The commit is pushed to "branch-rh9-5.14.0-284.11.1.vz9.25.x-ovz" and will
appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh9-5.14.0-284.11.1.el9
------>
commit 80fb4fc5c303c94a0e565ef9b13fe664d3e3bcdb
Author: Kees Cook <[email protected]>
Date: Mon Dec 6 22:27:58 2021 -0800
ms/skbuff: Extract list pointers to silence compiler warnings
Under both -Warray-bounds and the object_size sanitizer, the compiler is
upset about accessing prev/next of sk_buff when the object it thinks it
is coming from is sk_buff_head. The warning is a false positive due to
the compiler taking a conservative approach, opting to warn at casting
time rather than access time.
However, in support of enabling -Warray-bounds globally (which has
found many real bugs), arrange things for sk_buff so that the compiler
can unambiguously see that there is no intention to access anything
except prev/next. Introduce and cast to a separate struct sk_buff_list,
which contains _only_ the first two fields, silencing the warnings:
In file included from ./include/net/net_namespace.h:39,
from ./include/linux/netdevice.h:37,
from net/core/netpoll.c:17:
net/core/netpoll.c: In function 'refill_skbs':
./include/linux/skbuff.h:2086:9: warning: array subscript 'struct
sk_buff[0]' is partly outside array bounds of 'struct sk_buff_head[1]'
[-Warray-bounds]
2086 | __skb_insert(newsk, next->prev, next, list);
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
net/core/netpoll.c:49:28: note: while referencing 'skb_pool'
49 | static struct sk_buff_head skb_pool;
| ^~~~~~~~
This change results in no executable instruction differences.
Signed-off-by: Kees Cook <[email protected]>
Link:
https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
(cherry picked from ms commit 1a2fb220edca98d18f90e3ef5bd6853a6b22b1b8)
Signed-off-by: Konstantin Khorenko <[email protected]>
Feature: fix ms/sock
---
include/linux/skbuff.h | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 5d9b35ff4720..2463e078e54a 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -296,9 +296,11 @@ struct tc_skb_ext {
#endif
struct sk_buff_head {
- /* These two members must be first. */
- struct sk_buff *next;
- struct sk_buff *prev;
+ /* These two members must be first to match sk_buff. */
+ struct_group_tagged(sk_buff_list, list,
+ struct sk_buff *next;
+ struct sk_buff *prev;
+ );
__u32 qlen;
spinlock_t lock;
@@ -733,7 +735,7 @@ typedef unsigned char *sk_buff_data_t;
struct sk_buff {
union {
struct {
- /* These two members must be first. */
+ /* These two members must be first to match
sk_buff_head. */
struct sk_buff *next;
struct sk_buff *prev;
@@ -2002,8 +2004,8 @@ static inline void __skb_insert(struct sk_buff *newsk,
*/
WRITE_ONCE(newsk->next, next);
WRITE_ONCE(newsk->prev, prev);
- WRITE_ONCE(next->prev, newsk);
- WRITE_ONCE(prev->next, newsk);
+ WRITE_ONCE(((struct sk_buff_list *)next)->prev, newsk);
+ WRITE_ONCE(((struct sk_buff_list *)prev)->next, newsk);
WRITE_ONCE(list->qlen, list->qlen + 1);
}
@@ -2099,7 +2101,7 @@ static inline void __skb_queue_after(struct sk_buff_head
*list,
struct sk_buff *prev,
struct sk_buff *newsk)
{
- __skb_insert(newsk, prev, prev->next, list);
+ __skb_insert(newsk, prev, ((struct sk_buff_list *)prev)->next, list);
}
void skb_append(struct sk_buff *old, struct sk_buff *newsk,
@@ -2109,7 +2111,7 @@ static inline void __skb_queue_before(struct sk_buff_head
*list,
struct sk_buff *next,
struct sk_buff *newsk)
{
- __skb_insert(newsk, next->prev, next, list);
+ __skb_insert(newsk, ((struct sk_buff_list *)next)->prev, next, list);
}
/**
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