| Message ID | 20240124121538.3188769-1-nicolas.dichtel@6wind.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] ipmr: fix kernel panic when forwarding mcast packets | expand |
On Wed, Jan 24, 2024 at 1:15 PM Nicolas Dichtel <nicolas.dichtel@6wind.com> wrote: > > The stacktrace was: > [ 86.305548] BUG: kernel NULL pointer dereference, address: 0000000000000092 > ... > 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> > --- > include/net/ip.h | 2 +- > net/ipv4/ip_sockglue.c | 5 +++-- > net/ipv4/ipmr.c | 2 +- > net/ipv4/raw.c | 2 +- > net/ipv4/udp.c | 2 +- > 5 files changed, 7 insertions(+), 6 deletions(-) > > diff --git a/include/net/ip.h b/include/net/ip.h > index de0c69c57e3c..1e7f2e417ed2 100644 > --- a/include/net/ip.h > +++ b/include/net/ip.h > @@ -767,7 +767,7 @@ 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 keep_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 7aa9dc0e6760..fe1ab335324f 100644 > --- a/net/ipv4/ip_sockglue.c > +++ b/net/ipv4/ip_sockglue.c > @@ -1368,7 +1368,7 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname, > * 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 keep_dst) > { > struct in_pktinfo *pktinfo = PKTINFO_SKB_CB(skb); > bool prepare = inet_test_bit(PKTINFO, sk) || > @@ -1397,7 +1397,8 @@ 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 (keep_dst == false) > + skb_dst_drop(skb); IMO this would look nicer if you had void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb, bool drop_dst) .. if (drop_dst) skb_dst_drop(skb); Reviewed-by: Eric Dumazet <edumazet@google.com> Thanks.
Le 24/01/2024 à 15:21, Eric Dumazet a écrit : > On Wed, Jan 24, 2024 at 1:15 PM Nicolas Dichtel > <nicolas.dichtel@6wind.com> wrote: >> >> The stacktrace was: >> [ 86.305548] BUG: kernel NULL pointer dereference, address: 0000000000000092 >> > ... > >> 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> >> --- >> include/net/ip.h | 2 +- >> net/ipv4/ip_sockglue.c | 5 +++-- >> net/ipv4/ipmr.c | 2 +- >> net/ipv4/raw.c | 2 +- >> net/ipv4/udp.c | 2 +- >> 5 files changed, 7 insertions(+), 6 deletions(-) >> >> diff --git a/include/net/ip.h b/include/net/ip.h >> index de0c69c57e3c..1e7f2e417ed2 100644 >> --- a/include/net/ip.h >> +++ b/include/net/ip.h >> @@ -767,7 +767,7 @@ 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 keep_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 7aa9dc0e6760..fe1ab335324f 100644 >> --- a/net/ipv4/ip_sockglue.c >> +++ b/net/ipv4/ip_sockglue.c >> @@ -1368,7 +1368,7 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname, >> * 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 keep_dst) >> { >> struct in_pktinfo *pktinfo = PKTINFO_SKB_CB(skb); >> bool prepare = inet_test_bit(PKTINFO, sk) || >> @@ -1397,7 +1397,8 @@ 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 (keep_dst == false) >> + skb_dst_drop(skb); > > IMO this would look nicer if you had > > void ipv4_pktinfo_prepare(const struct sock *sk, struct sk_buff *skb, > bool drop_dst) > .. > if (drop_dst) > skb_dst_drop(skb); Agreed, I hesitated :) > > Reviewed-by: Eric Dumazet <edumazet@google.com> > > Thanks. Thank you, Nicolas
On Wed, 24 Jan 2024 13:15:38 +0100 Nicolas Dichtel wrote: > --- a/net/ipv4/ip_sockglue.c > +++ b/net/ipv4/ip_sockglue.c > @@ -1368,7 +1368,7 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname, > * 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 keep_dst) kdoc missing here: net/ipv4/ip_sockglue.c:1373: warning: Function parameter or struct member 'keep_dst' not described in 'ipv4_pktinfo_prepare'
I missed this path, thanks for fixing it. Eric's suggestion looks good to me.
diff --git a/include/net/ip.h b/include/net/ip.h index de0c69c57e3c..1e7f2e417ed2 100644 --- a/include/net/ip.h +++ b/include/net/ip.h @@ -767,7 +767,7 @@ 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 keep_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 7aa9dc0e6760..fe1ab335324f 100644 --- a/net/ipv4/ip_sockglue.c +++ b/net/ipv4/ip_sockglue.c @@ -1368,7 +1368,7 @@ int do_ip_setsockopt(struct sock *sk, int level, int optname, * 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 keep_dst) { struct in_pktinfo *pktinfo = PKTINFO_SKB_CB(skb); bool prepare = inet_test_bit(PKTINFO, sk) || @@ -1397,7 +1397,8 @@ 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 (keep_dst == false) + 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 9d6f59531b3a..84bddaffb9eb 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, true); 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 27da9d7294c0..99e929c7505b 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, false); 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 148ffb007969..32b244ad9d51 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -2169,7 +2169,7 @@ 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, false); return __udp_queue_rcv_skb(sk, skb); csum_error:
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> --- include/net/ip.h | 2 +- net/ipv4/ip_sockglue.c | 5 +++-- net/ipv4/ipmr.c | 2 +- net/ipv4/raw.c | 2 +- net/ipv4/udp.c | 2 +- 5 files changed, 7 insertions(+), 6 deletions(-)