| Message ID | 20201019172532.3906-1-saeed.mirzamohammadi@oracle.com |
|---|---|
| State | New |
| Headers | show |
| Series | [linux-5.9,1/1] net: netfilter: fix KASAN: slab-out-of-bounds Read in nft_flow_rule_create | expand |
On Mon, Oct 19, 2020 at 10:25:32AM -0700, saeed.mirzamohammadi@oracle.com wrote: > From: Saeed Mirzamohammadi <saeed.mirzamohammadi@oracle.com> > > 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. Thanks. I made a slight variant of your patch. I'm attaching it, it is also fixing the problem but it introduced nft_expr_more() and use it everywhere. Let me know if this looks fine to you. From 3f60e5f489ec44e8b0a7e9e622c93be4df335fb6 Mon Sep 17 00:00:00 2001 From: Saeed Mirzamohammadi <saeed.mirzamohammadi@oracle.com> Date: Tue, 20 Oct 2020 13:41:36 +0200 Subject: [PATCH nf] netfilter: fix KASAN: slab-out-of-bounds Read in nft_flow_rule_create 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> --- 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(-) diff --git a/include/net/netfilter/nf_tables.h b/include/net/netfilter/nf_tables.h index 3f7e56b1171e..55b4cadf290a 100644 --- a/include/net/netfilter/nf_tables.h +++ b/include/net/netfilter/nf_tables.h @@ -891,6 +891,12 @@ static inline struct nft_expr *nft_expr_last(const struct nft_rule *rule) 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]; diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 9957e0ed8658..65cb8e3c13d9 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -302,7 +302,7 @@ static void nft_rule_expr_activate(const struct nft_ctx *ctx, 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); @@ -317,7 +317,7 @@ static void nft_rule_expr_deactivate(const struct nft_ctx *ctx, 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); @@ -3080,7 +3080,7 @@ static void nf_tables_rule_destroy(const struct nft_ctx *ctx, * 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; diff --git a/net/netfilter/nf_tables_offload.c b/net/netfilter/nf_tables_offload.c index 7c7e06624dc3..9f625724a20f 100644 --- 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_create(struct net *net, 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_create(struct net *net, 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; -- 2.20.1
Thanks! Yes, that looks good to me. Saeed > On Oct 20, 2020, at 4:50 AM, Pablo Neira Ayuso <pablo@netfilter.org> wrote: > > On Mon, Oct 19, 2020 at 10:25:32AM -0700, saeed.mirzamohammadi@oracle.com wrote: >> From: Saeed Mirzamohammadi <saeed.mirzamohammadi@oracle.com> >> >> 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. > > Thanks. I made a slight variant of your patch. > > I'm attaching it, it is also fixing the problem but it introduced > nft_expr_more() and use it everywhere. > > Let me know if this looks fine to you. > <0001-netfilter-fix-KASAN-slab-out-of-bounds-Read-in-nft_f.patch>
Attached the syzkaller C repro. Tested-by: Saeed Mirzamohammadi <saeed.mirzamohammadi@oracle.com> > On Oct 20, 2020, at 9:45 AM, Saeed Mirzamohammadi <saeed.mirzamohammadi@oracle.com> wrote: > > Thanks! Yes, that looks good to me. > > Saeed > >> On Oct 20, 2020, at 4:50 AM, Pablo Neira Ayuso <pablo@netfilter.org> wrote: >> >> On Mon, Oct 19, 2020 at 10:25:32AM -0700, saeed.mirzamohammadi@oracle.com wrote: >>> From: Saeed Mirzamohammadi <saeed.mirzamohammadi@oracle.com> >>> >>> 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. >> >> Thanks. I made a slight variant of your patch. >> >> I'm attaching it, it is also fixing the problem but it introduced >> nft_expr_more() and use it everywhere. >> >> Let me know if this looks fine to you. >> <0001-netfilter-fix-KASAN-slab-out-of-bounds-Read-in-nft_f.patch> >
On Sun, Oct 25, 2020 at 04:31:57PM -0700, Saeed Mirzamohammadi wrote:
> Adding stable.
What did that do?
confused,
greg k-h
On Tue, Oct 27, 2020 at 09:19:22AM +0100, Pablo Neira Ayuso wrote: > Hi Greg, > > On Tue, Oct 27, 2020 at 07:21:11AM +0100, Greg KH wrote: > > On Sun, Oct 25, 2020 at 04:31:57PM -0700, Saeed Mirzamohammadi wrote: > > > Adding stable. > > > > What did that do? > > Saeed is requesting that stable maintainers cherry-picks this patch: > > 31cc578ae2de ("netfilter: nftables_offload: KASAN slab-out-of-bounds > Read in nft_flow_rule_create") > > into stable 5.4 and 5.8. 5.9 is also a stable kernel :) Will go queue it up everywhere... thanks, greg k-h
On Thu, Oct 29, 2020 at 12:02:41PM +0100, Greg KH wrote: > On Tue, Oct 27, 2020 at 09:19:22AM +0100, Pablo Neira Ayuso wrote: > > Hi Greg, > > > > On Tue, Oct 27, 2020 at 07:21:11AM +0100, Greg KH wrote: > > > On Sun, Oct 25, 2020 at 04:31:57PM -0700, Saeed Mirzamohammadi wrote: > > > > Adding stable. > > > > > > What did that do? > > > > Saeed is requesting that stable maintainers cherry-picks this patch: > > > > 31cc578ae2de ("netfilter: nftables_offload: KASAN slab-out-of-bounds > > Read in nft_flow_rule_create") > > > > into stable 5.4 and 5.8. > > 5.9 is also a stable kernel :) Oh, indeed, I forgot this one :) > Will go queue it up everywhere... Thanks.
diff --git a/net/netfilter/nf_tables_offload.c b/net/netfilter/nf_tables_offload.c index 9ef37c1b7b3b..1273e3c0d4b8 100644 --- 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_create(struct net *net, struct nft_expr *expr; expr = nft_expr_first(rule); - while (expr->ops && expr != nft_expr_last(rule)) { + while (expr != nft_expr_last(rule) && expr->ops) { if (expr->ops->offload_flags & NFT_OFFLOAD_F_ACTION) num_actions++; @@ -61,7 +61,7 @@ struct nft_flow_rule *nft_flow_rule_create(struct net *net, ctx->net = net; ctx->dep.type = NFT_OFFLOAD_DEP_UNSPEC; - while (expr->ops && expr != nft_expr_last(rule)) { + while (expr != nft_expr_last(rule) && expr->ops) { if (!expr->ops->offload) { err = -EOPNOTSUPP; goto err_out;