6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Nicolas Dichtel nicolas.dichtel@6wind.com
[ Upstream commit e622502c310f1069fd9f41cd38210553115f610a ]
The stacktrace was: [ 86.305548] BUG: kernel NULL pointer dereference, address: 0000000000000092 [ 86.306815] #PF: supervisor read access in kernel mode [ 86.307717] #PF: error_code(0x0000) - not-present page [ 86.308624] PGD 0 P4D 0 [ 86.309091] Oops: 0000 [#1] PREEMPT SMP NOPTI [ 86.309883] CPU: 2 PID: 3139 Comm: pimd Tainted: G U 6.8.0-6wind-knet #1 [ 86.311027] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.1-0-g0551a4be2c-prebuilt.qemu-project.org 04/01/2014 [ 86.312728] RIP: 0010:ip_mr_forward (/build/work/knet/net/ipv4/ipmr.c:1985) [ 86.313399] Code: f9 1f 0f 87 85 03 00 00 48 8d 04 5b 48 8d 04 83 49 8d 44 c5 00 48 8b 40 70 48 39 c2 0f 84 d9 00 00 00 49 8b 46 58 48 83 e0 fe <80> b8 92 00 00 00 00 0f 84 55 ff ff ff 49 83 47 38 01 45 85 e4 0f [ 86.316565] RSP: 0018:ffffad21c0583ae0 EFLAGS: 00010246 [ 86.317497] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 [ 86.318596] RDX: ffff9559cb46c000 RSI: 0000000000000000 RDI: 0000000000000000 [ 86.319627] RBP: ffffad21c0583b30 R08: 0000000000000000 R09: 0000000000000000 [ 86.320650] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 [ 86.321672] R13: ffff9559c093a000 R14: ffff9559cc00b800 R15: ffff9559c09c1d80 [ 86.322873] FS: 00007f85db661980(0000) GS:ffff955a79d00000(0000) knlGS:0000000000000000 [ 86.324291] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 86.325314] CR2: 0000000000000092 CR3: 000000002f13a000 CR4: 0000000000350ef0 [ 86.326589] Call Trace: [ 86.327036] <TASK> [ 86.327434] ? show_regs (/build/work/knet/arch/x86/kernel/dumpstack.c:479) [ 86.328049] ? __die (/build/work/knet/arch/x86/kernel/dumpstack.c:421 /build/work/knet/arch/x86/kernel/dumpstack.c:434) [ 86.328508] ? page_fault_oops (/build/work/knet/arch/x86/mm/fault.c:707) [ 86.329107] ? do_user_addr_fault (/build/work/knet/arch/x86/mm/fault.c:1264) [ 86.329756] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223) [ 86.330350] ? __irq_work_queue_local (/build/work/knet/kernel/irq_work.c:111 (discriminator 1)) [ 86.331013] ? exc_page_fault (/build/work/knet/./arch/x86/include/asm/paravirt.h:693 /build/work/knet/arch/x86/mm/fault.c:1515 /build/work/knet/arch/x86/mm/fault.c:1563) [ 86.331702] ? asm_exc_page_fault (/build/work/knet/./arch/x86/include/asm/idtentry.h:570) [ 86.332468] ? ip_mr_forward (/build/work/knet/net/ipv4/ipmr.c:1985) [ 86.333183] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223) [ 86.333920] ipmr_mfc_add (/build/work/knet/./include/linux/rcupdate.h:782 /build/work/knet/net/ipv4/ipmr.c:1009 /build/work/knet/net/ipv4/ipmr.c:1273) [ 86.334583] ? __pfx_ipmr_hash_cmp (/build/work/knet/net/ipv4/ipmr.c:363) [ 86.335357] ip_mroute_setsockopt (/build/work/knet/net/ipv4/ipmr.c:1470) [ 86.336135] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223) [ 86.336854] ? ip_mroute_setsockopt (/build/work/knet/net/ipv4/ipmr.c:1470) [ 86.337679] do_ip_setsockopt (/build/work/knet/net/ipv4/ip_sockglue.c:944) [ 86.338408] ? __pfx_unix_stream_read_actor (/build/work/knet/net/unix/af_unix.c:2862) [ 86.339232] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223) [ 86.339809] ? aa_sk_perm (/build/work/knet/security/apparmor/include/cred.h:153 /build/work/knet/security/apparmor/net.c:181) [ 86.340342] ip_setsockopt (/build/work/knet/net/ipv4/ip_sockglue.c:1415) [ 86.340859] raw_setsockopt (/build/work/knet/net/ipv4/raw.c:836) [ 86.341408] ? security_socket_setsockopt (/build/work/knet/security/security.c:4561 (discriminator 13)) [ 86.342116] sock_common_setsockopt (/build/work/knet/net/core/sock.c:3716) [ 86.342747] do_sock_setsockopt (/build/work/knet/net/socket.c:2313) [ 86.343363] __sys_setsockopt (/build/work/knet/./include/linux/file.h:32 /build/work/knet/net/socket.c:2336) [ 86.344020] __x64_sys_setsockopt (/build/work/knet/net/socket.c:2340) [ 86.344766] do_syscall_64 (/build/work/knet/arch/x86/entry/common.c:52 /build/work/knet/arch/x86/entry/common.c:83) [ 86.345433] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223) [ 86.346161] ? syscall_exit_work (/build/work/knet/./include/linux/audit.h:357 /build/work/knet/kernel/entry/common.c:160) [ 86.346938] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223) [ 86.347657] ? syscall_exit_to_user_mode (/build/work/knet/kernel/entry/common.c:215) [ 86.348538] ? srso_return_thunk (/build/work/knet/arch/x86/lib/retpoline.S:223) [ 86.349262] ? do_syscall_64 (/build/work/knet/./arch/x86/include/asm/cpufeature.h:171 /build/work/knet/arch/x86/entry/common.c:98) [ 86.349971] entry_SYSCALL_64_after_hwframe (/build/work/knet/arch/x86/entry/entry_64.S:129)
The original packet in ipmr_cache_report() may be queued and then forwarded with ip_mr_forward(). This last function has the assumption that the skb dst is set.
