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[RFC,1/1] net: kcm: Use sk_psock size for kcm_psock_cache

Message ID 20220713063204.6294-2-khalid.masum.92@gmail.com
State New
Headers show
Series Fix KASAN: slab-out-of-bounds Read in sk_psock_get | expand

Commit Message

Khalid Masum July 13, 2022, 6:32 a.m. UTC
`struct sock` has a member `sk_user_data`, which got its memory allocated
in `kcm_attach` by `kcm_psock_cache` with the size of `kcm_psock`. Which
is not enough when the member is used as `sk_psock` causing out of bound
read.

Use `sk_psock` size to allocate memory instead for `sk_user_data`.

Reported-by: syzbot+1fa91bcd05206ff8cbb5@syzkaller.appspotmail.com
Signed-off-by: Khalid Masum <khalid.masum.92@gmail.com>
---
 net/kcm/kcmsock.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
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Patch

diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index 71899e5a5a11..688bee56f90c 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -23,6 +23,7 @@ 
 #include <linux/workqueue.h>
 #include <linux/syscalls.h>
 #include <linux/sched/signal.h>
+#include <linux/skmsg.h>
 
 #include <net/kcm.h>
 #include <net/netns/generic.h>
@@ -2041,7 +2042,7 @@  static int __init kcm_init(void)
 		goto fail;
 
 	kcm_psockp = kmem_cache_create("kcm_psock_cache",
-				       sizeof(struct kcm_psock), 0,
+				       sizeof(struct sk_psock), 0,
 					SLAB_HWCACHE_ALIGN, NULL);
 	if (!kcm_psockp)
 		goto fail;