From: Saeed Mirzamohammadi saeed.mirzamohammadi@oracle.com
commit 31cc578ae2de19c748af06d859019dced68e325d upstream.
This patch fixes the issue due to:
BUG: KASAN: slab-out-of-bounds in nft_flow_rule_create+0x622/0x6a2 net/netfilter/nf_tables_offload.c:40 Read of size 8 at addr ffff888103910b58 by task syz-executor227/16244
The error happens when expr->ops is accessed early on before performing the boundary check and after nft_expr_next() moves the expr to go out-of-bounds.
This patch checks the boundary condition before expr->ops that fixes the slab-out-of-bounds Read issue.
Add nft_expr_more() and use it to fix this problem.
Signed-off-by: Saeed Mirzamohammadi saeed.mirzamohammadi@oracle.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- include/net/netfilter/nf_tables.h | 6 ++++++ net/netfilter/nf_tables_api.c | 6 +++--- net/netfilter/nf_tables_offload.c | 4 ++-- 3 files changed, 11 insertions(+), 5 deletions(-)
--- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -872,6 +872,12 @@ static inline struct nft_expr *nft_expr_ return (struct nft_expr *)&rule->data[rule->dlen]; }
+static inline bool nft_expr_more(const struct nft_rule *rule, + const struct nft_expr *expr) +{ + return expr != nft_expr_last(rule) && expr->ops; +} + static inline struct nft_userdata *nft_userdata(const struct nft_rule *rule) { return (void *)&rule->data[rule->dlen]; --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -254,7 +254,7 @@ static void nft_rule_expr_activate(const struct nft_expr *expr;
expr = nft_expr_first(rule); - while (expr != nft_expr_last(rule) && expr->ops) { + while (nft_expr_more(rule, expr)) { if (expr->ops->activate) expr->ops->activate(ctx, expr);
@@ -269,7 +269,7 @@ static void nft_rule_expr_deactivate(con struct nft_expr *expr;
expr = nft_expr_first(rule); - while (expr != nft_expr_last(rule) && expr->ops) { + while (nft_expr_more(rule, expr)) { if (expr->ops->deactivate) expr->ops->deactivate(ctx, expr, phase);
@@ -2642,7 +2642,7 @@ static void nf_tables_rule_destroy(const * is called on error from nf_tables_newrule(). */ expr = nft_expr_first(rule); - while (expr != nft_expr_last(rule) && expr->ops) { + while (nft_expr_more(rule, expr)) { next = nft_expr_next(expr); nf_tables_expr_destroy(ctx, expr); expr = next; --- a/net/netfilter/nf_tables_offload.c +++ b/net/netfilter/nf_tables_offload.c @@ -37,7 +37,7 @@ struct nft_flow_rule *nft_flow_rule_crea struct nft_expr *expr;
expr = nft_expr_first(rule); - while (expr->ops && expr != nft_expr_last(rule)) { + while (nft_expr_more(rule, expr)) { if (expr->ops->offload_flags & NFT_OFFLOAD_F_ACTION) num_actions++;
@@ -61,7 +61,7 @@ struct nft_flow_rule *nft_flow_rule_crea ctx->net = net; ctx->dep.type = NFT_OFFLOAD_DEP_UNSPEC;
- while (expr->ops && expr != nft_expr_last(rule)) { + while (nft_expr_more(rule, expr)) { if (!expr->ops->offload) { err = -EOPNOTSUPP; goto err_out;