[PATCH OLK-5.10] net: fix crash when config small gso_max_size/gso_ipv4_max_size - Kernel

27 Nov 2024

mainline inclusion
from mainline-v6.12-rc6
commit 9ab5cf19fb0e4680f95e506d6c544259bf1111c4
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IB37AK
CVE: CVE-2024-50258
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
--------------------------------
Config a small gso_max_size/gso_ipv4_max_size will lead to an underflow
in sk_dst_gso_max_size(), which may trigger a BUG_ON crash,
because sk->sk_gso_max_size would be much bigger than device limits.
Call Trace:
tcp_write_xmit
    tso_segs = tcp_init_tso_segs(skb, mss_now);
        tcp_set_skb_tso_segs
            tcp_skb_pcount_set
                // skb->len = 524288, mss_now = 8
                // u16 tso_segs = 524288/8 = 65535 -> 0
                tso_segs = DIV_ROUND_UP(skb->len, mss_now)
    BUG_ON(!tso_segs)
Add check for the minimum value of gso_max_size and gso_ipv4_max_size.
Fixes: 46e6b992c250 ("rtnetlink: allow GSO maximums to be set on device creation")
Signed-off-by: Wang Liang wangliang74@huawei.com
Reviewed-by: Eric Dumazet edumazet@google.com
Link: https://patch.msgid.link/20241023035213.517386-1-wangliang74@huawei.com
Signed-off-by: Jakub Kicinski kuba@kernel.org
Conflicts:
        net/core/rtnetlink.c
[conflicts due to not mergered 7e4a51319d3a ("net: introduce nla_policy for IFLA_NEW_IFINDEX"),
conflicts due to not mergered 9eefedd58ae1 ("net: add gso_ipv4_max_size and gro_ipv4_max_size per device")]
Signed-off-by: Wang Liang wangliang74@huawei.com
---
 net/core/rtnetlink.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index fc2466b1b656..21d11f5b9af3 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -1864,7 +1864,7 @@ static const struct nla_policy ifla_policy[IFLA_MAX+1] = {
    [IFLA_NUM_TX_QUEUES]	= { .type = NLA_U32 },
    [IFLA_NUM_RX_QUEUES]	= { .type = NLA_U32 },
    [IFLA_GSO_MAX_SEGS]	= { .type = NLA_U32 },
-	[IFLA_GSO_MAX_SIZE]	= { .type = NLA_U32 },
+	[IFLA_GSO_MAX_SIZE]	= NLA_POLICY_MIN(NLA_U32, MAX_TCP_HEADER + 1),
    [IFLA_PHYS_PORT_ID]	= { .type = NLA_BINARY, .len = MAX_PHYS_ITEM_ID_LEN },
    [IFLA_CARRIER_CHANGES]	= { .type = NLA_U32 },  /* ignored */
    [IFLA_PHYS_SWITCH_ID]	= { .type = NLA_BINARY, .len = MAX_PHYS_ITEM_ID_LEN },
-- 
2.34.1


    