* [PATCH 4.19 0/1] Fix CVE-2023-52435 @ 2024-08-30 8:44 hsimeliere.opensource 2024-08-30 8:44 ` [PATCH 4.19 1/1] net: prevent mss overflow in skb_segment() hsimeliere.opensource 0 siblings, 1 reply; 3+ messages in thread From: hsimeliere.opensource @ 2024-08-30 8:44 UTC (permalink / raw) To: stable https://nvd.nist.gov/vuln/detail/CVE-2023-52435 ^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH 4.19 1/1] net: prevent mss overflow in skb_segment() 2024-08-30 8:44 [PATCH 4.19 0/1] Fix CVE-2023-52435 hsimeliere.opensource @ 2024-08-30 8:44 ` hsimeliere.opensource 2024-08-30 13:07 ` Greg Kroah-Hartman 0 siblings, 1 reply; 3+ messages in thread From: hsimeliere.opensource @ 2024-08-30 8:44 UTC (permalink / raw) To: stable Cc: Eric Dumazet, Marcelo Ricardo Leitner, Willem de Bruijn, Jakub Kicinski, Greg Kroah-Hartman, Hugo SIMELIERE From: Eric Dumazet <edumazet@google.com> commit 23d05d563b7e7b0314e65c8e882bc27eac2da8e7 upstream. Once again syzbot is able to crash the kernel in skb_segment() [1] GSO_BY_FRAGS is a forbidden value, but unfortunately the following computation in skb_segment() can reach it quite easily : mss = mss * partial_segs; 65535 = 3 * 5 * 17 * 257, so many initial values of mss can lead to a bad final result. Make sure to limit segmentation so that the new mss value is smaller than GSO_BY_FRAGS. [1] general protection fault, probably for non-canonical address 0xdffffc000000000e: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000070-0x0000000000000077] CPU: 1 PID: 5079 Comm: syz-executor993 Not tainted 6.7.0-rc4-syzkaller-00141-g1ae4cd3cbdd0 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 RIP: 0010:skb_segment+0x181d/0x3f30 net/core/skbuff.c:4551 Code: 83 e3 02 e9 fb ed ff ff e8 90 68 1c f9 48 8b 84 24 f8 00 00 00 48 8d 78 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 8a 21 00 00 48 8b 84 24 f8 00 RSP: 0018:ffffc900043473d0 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000010046 RCX: ffffffff886b1597 RDX: 000000000000000e RSI: ffffffff886b2520 RDI: 0000000000000070 RBP: ffffc90004347578 R08: 0000000000000005 R09: 000000000000ffff R10: 000000000000ffff R11: 0000000000000002 R12: ffff888063202ac0 R13: 0000000000010000 R14: 000000000000ffff R15: 0000000000000046 FS: 0000555556e7e380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020010000 CR3: 0000000027ee2000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> udp6_ufo_fragment+0xa0e/0xd00 net/ipv6/udp_offload.c:109 ipv6_gso_segment+0x534/0x17e0 net/ipv6/ip6_offload.c:120 skb_mac_gso_segment+0x290/0x610 net/core/gso.c:53 __skb_gso_segment+0x339/0x710 net/core/gso.c:124 skb_gso_segment include/net/gso.h:83 [inline] validate_xmit_skb+0x36c/0xeb0 net/core/dev.c:3626 __dev_queue_xmit+0x6f3/0x3d60 net/core/dev.c:4338 dev_queue_xmit include/linux/netdevice.h:3134 [inline] packet_xmit+0x257/0x380 net/packet/af_packet.c:276 packet_snd net/packet/af_packet.c:3087 [inline] packet_sendmsg+0x24c6/0x5220 net/packet/af_packet.c:3119 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0xd5/0x180 net/socket.c:745 __sys_sendto+0x255/0x340 net/socket.c:2190 __do_sys_sendto net/socket.c:2202 [inline] __se_sys_sendto net/socket.c:2198 [inline] __x64_sys_sendto+0xe0/0x1b0 net/socket.c:2198 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b RIP: 0033:0x7f8692032aa9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fff8d685418 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f8692032aa9 RDX: 0000000000010048 RSI: 00000000200000c0 RDI: 0000000000000003 RBP: 00000000000f4240 R08: 0000000020000540 R09: 0000000000000014 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff8d685480 R13: 0000000000000001 R14: 00007fff8d685480 R15: 0000000000000003 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:skb_segment+0x181d/0x3f30 net/core/skbuff.c:4551 