping fl->opt alive until fl_free_rcu(). That matches
the lifetime already required for the enclosing flowlabel while readers
can still reach it under RCU.
Ссылки
- https://nvd.nist.gov/vuln/detail/CVE-2026-31680
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
- https://git.kernel.org/stable/c/3c54b66c83fb8fcbde8e6a7bf90b65856e39f827
- https://git.kernel.org/stable/c/414726b69921fe6355ae453f5b35e68dd078342a
- https://git.kernel.org/stable/c/4b6798024f7b2d535f3db1002c760143cdbd1bd3
- https://git.kernel.org/stable/c/572ce62778519a7d4d1c15f55dd2e45a474133c4
- https://git.kernel.org/stable/c/5a6b15f861b7c1304949e3350d23490a5fe429fd
- https://git.kernel.org/stable/c/6c7fbdb8ffde6413640de7cfbd7c976c353e89f8
- https://git.kernel.org/stable/c/8027964931785cb73d520ac70a342a3dc16c249b
- https://git.kernel.org/stable/c/9ca562bb8e66978b53028fa32b1a190708e6a091
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: net: ipv6: flowlabel: defer exclusive option free until RCU teardown `ip6fl_seq_show()` walks the global flowlabel hash under the seq-file RCU read-side lock and prints `fl->opt->opt_nflen` when an option block is present. Exclusive flowlabels currently free `fl->opt` as soon as `fl->users` drops to zero in `fl_release()`. However, the surrounding `struct ip6_flowlabel` remains visible in the global hash table until later garbage collection removes it and `fl_free_rcu()` finally tears it down. A concurrent `/proc/net/ip6_flowlabel` reader can therefore race that early `kfree()` and dereference freed option state, triggering a crash in `ip6fl_seq_show()`. Fix this by keeping `fl->opt` alive until `fl_free_rcu()`. That matches the lifetime already required for the enclosing flowlabel while readers can still reach it under RCU.
In the Linux kernel, the following vulnerability has been resolved: net: ipv6: flowlabel: defer exclusive option free until RCU teardown `ip6fl_seq_show()` walks the global flowlabel hash under the seq-file RCU read-side lock and prints `fl->opt->opt_nflen` when an option block is present. Exclusive flowlabels currently free `fl->opt` as soon as `fl->users` drops to zero in `fl_release()`. However, the surrounding `struct ip6_flowlabel` remains visible in the global hash table until later garbage collection removes it and `fl_free_rcu()` finally tears it down. A concurrent `/proc/net/ip6_flowlabel` reader can therefore race that early `kfree()` and dereference freed option state, triggering a crash in `ip6fl_seq_show()`. Fix this by keeping `fl->opt` alive until `fl_free_rcu()`. That matches the lifetime already required for the enclosing flowlabel while readers can still reach it under RCU.
In the Linux kernel, the following vulnerability has been resolved: net: ipv6: flowlabel: defer exclusive option free until RCU teardown `ip6fl_seq_show()` walks the global flowlabel hash under the seq-file RCU read-side lock and prints `fl->opt->opt_nflen` when an option block is present. Exclusive flowlabels currently free `fl->opt` as soon as `fl->users` drops to zero in `fl_release()`. However, the surrounding `struct ip6_flowlabel` remains visible in the global hash table until later garbage collection removes it and `fl_free_rcu()` finally tears it down. A concurrent `/proc/net/ip6_flowlabel` reader can therefore race that early `kfree()` and dereference freed option state, triggering a crash in `ip6fl_seq_show()`. Fix this by keeping `fl->opt` alive until `fl_free_rcu()`. That matches the lifetime already required for the enclosing flowlabel while readers can still reach it under RCU.
net: ipv6: flowlabel: defer exclusive option free until RCU teardown
In the Linux kernel, the following vulnerability has been resolved: n ...