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| author | Eric Dumazet <edumazet@google.com> | 2024-10-08 14:31:10 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-11-14 13:15:17 +0100 |
| commit | a60db84f772fc3a906c6c4072f9207579c41166f (patch) | |
| tree | f9755d8f019c6d1bed8ac155609ee4b71c2f75a6 /net | |
| parent | 5cf45281a6ee768b77057cfad448569132e056cb (diff) | |
| download | linux-a60db84f772fc3a906c6c4072f9207579c41166f.tar.gz linux-a60db84f772fc3a906c6c4072f9207579c41166f.tar.bz2 linux-a60db84f772fc3a906c6c4072f9207579c41166f.zip | |
net: do not delay dst_entries_add() in dst_release()
commit ac888d58869bb99753e7652be19a151df9ecb35d upstream.
dst_entries_add() uses per-cpu data that might be freed at netns
dismantle from ip6_route_net_exit() calling dst_entries_destroy()
Before ip6_route_net_exit() can be called, we release all
the dsts associated with this netns, via calls to dst_release(),
which waits an rcu grace period before calling dst_destroy()
dst_entries_add() use in dst_destroy() is racy, because
dst_entries_destroy() could have been called already.
Decrementing the number of dsts must happen sooner.
Notes:
1) in CONFIG_XFRM case, dst_destroy() can call
dst_release_immediate(child), this might also cause UAF
if the child does not have DST_NOCOUNT set.
IPSEC maintainers might take a look and see how to address this.
2) There is also discussion about removing this count of dst,
which might happen in future kernels.
Fixes: f88649721268 ("ipv4: fix dst race in sk_dst_get()")
Closes: https://lore.kernel.org/lkml/CANn89iLCCGsP7SFn9HKpvnKu96Td4KD08xf7aGtiYgZnkjaL=w@mail.gmail.com/T/
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Xin Long <lucien.xin@gmail.com>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Link: https://patch.msgid.link/20241008143110.1064899-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
[ resolved conflict due to bc9d3a9f2afc ("net: dst: Switch to rcuref_t
reference counting") is not in the tree ]
Signed-off-by: Abdelkareem Abdelsaamad <kareemem@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/dst.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/net/core/dst.c b/net/core/dst.c index d178c564138e..8db87258d145 100644 --- a/net/core/dst.c +++ b/net/core/dst.c @@ -108,9 +108,6 @@ struct dst_entry *dst_destroy(struct dst_entry * dst) child = xdst->child; } #endif - if (!(dst->flags & DST_NOCOUNT)) - dst_entries_add(dst->ops, -1); - if (dst->ops->destroy) dst->ops->destroy(dst); netdev_put(dst->dev, &dst->dev_tracker); @@ -160,6 +157,12 @@ void dst_dev_put(struct dst_entry *dst) } EXPORT_SYMBOL(dst_dev_put); +static void dst_count_dec(struct dst_entry *dst) +{ + if (!(dst->flags & DST_NOCOUNT)) + dst_entries_add(dst->ops, -1); +} + void dst_release(struct dst_entry *dst) { if (dst) { @@ -169,8 +172,10 @@ void dst_release(struct dst_entry *dst) if (WARN_ONCE(newrefcnt < 0, "dst_release underflow")) net_warn_ratelimited("%s: dst:%p refcnt:%d\n", __func__, dst, newrefcnt); - if (!newrefcnt) + if (!newrefcnt){ + dst_count_dec(dst); call_rcu(&dst->rcu_head, dst_destroy_rcu); + } } } EXPORT_SYMBOL(dst_release); @@ -184,8 +189,10 @@ void dst_release_immediate(struct dst_entry *dst) if (WARN_ONCE(newrefcnt < 0, "dst_release_immediate underflow")) net_warn_ratelimited("%s: dst:%p refcnt:%d\n", __func__, dst, newrefcnt); - if (!newrefcnt) + if (!newrefcnt){ + dst_count_dec(dst); dst_destroy(dst); + } } } EXPORT_SYMBOL(dst_release_immediate); |