Denis Andzakovic discovered a potential use-after-free in older kernel
versions, using syzkaller. tcp_write_queue_purge() frees all skbs in
the TCP write queue and can leave sk->sk_send_head pointing to freed
memory. tcp_disconnect() clears that pointer after calling
tcp_write_queue_purge(), but tcp_connect() does not. It is
(surprisingly) possible to add to the write queue between
disconnection and reconnection, so this needs to be done in both
places.
This bug was introduced by backports of commit 7f582b248d0a ("tcp:
purge write queue in tcp_connect_init()") and does not exist upstream
because of earlier changes in commit 75c119afe14f ("tcp: implement
rb-tree based retransmit queue"). The latter is a major change that's
not suitable for stable.
Reported-by: Denis Andzakovic <denis.andzakovic(a)pulsesecurity.co.nz>
Bisected-by: Salvatore Bonaccorso <carnil(a)debian.org>
Fixes: 7f582b248d0a ("tcp: purge write queue in tcp_connect_init()")
Cc: <stable(a)vger.kernel.org> # before 4.15
Cc: Eric Dumazet <edumazet(a)google.com>
Signed-off-by: Ben Hutchings <ben(a)decadent.org.uk>
---
include/net/tcp.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/include/net/tcp.h b/include/net/tcp.h
index fed2a78fb8cb..f9b985d4d779 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1517,6 +1517,8 @@ struct tcp_fastopen_context {
struct rcu_head rcu;
};
+static inline void tcp_init_send_head(struct sock *sk);
+
/* write queue abstraction */
static inline void tcp_write_queue_purge(struct sock *sk)
{
@@ -1524,6 +1526,7 @@ static inline void tcp_write_queue_purge(struct sock *sk)
while ((skb = __skb_dequeue(&sk->sk_write_queue)) != NULL)
sk_wmem_free_skb(sk, skb);
+ tcp_init_send_head(sk);
sk_mem_reclaim(sk);
tcp_clear_all_retrans_hints(tcp_sk(sk));
inet_csk(sk)->icsk_backoff = 0;
THP splitting path is missing the split_page_owner() call that split_page()
has. As a result, split THP pages are wrongly reported in the page_owner file
as order-9 pages. Furthermore when the former head page is freed, the remaining
former tail pages are not listed in the page_owner file at all. This patch
fixes that by adding the split_page_owner() call into __split_huge_page().
Fixes: a9627bc5e34e ("mm/page_owner: introduce split_page_owner and replace manual handling")
Reported-by: Kirill A. Shutemov <kirill(a)shutemov.name>
Cc: stable(a)vger.kernel.org
Signed-off-by: Vlastimil Babka <vbabka(a)suse.cz>
---
mm/huge_memory.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 738065f765ab..de1f15969e27 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -32,6 +32,7 @@
#include <linux/shmem_fs.h>
#include <linux/oom.h>
#include <linux/numa.h>
+#include <linux/page_owner.h>
#include <asm/tlb.h>
#include <asm/pgalloc.h>
@@ -2516,6 +2517,9 @@ static void __split_huge_page(struct page *page, struct list_head *list,
}
ClearPageCompound(head);
+
+ split_page_owner(head, HPAGE_PMD_ORDER);
+
/* See comment in __split_huge_page_tail() */
if (PageAnon(head)) {
/* Additional pin to swap cache */
--
2.22.0
From: Ding Xiang <dingxiang(a)cmss.chinamobile.com>
In the error path of stm_source_register_device(), the kfree is
unnecessary, as the put_device() before it ends up calling
stm_source_device_release() to free stm_source_device, leading to
a double free at the outer kfree() call. Remove it.
Signed-off-by: Ding Xiang <dingxiang(a)cmss.chinamobile.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin(a)linux.intel.com>
Fixes: 7bd1d4093c2fa ("stm class: Introduce an abstraction for System Trace Module devices")
Link: https://lore.kernel.org/linux-arm-kernel/1563354988-23826-1-git-send-email-…
Cc: stable(a)vger.kernel.org # v4.4+
---
drivers/hwtracing/stm/core.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c
index e55b902560de..181e7ff1ec4f 100644
--- a/drivers/hwtracing/stm/core.c
+++ b/drivers/hwtracing/stm/core.c
@@ -1276,7 +1276,6 @@ int stm_source_register_device(struct device *parent,
err:
put_device(&src->dev);
- kfree(src);
return err;
}
--
2.23.0.rc1