* [PATCH AUTOSEL 5.10 41/46] net/rds: Avoid potential use after free in rds_send_remove_from_sock [not found] <20210412162401.314035-1-sashal@kernel.org> @ 2021-04-12 16:23 ` Sasha Levin 2021-04-19 8:49 ` Pavel Machek 0 siblings, 1 reply; 2+ messages in thread From: Sasha Levin @ 2021-04-12 16:23 UTC (permalink / raw) To: linux-kernel, stable Cc: Aditya Pakki, Santosh Shilimkar, David S . Miller, Sasha Levin, netdev, linux-rdma, rds-devel From: Aditya Pakki <pakki001@umn.edu> [ Upstream commit 0c85a7e87465f2d4cbc768e245f4f45b2f299b05 ] In case of rs failure in rds_send_remove_from_sock(), the 'rm' resource is freed and later under spinlock, causing potential use-after-free. Set the free pointer to NULL to avoid undefined behavior. Signed-off-by: Aditya Pakki <pakki001@umn.edu> Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org> --- net/rds/message.c | 1 + net/rds/send.c | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-) diff --git a/net/rds/message.c b/net/rds/message.c index 071a261fdaab..90ebcfe5fe3b 100644 --- a/net/rds/message.c +++ b/net/rds/message.c @@ -180,6 +180,7 @@ void rds_message_put(struct rds_message *rm) rds_message_purge(rm); kfree(rm); + rm = NULL; } } EXPORT_SYMBOL_GPL(rds_message_put); diff --git a/net/rds/send.c b/net/rds/send.c index 985d0b7713ac..fe5264b9d4b3 100644 --- a/net/rds/send.c +++ b/net/rds/send.c @@ -665,7 +665,7 @@ static void rds_send_remove_from_sock(struct list_head *messages, int status) unlock_and_drop: spin_unlock_irqrestore(&rm->m_rs_lock, flags); rds_message_put(rm); - if (was_on_sock) + if (was_on_sock && rm) rds_message_put(rm); } -- 2.30.2 ^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH AUTOSEL 5.10 41/46] net/rds: Avoid potential use after free in rds_send_remove_from_sock 2021-04-12 16:23 ` [PATCH AUTOSEL 5.10 41/46] net/rds: Avoid potential use after free in rds_send_remove_from_sock Sasha Levin @ 2021-04-19 8:49 ` Pavel Machek 0 siblings, 0 replies; 2+ messages in thread From: Pavel Machek @ 2021-04-19 8:49 UTC (permalink / raw) To: Sasha Levin Cc: linux-kernel, stable, Aditya Pakki, Santosh Shilimkar, David S . Miller, netdev, linux-rdma, rds-devel [-- Attachment #1: Type: text/plain, Size: 1254 bytes --] Hi! > From: Aditya Pakki <pakki001@umn.edu> > > [ Upstream commit 0c85a7e87465f2d4cbc768e245f4f45b2f299b05 ] > > In case of rs failure in rds_send_remove_from_sock(), the 'rm' resource > is freed and later under spinlock, causing potential use-after-free. > Set the free pointer to NULL to avoid undefined behavior. This patch is crazy. It adds dead code. > +++ b/net/rds/message.c > @@ -180,6 +180,7 @@ void rds_message_put(struct rds_message *rm) > rds_message_purge(rm); > > kfree(rm); > + rm = NULL; > } > } We are already exiting function, changing local variable has no effect. > +++ b/net/rds/send.c > @@ -665,7 +665,7 @@ static void rds_send_remove_from_sock(struct list_head *messages, int status) > unlock_and_drop: > spin_unlock_irqrestore(&rm->m_rs_lock, flags); > rds_message_put(rm); > - if (was_on_sock) > + if (was_on_sock && rm) > rds_message_put(rm); > } If rm was non-NULL calling first rds_message_put (and it was, otherwise we oopsed), it is still non-NULL in second test. Best regards, Pavel -- 'DENX Software Engineering GmbH, Managing Director: Wolfgang Denk' 'HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany' [-- Attachment #2: Digital signature --] [-- Type: application/pgp-signature, Size: 181 bytes --] ^ permalink raw reply [flat|nested] 2+ messages in thread
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