From 7905a2479bdb02a92c98ec10d2ae4f88675d73b9 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Sun, 24 Jul 2022 17:54:37 +0200 Subject: [PATCH] 5.18-stable patches added patches: bpf-make-sure-mac_header-was-set-before-using-it.patch --- ...e-mac_header-was-set-before-using-it.patch | 74 +++++++++++++++++++ queue-5.18/series | 1 + 2 files changed, 75 insertions(+) create mode 100644 queue-5.18/bpf-make-sure-mac_header-was-set-before-using-it.patch diff --git a/queue-5.18/bpf-make-sure-mac_header-was-set-before-using-it.patch b/queue-5.18/bpf-make-sure-mac_header-was-set-before-using-it.patch new file mode 100644 index 00000000000..1437480f098 --- /dev/null +++ b/queue-5.18/bpf-make-sure-mac_header-was-set-before-using-it.patch @@ -0,0 +1,74 @@ +From 0326195f523a549e0a9d7fd44c70b26fd7265090 Mon Sep 17 00:00:00 2001 +From: Eric Dumazet +Date: Thu, 7 Jul 2022 12:39:00 +0000 +Subject: bpf: Make sure mac_header was set before using it + +From: Eric Dumazet + +commit 0326195f523a549e0a9d7fd44c70b26fd7265090 upstream. + +Classic BPF has a way to load bytes starting from the mac header. + +Some skbs do not have a mac header, and skb_mac_header() +in this case is returning a pointer that 65535 bytes after +skb->head. + +Existing range check in bpf_internal_load_pointer_neg_helper() +was properly kicking and no illegal access was happening. + +New sanity check in skb_mac_header() is firing, so we need +to avoid it. + +WARNING: CPU: 1 PID: 28990 at include/linux/skbuff.h:2785 skb_mac_header include/linux/skbuff.h:2785 [inline] +WARNING: CPU: 1 PID: 28990 at include/linux/skbuff.h:2785 bpf_internal_load_pointer_neg_helper+0x1b1/0x1c0 kernel/bpf/core.c:74 +Modules linked in: +CPU: 1 PID: 28990 Comm: syz-executor.0 Not tainted 5.19.0-rc4-syzkaller-00865-g4874fb9484be #0 +Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022 +RIP: 0010:skb_mac_header include/linux/skbuff.h:2785 [inline] +RIP: 0010:bpf_internal_load_pointer_neg_helper+0x1b1/0x1c0 kernel/bpf/core.c:74 +Code: ff ff 45 31 f6 e9 5a ff ff ff e8 aa 27 40 00 e9 3b ff ff ff e8 90 27 40 00 e9 df fe ff ff e8 86 27 40 00 eb 9e e8 2f 2c f3 ff <0f> 0b eb b1 e8 96 27 40 00 e9 79 fe ff ff 90 41 57 41 56 41 55 41 +RSP: 0018:ffffc9000309f668 EFLAGS: 00010216 +RAX: 0000000000000118 RBX: ffffffffffeff00c RCX: ffffc9000e417000 +RDX: 0000000000040000 RSI: ffffffff81873f21 RDI: 0000000000000003 +RBP: ffff8880842878c0 R08: 0000000000000003 R09: 000000000000ffff +R10: 000000000000ffff R11: 0000000000000001 R12: 0000000000000004 +R13: ffff88803ac56c00 R14: 000000000000ffff R15: dffffc0000000000 +FS: 00007f5c88a16700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 +CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 +CR2: 00007fdaa9f6c058 CR3: 000000003a82c000 CR4: 00000000003506e0 +DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 +DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 +Call Trace: + +____bpf_skb_load_helper_32 net/core/filter.c:276 [inline] +bpf_skb_load_helper_32+0x191/0x220 net/core/filter.c:264 + +Fixes: f9aefd6b2aa3 ("net: warn if mac header was not set") +Reported-by: syzbot +Signed-off-by: Eric Dumazet +Signed-off-by: Daniel Borkmann +Link: https://lore.kernel.org/bpf/20220707123900.945305-1-edumazet@google.com +Signed-off-by: Greg Kroah-Hartman +--- + kernel/bpf/core.c | 8 +++++--- + 1 file changed, 5 insertions(+), 3 deletions(-) + +--- a/kernel/bpf/core.c ++++ b/kernel/bpf/core.c +@@ -68,11 +68,13 @@ void *bpf_internal_load_pointer_neg_help + { + u8 *ptr = NULL; + +- if (k >= SKF_NET_OFF) ++ if (k >= SKF_NET_OFF) { + ptr = skb_network_header(skb) + k - SKF_NET_OFF; +- else if (k >= SKF_LL_OFF) ++ } else if (k >= SKF_LL_OFF) { ++ if (unlikely(!skb_mac_header_was_set(skb))) ++ return NULL; + ptr = skb_mac_header(skb) + k - SKF_LL_OFF; +- ++ } + if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb)) + return ptr; + diff --git a/queue-5.18/series b/queue-5.18/series index 6bcc6581cbc..3bfa5c1aefa 100644 --- a/queue-5.18/series +++ b/queue-5.18/series @@ -131,3 +131,4 @@ kvm-selftests-fix-target-thread-to-be-migrated-in-rseq_test.patch spi-bcm2835-bcm2835_spi_handle_err-fix-null-pointer-deref-for-non-dma-transfers.patch kvm-don-t-null-dereference-ops-destroy.patch mm-mempolicy-fix-uninit-value-in-mpol_rebind_policy.patch +bpf-make-sure-mac_header-was-set-before-using-it.patch -- 2.47.3