[PATCH 1/1] netfilter: ipset: Fix oversized kvmalloc() calls

[Jozsef Kadlecsik]

The commit 

commit 7661809d493b426e979f39ab512e3adf41fbcc69
Author: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Date:   Wed Jul 14 09:45:49 2021 -0700

    mm: don't allow oversized kvmalloc() calls

limits the max allocatable memory via kvmalloc() to MAX_INT. Apply the
same limit in ipset.

Reported-by: syzbot+3493b1873fb3ea827986@xxxxxxxxxxxxxxxxxxxxxxxxx
Reported-by: syzbot+2b8443c35458a617c904@xxxxxxxxxxxxxxxxxxxxxxxxx
Reported-by: syzbot+ee5cb15f4a0e85e0d54e@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxx>
---
 net/netfilter/ipset/ip_set_hash_gen.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/ipset/ip_set_hash_gen.h b/net/netfilter/ipset/ip_set_hash_gen.h
index 6186358eac7c..6e391308431d 100644
--- a/net/netfilter/ipset/ip_set_hash_gen.h
+++ b/net/netfilter/ipset/ip_set_hash_gen.h
@@ -130,11 +130,11 @@ htable_size(u8 hbits)
 {
 	size_t hsize;
 
-	/* We must fit both into u32 in jhash and size_t */
+	/* We must fit both into u32 in jhash and INT_MAX in kvmalloc_node() */
 	if (hbits > 31)
 		return 0;
 	hsize = jhash_size(hbits);
-	if ((((size_t)-1) - sizeof(struct htable)) / sizeof(struct hbucket *)
+	if ((INT_MAX - sizeof(struct htable)) / sizeof(struct hbucket *)
 	    < hsize)
 		return 0;
 
-- 
2.20.1

Best regards,
Jozsef
-
E-mail  : kadlec@xxxxxxxxxxxxxxxxx, kadlecsik.jozsef@xxxxxxxxx
PGP key : https://wigner.hu/~kadlec/pgp_public_key.txt
Address : Wigner Research Centre for Physics
          H-1525 Budapest 114, POB. 49, Hungary