[PATCH net 7/7] netfilter: nftables: clone set element expression template
From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: 2021-04-12 22:31:19
Also in:
netfilter-devel
Subsystem:
netfilter, networking [general], the rest · Maintainers:
Pablo Neira Ayuso, Florian Westphal, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
memcpy() breaks when using connlimit in set elements. Use
nft_expr_clone() to initialize the connlimit expression list, otherwise
connlimit garbage collector crashes when walking on the list head copy.
[ 493.064656] Workqueue: events_power_efficient nft_rhash_gc [nf_tables]
[ 493.064685] RIP: 0010:find_or_evict+0x5a/0x90 [nf_conncount]
[ 493.064694] Code: 2b 43 40 83 f8 01 77 0d 48 c7 c0 f5 ff ff ff 44 39 63 3c 75 df 83 6d 18 01 48 8b 43 08 48 89 de 48 8b 13 48 8b 3d ee 2f 00 00 <48> 89 42 08 48 89 10 48 b8 00 01 00 00 00 00 ad de 48 89 03 48 83
[ 493.064699] RSP: 0018:ffffc90000417dc0 EFLAGS: 00010297
[ 493.064704] RAX: 0000000000000000 RBX: ffff888134f38410 RCX: 0000000000000000
[ 493.064708] RDX: 0000000000000000 RSI: ffff888134f38410 RDI: ffff888100060cc0
[ 493.064711] RBP: ffff88812ce594a8 R08: ffff888134f38438 R09: 00000000ebb9025c
[ 493.064714] R10: ffffffff8219f838 R11: 0000000000000017 R12: 0000000000000001
[ 493.064718] R13: ffffffff82146740 R14: ffff888134f38410 R15: 0000000000000000
[ 493.064721] FS: 0000000000000000(0000) GS:ffff88840e440000(0000) knlGS:0000000000000000
[ 493.064725] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 493.064729] CR2: 0000000000000008 CR3: 00000001330aa002 CR4: 00000000001706e0
[ 493.064733] Call Trace:
[ 493.064737] nf_conncount_gc_list+0x8f/0x150 [nf_conncount]
[ 493.064746] nft_rhash_gc+0x106/0x390 [nf_tables]
Reported-by: Laura Garcia Liebana <redacted>
Fixes: 409444522976 ("netfilter: nf_tables: add elements with stateful expressions")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/nf_tables_api.c | 46 ++++++++++++++++++++++++++---------
1 file changed, 34 insertions(+), 12 deletions(-)
diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index f57f1a6ba96f..589d2f6978d3 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c@@ -5295,16 +5295,35 @@ int nft_set_elem_expr_clone(const struct nft_ctx *ctx, struct nft_set *set, return -ENOMEM; } -static void nft_set_elem_expr_setup(const struct nft_set_ext *ext, int i, - struct nft_expr *expr_array[]) +static int nft_set_elem_expr_setup(struct nft_ctx *ctx, + const struct nft_set_ext *ext, + struct nft_expr *expr_array[], + u32 num_exprs) { struct nft_set_elem_expr *elem_expr = nft_set_ext_expr(ext); - struct nft_expr *expr = nft_setelem_expr_at(elem_expr, elem_expr->size); + struct nft_expr *expr; + int i, err; + + for (i = 0; i < num_exprs; i++) { + expr = nft_setelem_expr_at(elem_expr, elem_expr->size); + err = nft_expr_clone(expr, expr_array[i]); + if (err < 0) + goto err_elem_expr_setup; + + elem_expr->size += expr_array[i]->ops->size; + nft_expr_destroy(ctx, expr_array[i]); + expr_array[i] = NULL; + } + + return 0; + +err_elem_expr_setup: + for (; i < num_exprs; i++) { + nft_expr_destroy(ctx, expr_array[i]); + expr_array[i] = NULL; + } - memcpy(expr, expr_array[i], expr_array[i]->ops->size); - elem_expr->size += expr_array[i]->ops->size; - kfree(expr_array[i]); - expr_array[i] = NULL; + return -ENOMEM; } static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set,
@@ -5556,12 +5575,15 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set, *nft_set_ext_obj(ext) = obj; obj->use++; } - for (i = 0; i < num_exprs; i++) - nft_set_elem_expr_setup(ext, i, expr_array); + err = nft_set_elem_expr_setup(ctx, ext, expr_array, num_exprs); + if (err < 0) + goto err_elem_expr; trans = nft_trans_elem_alloc(ctx, NFT_MSG_NEWSETELEM, set); - if (trans == NULL) - goto err_trans; + if (trans == NULL) { + err = -ENOMEM; + goto err_elem_expr; + } ext->genmask = nft_genmask_cur(ctx->net) | NFT_SET_ELEM_BUSY_MASK; err = set->ops->insert(ctx->net, set, &elem, &ext2);
@@ -5605,7 +5627,7 @@ static int nft_add_set_elem(struct nft_ctx *ctx, struct nft_set *set, set->ops->remove(ctx->net, set, &elem); err_element_clash: kfree(trans); -err_trans: +err_elem_expr: if (obj) obj->use--;
--
2.20.1