Code: 83 e3 02 e9 fb ed ff ff e8 90 68 1c f9 48 8b 84 24 f8 00 00 00 48 8d 78 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 8a 21 00 00 48 8b 84 24 f8 00 RSP: 0018:ffffc900043473d0 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000010046 RCX: ffffffff886b1597 RDX: 000000000000000e RSI: ffffffff886b2520 RDI: 0000000000000070 RBP: ffffc90004347578 R08: 0000000000000005 R09: 000000000000ffff R10: 000000000000ffff R11: 0000000000000002 R12: ffff888063202ac0 R13: 0000000000010000 R14: 000000000000ffff R15: 0000000000000046 FS: 0000555556e7e380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020010000 CR3: 0000000027ee2000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Fixes: 3953c46c3ac7 ("sk_buff: allow segmenting based on frag sizes") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://lore.kernel.org/r/20231212164621.4131800-1-edumazet@google.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Hugo SIMELIERE <hsimeliere.opensource@witekio.com> --- net/core/skbuff.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index e03cd719b86b..cb336e79e05f 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3625,8 +3625,9 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb, /* GSO partial only requires that we trim off any excess that * doesn't fit into an MSS sized block, so take care of that * now. + * Cap len to not accidentally hit GSO_BY_FRAGS. */ - partial_segs = len / mss; + partial_segs = min(len, GSO_BY_FRAGS - 1U) / mss; if (partial_segs > 1) mss *= partial_segs; else -- 2.43.0 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH 4.19 1/1] net: prevent mss overflow in skb_segment() 2024-08-30 8:44 ` [PATCH 4.19 1/1] net: prevent mss overflow in skb_segment() hsimeliere.opensource @ 2024-08-30 13:07 ` Greg Kroah-Hartman 0 siblings, 0 replies; 3+ messages in thread From: Greg Kroah-Hartman @ 2024-08-30 13:07 UTC (permalink / raw) To: hsimeliere.opensource Cc: stable, Eric Dumazet, Marcelo Ricardo Leitner, Willem de Bruijn, Jakub Kicinski On Fri, Aug 30, 2024 at 10:44:54AM +0200, hsimeliere.opensource@witekio.com wrote: > From: Eric Dumazet <edumazet@google.com> > > commit 23d05d563b7e7b0314e65c8e882bc27eac2da8e7 upstream. > > Once again syzbot is able to crash the kernel in skb_segment() [1] > > GSO_BY_FRAGS is a forbidden value, but unfortunately the following > computation in skb_segment() can reach it quite easily : > > mss = mss * partial_segs; > > 65535 = 3 * 5 * 17 * 257, so many initial values of mss can lead to > a bad final result. > > Make sure to limit segmentation so that the new mss value is smaller > than GSO_BY_FRAGS. > > [1] > > general protection fault, probably for non-canonical address 0xdffffc000000000e: 0000 [#1] PREEMPT SMP KASAN > KASAN: null-ptr-deref in range [0x0000000000000070-0x0000000000000077] > CPU: 1 PID: 5079 Comm: syz-executor993 Not tainted 6.7.0-rc4-syzkaller-00141-g1ae4cd3cbdd0 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023 > RIP: 0010:skb_segment+0x181d/0x3f30 net/core/skbuff.c:4551 > Code: 83 e3 02 e9 fb ed ff ff e8 90 68 1c f9 48 8b 84 24 f8 00 00 00 48 8d 78 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 8a 21 00 00 48 8b 84 24 f8 00 > RSP: 0018:ffffc900043473d0 EFLAGS: 00010202 > RAX: dffffc0000000000 RBX: 0000000000010046 RCX: ffffffff886b1597 > RDX: 000000000000000e RSI: ffffffff886b2520 RDI: 0000000000000070 > RBP: ffffc90004347578 R08: 0000000000000005 R09: 000000000000ffff > R10: 000000000000ffff R11: 0000000000000002 R12: ffff888063202ac0 > R13: 0000000000010000 R14: 000000000000ffff R15: 0000000000000046 > FS: 0000555556e7e380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000020010000 CR3: 0000000027ee2000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > <TASK> > udp6_ufo_fragment+0xa0e/0xd00 net/ipv6/udp_offload.c:109 > ipv6_gso_segment+0x534/0x17e0 net/ipv6/ip6_offload.c:120 > skb_mac_gso_segment+0x290/0x610 net/core/gso.c:53 > __skb_gso_segment+0x339/0x710 net/core/gso.c:124 > skb_gso_segment include/net/gso.h:83 [inline] > validate_xmit_skb+0x36c/0xeb0 net/core/dev.c:3626 > __dev_queue_xmit+0x6f3/0x3d60 net/core/dev.c:4338 > dev_queue_xmit include/linux/netdevice.h:3134 [inline] > packet_xmit+0x257/0x380 net/packet/af_packet.c:276 > packet_snd net/packet/af_packet.c:3087 [inline] > packet_sendmsg+0x24c6/0x5220 net/packet/af_packet.c:3119 > sock_sendmsg_nosec net/socket.c:730 [inline] > __sock_sendmsg+0xd5/0x180 net/socket.c:745 > __sys_sendto+0x255/0x340 net/socket.c:2190 > __do_sys_sendto net/socket.c:2202 [inline] > __se_sys_sendto net/socket.c:2198 [inline] > __x64_sys_sendto+0xe0/0x1b0 net/socket.c:2198 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x63/0x6b > RIP: 0033:0x7f8692032aa9 > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007fff8d685418 EFLAGS: 00000246 ORIG_RAX: 000000000000002c > RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f8692032aa9 > RDX: 0000000000010048 RSI: 00000000200000c0 RDI: 0000000000000003 > RBP: 00000000000f4240 R08: 0000000020000540 R09: 0000000000000014 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff8d685480 > R13: 0000000000000001 R14: 00007fff8d685480 R15: 0000000000000003 > </TASK> > Modules linked in: > ---[ end trace 0000000000000000 ]--- > RIP: 0010:skb_segment+0x181d/0x3f30 net/core/skbuff.c:4551 > Code: 83 e3 02 e9 fb ed ff ff e8 90 68 1c f9 48 8b 84 24 f8 00 00 00 48 8d 78 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e 8a 21 00 00 48 8b 84 24 f8 00 > RSP: 0018:ffffc900043473d0 EFLAGS: 00010202 > RAX: dffffc0000000000 RBX: 0000000000010046 RCX: ffffffff886b1597 > RDX: 000000000000000e RSI: ffffffff886b2520 RDI: 0000000000000070 > RBP: ffffc90004347578 R08: 0000000000000005 R09: 000000000000ffff > R10: 000000000000ffff R11: 0000000000000002 R12: ffff888063202ac0 > R13: 0000000000010000 R14: 000000000000ffff R15: 0000000000000046 > FS: 0000555556e7e380(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000020010000 CR3: 0000000027ee2000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Fixes: 3953c46c3ac7 ("sk_buff: allow segmenting based on frag sizes") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> > Reviewed-by: Willem de Bruijn <willemb@google.com> > Link: https://lore.kernel.org/r/20231212164621.4131800-1-edumazet@google.com > Signed-off-by: Jakub Kicinski <kuba@kernel.org> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Signed-off-by: Hugo SIMELIERE <hsimeliere.opensource@witekio.com> > --- > net/core/skbuff.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/net/core/skbuff.c b/net/core/skbuff.c > index e03cd719b86b..cb336e79e05f 100644 > --- a/net/core/skbuff.c > +++ b/net/core/skbuff.c > @@ -3625,8 +3625,9 @@ struct sk_buff *skb_segment(struct sk_buff *head_skb, > /* GSO partial only requires that we trim off any excess that > * doesn't fit into an MSS sized block, so take care of that > * now. > + * Cap len to not accidentally hit GSO_BY_FRAGS. > */ > - partial_segs = len / mss; > + partial_segs = min(len, GSO_BY_FRAGS - 1U) / mss; > if (partial_segs > 1) > mss *= partial_segs; > else > -- Note, this backport causes a build warning. I'll go fix it up by hand, but next time please be more careful. thanks, greg k-h ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2024-08-30 13:07 UTC | newest] Thread overview: 3+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2024-08-30 8:44 [PATCH 4.19 0/1] Fix CVE-2023-52435 hsimeliere.opensource 2024-08-30 8:44 ` [PATCH 4.19 1/1] net: prevent mss overflow in skb_segment() hsimeliere.opensource 2024-08-30 13:07 ` Greg Kroah-Hartman
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