After the below commit, the skb dst is dropped by ipv4_pktinfo_prepare(), which causes the oops.
Fixes: bb7403655b3c ("ipmr: support IP_PKTINFO on cache report IGMP msg") Signed-off-by: Nicolas Dichtel nicolas.dichtel@6wind.com Reviewed-by: Eric Dumazet edumazet@google.com Link: https://lore.kernel.org/r/20240125141847.1931933-1-nicolas.dichtel@6wind.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/net/ip.h | 2 +- net/ipv4/ip_sockglue.c | 6 ++++-- net/ipv4/ipmr.c | 2 +- net/ipv4/raw.c | 2 +- net/ipv4/udp.c | 2 +- 5 files changed, 8 insertions(+), 6 deletions(-)
diff --git a/include/net/ip.h b/include/net/ip.h index 3489a1cca5e7..162cf2d2f841 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -758,7 +758,7 @@ int ip_options_rcv_srr(struct sk_buff *skb, struct net_device *dev); * Functions provided by ip_sockglue.c */
-void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb); +void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb, bool drop_dst); void ip_cmsg_recv_offset(struct msghdr *msg, struct sock *sk, struct sk_buff *skb, int tlen, int offset); int ip_cmsg_send(struct sock *sk, struct msghdr *msg, diff --git a/net/ipv4/ip_sockglue.c b/net/ipv4/ip_sockglue.c index cce9cb25f3b3..1a6952921e07 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -1369,12 +1369,13 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname, * ipv4_pktinfo_prepare - transfer some info from rtable to skb * @sk: socket * @skb: buffer + * @drop_dst: if true, drops skb dst * * To support IP_CMSG_PKTINFO option, we store rt_iif and specific * destination in skb->cb[] before dst drop. * This way, receiver doesn't make cache line misses to read rtable. */ -void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb) +void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb, bool drop_dst) { struct in_pktinfo *pktinfo = PKTINFO_SKB_CB(skb); bool prepare = inet_test_bit(PKTINFO, sk) || @@ -1403,7 +1404,8 @@ void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb) pktinfo->ipi_ifindex = 0; pktinfo->ipi_spec_dst.s_addr = 0; } - skb_dst_drop(skb); + if (drop_dst) + skb_dst_drop(skb); }
int ip_setsockopt(struct sock *sk, int level, int optname, sockptr_t optval, diff --git a/net/ipv4/ipmr.c b/net/ipv4/ipmr.c index 0063a237253b..e49242706b5f 100644 --- a/net/ipv4/ipmr.c +++ b/net/ipv4/ipmr.c @@ -1073,7 +1073,7 @@ static int ipmr_cache_report(const struct mr_table *mrt, msg = (struct igmpmsg *)skb_network_header(skb); msg->im_vif = vifi; msg->im_vif_hi = vifi >> 8; - ipv4_pktinfo_prepare(mroute_sk, pkt); + ipv4_pktinfo_prepare(mroute_sk, pkt, false); memcpy(skb->cb, pkt->cb, sizeof(skb->cb)); /* Add our header */ igmp = skb_put(skb, sizeof(struct igmphdr)); diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c index 4b5db5d1edc2..c0ef81f0bcee 100644 --- a/net/ipv4/raw.c +++ b/net/ipv4/raw.c @@ -292,7 +292,7 @@ static int raw_rcv_skb(struct sock *sk, struct sk_buff *skb)
/* Charge it to the socket. */
- ipv4_pktinfo_prepare(sk, skb); + ipv4_pktinfo_prepare(sk, skb, true); if (sock_queue_rcv_skb_reason(sk, skb, &reason) < 0) { kfree_skb_reason(skb, reason); return NET_RX_DROP; diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index 7be4ddc80d95..8e5a8b3b22c6 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2167,7 +2167,7 @@ static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
udp_csum_pull_header(skb);
- ipv4_pktinfo_prepare(sk, skb); + ipv4_pktinfo_prepare(sk, skb, true); return __udp_queue_rcv_skb(sk, skb);
csum_error: