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[PATCH openEuler-22.03-LTS-SP1] netfilter: nf_tables: disallow anonymous set with timeout flag
by Guo Mengqi 14 May '24

14 May '24

From: Pablo Neira Ayuso <pablo(a)netfilter.org> mainline inclusion from mainline-v6.8 commit 16603605b667b70da974bea8216c93e7db043bf1 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9AK56 CVE: CVE-2024-26642 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- Anonymous sets are never used with timeout from userspace, reject this. Exception to this rule is NFT_SET_EVAL to ensure legacy meters still work. Cc: stable(a)vger.kernel.org Fixes: 761da2935d6e ("netfilter: nf_tables: add set timeout API support") Reported-by: lonial con <kongln9170(a)gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo(a)netfilter.org> Signed-off-by: Ziyang Xuan <william.xuanziyang(a)huawei.com> --- net/netfilter/nf_tables_api.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 231e710ec55e..6d64694168ec 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4358,6 +4358,9 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk, if ((flags & (NFT_SET_EVAL | NFT_SET_OBJECT)) == (NFT_SET_EVAL | NFT_SET_OBJECT)) return -EOPNOTSUPP; + if ((flags & (NFT_SET_ANONYMOUS | NFT_SET_TIMEOUT | NFT_SET_EVAL)) == + (NFT_SET_ANONYMOUS | NFT_SET_TIMEOUT)) + return -EOPNOTSUPP; } dtype = 0; -- 2.17.1

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[PATCH openEuler-22.03-LTS] netfilter: nf_tables: disallow anonymous set with timeout flag
by Guo Mengqi 14 May '24

14 May '24

From: Pablo Neira Ayuso <pablo(a)netfilter.org> mainline inclusion from mainline-v6.8 commit 16603605b667b70da974bea8216c93e7db043bf1 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9AK56 CVE: CVE-2024-26642 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- Anonymous sets are never used with timeout from userspace, reject this. Exception to this rule is NFT_SET_EVAL to ensure legacy meters still work. Cc: stable(a)vger.kernel.org Fixes: 761da2935d6e ("netfilter: nf_tables: add set timeout API support") Reported-by: lonial con <kongln9170(a)gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo(a)netfilter.org> Signed-off-by: Ziyang Xuan <william.xuanziyang(a)huawei.com> --- net/netfilter/nf_tables_api.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 0f117e44bf05..78f2c5fc8efc 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4356,6 +4356,9 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk, if ((flags & (NFT_SET_EVAL | NFT_SET_OBJECT)) == (NFT_SET_EVAL | NFT_SET_OBJECT)) return -EOPNOTSUPP; + if ((flags & (NFT_SET_ANONYMOUS | NFT_SET_TIMEOUT | NFT_SET_EVAL)) == + (NFT_SET_ANONYMOUS | NFT_SET_TIMEOUT)) + return -EOPNOTSUPP; } dtype = 0; -- 2.17.1

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[PATCH openEuler-22.03-LTS-SP2] netfilter: nf_tables: disallow timeout for anonymous sets
by Guo Mengqi 14 May '24

14 May '24

From: Pablo Neira Ayuso <pablo(a)netfilter.org> mainline inclusion from mainline-v6.4-rc2 commit e26d3009efda338f19016df4175f354a9bd0a4ab category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9AK6C CVE: CVE-2023-52620 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- Never used from userspace, disallow these parameters. Signed-off-by: Pablo Neira Ayuso <pablo(a)netfilter.org> Conflicts: net/netfilter/nf_tables_api.c Signed-off-by: Zhengchao Shao <shaozhengchao(a)huawei.com> --- net/netfilter/nf_tables_api.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 566053c7dc2e..c17c1990234f 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4399,6 +4399,9 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk, if (!(flags & NFT_SET_TIMEOUT)) return -EINVAL; + if (flags & NFT_SET_ANONYMOUS) + return -EOPNOTSUPP; + err = nf_msecs_to_jiffies64(nla[NFTA_SET_TIMEOUT], &timeout); if (err) return err; @@ -4407,6 +4410,10 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk, if (nla[NFTA_SET_GC_INTERVAL] != NULL) { if (!(flags & NFT_SET_TIMEOUT)) return -EINVAL; + + if (flags & NFT_SET_ANONYMOUS) + return -EOPNOTSUPP; + gc_int = ntohl(nla_get_be32(nla[NFTA_SET_GC_INTERVAL])); } -- 2.17.1

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[PATCH openEuler-22.03-LTS] netfilter: nf_tables: disallow timeout for anonymous sets
by Guo Mengqi 14 May '24

14 May '24

From: Pablo Neira Ayuso <pablo(a)netfilter.org> mainline inclusion from mainline-v6.4-rc2 commit e26d3009efda338f19016df4175f354a9bd0a4ab category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9AK6C CVE: CVE-2023-52620 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- Never used from userspace, disallow these parameters. Signed-off-by: Pablo Neira Ayuso <pablo(a)netfilter.org> Conflicts: net/netfilter/nf_tables_api.c Signed-off-by: Zhengchao Shao <shaozhengchao(a)huawei.com> --- net/netfilter/nf_tables_api.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index c547d7beb6d1..0f117e44bf05 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4397,6 +4397,9 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk, if (!(flags & NFT_SET_TIMEOUT)) return -EINVAL; + if (flags & NFT_SET_ANONYMOUS) + return -EOPNOTSUPP; + err = nf_msecs_to_jiffies64(nla[NFTA_SET_TIMEOUT], &timeout); if (err) return err; @@ -4405,6 +4408,10 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk, if (nla[NFTA_SET_GC_INTERVAL] != NULL) { if (!(flags & NFT_SET_TIMEOUT)) return -EINVAL; + + if (flags & NFT_SET_ANONYMOUS) + return -EOPNOTSUPP; + gc_int = ntohl(nla_get_be32(nla[NFTA_SET_GC_INTERVAL])); } -- 2.17.1

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[PATCH openEuler-22.03-LTS-SP1] netfilter: nf_tables: disallow timeout for anonymous sets
by Guo Mengqi 14 May '24

14 May '24

From: Pablo Neira Ayuso <pablo(a)netfilter.org> mainline inclusion from mainline-v6.4-rc2 commit e26d3009efda338f19016df4175f354a9bd0a4ab category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9AK6C CVE: CVE-2023-52620 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- Never used from userspace, disallow these parameters. Signed-off-by: Pablo Neira Ayuso <pablo(a)netfilter.org> Conflicts: net/netfilter/nf_tables_api.c Signed-off-by: Zhengchao Shao <shaozhengchao(a)huawei.com> --- net/netfilter/nf_tables_api.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 07355fd7b2a2..231e710ec55e 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4399,6 +4399,9 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk, if (!(flags & NFT_SET_TIMEOUT)) return -EINVAL; + if (flags & NFT_SET_ANONYMOUS) + return -EOPNOTSUPP; + err = nf_msecs_to_jiffies64(nla[NFTA_SET_TIMEOUT], &timeout); if (err) return err; @@ -4407,6 +4410,10 @@ static int nf_tables_newset(struct net *net, struct sock *nlsk, if (nla[NFTA_SET_GC_INTERVAL] != NULL) { if (!(flags & NFT_SET_TIMEOUT)) return -EINVAL; + + if (flags & NFT_SET_ANONYMOUS) + return -EOPNOTSUPP; + gc_int = ntohl(nla_get_be32(nla[NFTA_SET_GC_INTERVAL])); } -- 2.17.1

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[PATCH openEuler-22.03-LTS-SP1] netfilter: nf_tables: mark set as dead when unbinding anonymous set with timeout
by Guo Mengqi 14 May '24

14 May '24

From: Pablo Neira Ayuso <pablo(a)netfilter.org> mainline inclusion from mainline-v6.8 commit 552705a3650bbf46a22b1adedc1b04181490fc36 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9AK7L CVE: CVE-2024-26643 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… --------------------------- While the rhashtable set gc runs asynchronously, a race allows it to collect elements from anonymous sets with timeouts while it is being released from the commit path. Mingi Cho originally reported this issue in a different path in 6.1.x with a pipapo set with low timeouts which is not possible upstream since 7395dfacfff6 ("netfilter: nf_tables: use timestamp to check for set element timeout"). Fix this by setting on the dead flag for anonymous sets to skip async gc in this case. According to 08e4c8c5919f ("netfilter: nf_tables: mark newset as dead on transaction abort"), Florian plans to accelerate abort path by releasing objects via workqueue, therefore, this sets on the dead flag for abort path too. Cc: stable(a)vger.kernel.org Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane") Reported-by: Mingi Cho <mgcho.minic(a)gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo(a)netfilter.org> Signed-off-by: Liu Jian <liujian56(a)huawei.com> --- net/netfilter/nf_tables_api.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 0a7f7ed33406..07355fd7b2a2 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4674,6 +4674,7 @@ static void nf_tables_unbind_set(const struct nft_ctx *ctx, struct nft_set *set, if (list_empty(&set->bindings) && nft_set_is_anonymous(set)) { list_del_rcu(&set->list); + set->dead = 1; if (event) nf_tables_set_notify(ctx, set, NFT_MSG_DELSET, GFP_KERNEL); -- 2.17.1

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[PATCH openEuler-22.03-LTS-SP2] netfilter: nf_tables: mark set as dead when unbinding anonymous set with timeout
by Guo Mengqi 14 May '24

14 May '24

From: Pablo Neira Ayuso <pablo(a)netfilter.org> mainline inclusion from mainline-v6.8 commit 552705a3650bbf46a22b1adedc1b04181490fc36 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9AK7L CVE: CVE-2024-26643 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… --------------------------- While the rhashtable set gc runs asynchronously, a race allows it to collect elements from anonymous sets with timeouts while it is being released from the commit path. Mingi Cho originally reported this issue in a different path in 6.1.x with a pipapo set with low timeouts which is not possible upstream since 7395dfacfff6 ("netfilter: nf_tables: use timestamp to check for set element timeout"). Fix this by setting on the dead flag for anonymous sets to skip async gc in this case. According to 08e4c8c5919f ("netfilter: nf_tables: mark newset as dead on transaction abort"), Florian plans to accelerate abort path by releasing objects via workqueue, therefore, this sets on the dead flag for abort path too. Cc: stable(a)vger.kernel.org Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane") Reported-by: Mingi Cho <mgcho.minic(a)gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo(a)netfilter.org> Signed-off-by: Liu Jian <liujian56(a)huawei.com> --- net/netfilter/nf_tables_api.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 3667b4daf1bb..566053c7dc2e 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4674,6 +4674,7 @@ static void nf_tables_unbind_set(const struct nft_ctx *ctx, struct nft_set *set, if (list_empty(&set->bindings) && nft_set_is_anonymous(set)) { list_del_rcu(&set->list); + set->dead = 1; if (event) nf_tables_set_notify(ctx, set, NFT_MSG_DELSET, GFP_KERNEL); -- 2.17.1

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[PATCH openEuler-22.03-LTS] tracing: Ensure visibility when inserting an element into tracing_map
by Guo Mengqi 14 May '24

14 May '24

From: Petr Pavlu <petr.pavlu(a)suse.com> mainline inclusion from mainline-v6.8-rc2 commit 2b44760609e9eaafc9d234a6883d042fc21132a7 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9BV24 CVE: CVE-2024-26645 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- Running the following two commands in parallel on a multi-processor AArch64 machine can sporadically produce an unexpected warning about duplicate histogram entries: $ while true; do echo hist:key=id.syscall:val=hitcount > \ /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist sleep 0.001 done $ stress-ng --sysbadaddr $(nproc) The warning looks as follows: [ 2911.172474] ------------[ cut here ]------------ [ 2911.173111] Duplicates detected: 1 [ 2911.173574] WARNING: CPU: 2 PID: 12247 at kernel/trace/tracing_map.c:983 tracing_map_sort_entries+0x3e0/0x408 [ 2911.174702] Modules linked in: iscsi_ibft(E) iscsi_boot_sysfs(E) rfkill(E) af_packet(E) nls_iso8859_1(E) nls_cp437(E) vfat(E) fat(E) ena(E) tiny_power_button(E) qemu_fw_cfg(E) button(E) fuse(E) efi_pstore(E) ip_tables(E) x_tables(E) xfs(E) libcrc32c(E) aes_ce_blk(E) aes_ce_cipher(E) crct10dif_ce(E) polyval_ce(E) polyval_generic(E) ghash_ce(E) gf128mul(E) sm4_ce_gcm(E) sm4_ce_ccm(E) sm4_ce(E) sm4_ce_cipher(E) sm4(E) sm3_ce(E) sm3(E) sha3_ce(E) sha512_ce(E) sha512_arm64(E) sha2_ce(E) sha256_arm64(E) nvme(E) sha1_ce(E) nvme_core(E) nvme_auth(E) t10_pi(E) sg(E) scsi_mod(E) scsi_common(E) efivarfs(E) [ 2911.174738] Unloaded tainted modules: cppc_cpufreq(E):1 [ 2911.180985] CPU: 2 PID: 12247 Comm: cat Kdump: loaded Tainted: G E 6.7.0-default #2 1b58bbb22c97e4399dc09f92d309344f69c44a01 [ 2911.182398] Hardware name: Amazon EC2 c7g.8xlarge/, BIOS 1.0 11/1/2018 [ 2911.183208] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) [ 2911.184038] pc : tracing_map_sort_entries+0x3e0/0x408 [ 2911.184667] lr : tracing_map_sort_entries+0x3e0/0x408 [ 2911.185310] sp : ffff8000a1513900 [ 2911.185750] x29: ffff8000a1513900 x28: ffff0003f272fe80 x27: 0000000000000001 [ 2911.186600] x26: ffff0003f272fe80 x25: 0000000000000030 x24: 0000000000000008 [ 2911.187458] x23: ffff0003c5788000 x22: ffff0003c16710c8 x21: ffff80008017f180 [ 2911.188310] x20: ffff80008017f000 x19: ffff80008017f180 x18: ffffffffffffffff [ 2911.189160] x17: 0000000000000000 x16: 0000000000000000 x15: ffff8000a15134b8 [ 2911.190015] x14: 0000000000000000 x13: 205d373432323154 x12: 5b5d313131333731 [ 2911.190844] x11: 00000000fffeffff x10: 00000000fffeffff x9 : ffffd1b78274a13c [ 2911.191716] x8 : 000000000017ffe8 x7 : c0000000fffeffff x6 : 000000000057ffa8 [ 2911.192554] x5 : ffff0012f6c24ec0 x4 : 0000000000000000 x3 : ffff2e5b72b5d000 [ 2911.193404] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0003ff254480 [ 2911.194259] Call trace: [ 2911.194626] tracing_map_sort_entries+0x3e0/0x408 [ 2911.195220] hist_show+0x124/0x800 [ 2911.195692] seq_read_iter+0x1d4/0x4e8 [ 2911.196193] seq_read+0xe8/0x138 [ 2911.196638] vfs_read+0xc8/0x300 [ 2911.197078] ksys_read+0x70/0x108 [ 2911.197534] __arm64_sys_read+0x24/0x38 [ 2911.198046] invoke_syscall+0x78/0x108 [ 2911.198553] el0_svc_common.constprop.0+0xd0/0xf8 [ 2911.199157] do_el0_svc+0x28/0x40 [ 2911.199613] el0_svc+0x40/0x178 [ 2911.200048] el0t_64_sync_handler+0x13c/0x158 [ 2911.200621] el0t_64_sync+0x1a8/0x1b0 [ 2911.201115] ---[ end trace 0000000000000000 ]--- The problem appears to be caused by CPU reordering of writes issued from __tracing_map_insert(). The check for the presence of an element with a given key in this function is: val = READ_ONCE(entry->val); if (val && keys_match(key, val->key, map->key_size)) ... The write of a new entry is: elt = get_free_elt(map); memcpy(elt->key, key, map->key_size); entry->val = elt; The "memcpy(elt->key, key, map->key_size);" and "entry->val = elt;" stores may become visible in the reversed order on another CPU. This second CPU might then incorrectly determine that a new key doesn't match an already present val->key and subsequently insert a new element, resulting in a duplicate. Fix the problem by adding a write barrier between "memcpy(elt->key, key, map->key_size);" and "entry->val = elt;", and for good measure, also use WRITE_ONCE(entry->val, elt) for publishing the element. The sequence pairs with the mentioned "READ_ONCE(entry->val);" and the "val->key" check which has an address dependency. The barrier is placed on a path executed when adding an element for a new key. Subsequent updates targeting the same key remain unaffected. From the user's perspective, the issue was introduced by commit c193707dde77 ("tracing: Remove code which merges duplicates"), which followed commit cbf4100efb8f ("tracing: Add support to detect and avoid duplicates"). The previous code operated differently; it inherently expected potential races which result in duplicates but merged them later when they occurred. Link: https://lore.kernel.org/linux-trace-kernel/20240122150928.27725-1-petr.pavl… Fixes: c193707dde77 ("tracing: Remove code which merges duplicates") Signed-off-by: Petr Pavlu <petr.pavlu(a)suse.com> Acked-by: Tom Zanussi <tom.zanussi(a)linux.intel.com> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> Signed-off-by: Zheng Yejian <zhengyejian1(a)huawei.com> --- kernel/trace/tracing_map.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c index 51a9d1185033..d47641f9740b 100644 --- a/kernel/trace/tracing_map.c +++ b/kernel/trace/tracing_map.c @@ -574,7 +574,12 @@ __tracing_map_insert(struct tracing_map *map, void *key, bool lookup_only) } memcpy(elt->key, key, map->key_size); - entry->val = elt; + /* + * Ensure the initialization is visible and + * publish the elt. + */ + smp_wmb(); + WRITE_ONCE(entry->val, elt); atomic64_inc(&map->hits); return entry->val; -- 2.17.1

2 1

[PATCH openEuler-22.03-LTS] netfilter: nf_tables: mark set as dead when unbinding anonymous set with timeout
by Guo Mengqi 14 May '24

14 May '24

From: Pablo Neira Ayuso <pablo(a)netfilter.org> mainline inclusion from mainline-v6.8 commit 552705a3650bbf46a22b1adedc1b04181490fc36 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9AK7L CVE: CVE-2024-26643 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… --------------------------- While the rhashtable set gc runs asynchronously, a race allows it to collect elements from anonymous sets with timeouts while it is being released from the commit path. Mingi Cho originally reported this issue in a different path in 6.1.x with a pipapo set with low timeouts which is not possible upstream since 7395dfacfff6 ("netfilter: nf_tables: use timestamp to check for set element timeout"). Fix this by setting on the dead flag for anonymous sets to skip async gc in this case. According to 08e4c8c5919f ("netfilter: nf_tables: mark newset as dead on transaction abort"), Florian plans to accelerate abort path by releasing objects via workqueue, therefore, this sets on the dead flag for abort path too. Cc: stable(a)vger.kernel.org Fixes: 5f68718b34a5 ("netfilter: nf_tables: GC transaction API to avoid race with control plane") Reported-by: Mingi Cho <mgcho.minic(a)gmail.com> Signed-off-by: Pablo Neira Ayuso <pablo(a)netfilter.org> Signed-off-by: Liu Jian <liujian56(a)huawei.com> --- net/netfilter/nf_tables_api.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c index 866a4ea8f4e7..c547d7beb6d1 100644 --- a/net/netfilter/nf_tables_api.c +++ b/net/netfilter/nf_tables_api.c @@ -4672,6 +4672,7 @@ static void nf_tables_unbind_set(const struct nft_ctx *ctx, struct nft_set *set, if (list_empty(&set->bindings) && nft_set_is_anonymous(set)) { list_del_rcu(&set->list); + set->dead = 1; if (event) nf_tables_set_notify(ctx, set, NFT_MSG_DELSET, GFP_KERNEL); -- 2.17.1

2 1

[PATCH openEuler-22.03-LTS-SP2] tracing: Ensure visibility when inserting an element into tracing_map
by Guo Mengqi 14 May '24

14 May '24

From: Petr Pavlu <petr.pavlu(a)suse.com> mainline inclusion from mainline-v6.8-rc2 commit 2b44760609e9eaafc9d234a6883d042fc21132a7 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9BV24 CVE: CVE-2024-26645 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -------------------------------- Running the following two commands in parallel on a multi-processor AArch64 machine can sporadically produce an unexpected warning about duplicate histogram entries: $ while true; do echo hist:key=id.syscall:val=hitcount > \ /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/trigger cat /sys/kernel/debug/tracing/events/raw_syscalls/sys_enter/hist sleep 0.001 done $ stress-ng --sysbadaddr $(nproc) The warning looks as follows: [ 2911.172474] ------------[ cut here ]------------ [ 2911.173111] Duplicates detected: 1 [ 2911.173574] WARNING: CPU: 2 PID: 12247 at kernel/trace/tracing_map.c:983 tracing_map_sort_entries+0x3e0/0x408 [ 2911.174702] Modules linked in: iscsi_ibft(E) iscsi_boot_sysfs(E) rfkill(E) af_packet(E) nls_iso8859_1(E) nls_cp437(E) vfat(E) fat(E) ena(E) tiny_power_button(E) qemu_fw_cfg(E) button(E) fuse(E) efi_pstore(E) ip_tables(E) x_tables(E) xfs(E) libcrc32c(E) aes_ce_blk(E) aes_ce_cipher(E) crct10dif_ce(E) polyval_ce(E) polyval_generic(E) ghash_ce(E) gf128mul(E) sm4_ce_gcm(E) sm4_ce_ccm(E) sm4_ce(E) sm4_ce_cipher(E) sm4(E) sm3_ce(E) sm3(E) sha3_ce(E) sha512_ce(E) sha512_arm64(E) sha2_ce(E) sha256_arm64(E) nvme(E) sha1_ce(E) nvme_core(E) nvme_auth(E) t10_pi(E) sg(E) scsi_mod(E) scsi_common(E) efivarfs(E) [ 2911.174738] Unloaded tainted modules: cppc_cpufreq(E):1 [ 2911.180985] CPU: 2 PID: 12247 Comm: cat Kdump: loaded Tainted: G E 6.7.0-default #2 1b58bbb22c97e4399dc09f92d309344f69c44a01 [ 2911.182398] Hardware name: Amazon EC2 c7g.8xlarge/, BIOS 1.0 11/1/2018 [ 2911.183208] pstate: 61400005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--) [ 2911.184038] pc : tracing_map_sort_entries+0x3e0/0x408 [ 2911.184667] lr : tracing_map_sort_entries+0x3e0/0x408 [ 2911.185310] sp : ffff8000a1513900 [ 2911.185750] x29: ffff8000a1513900 x28: ffff0003f272fe80 x27: 0000000000000001 [ 2911.186600] x26: ffff0003f272fe80 x25: 0000000000000030 x24: 0000000000000008 [ 2911.187458] x23: ffff0003c5788000 x22: ffff0003c16710c8 x21: ffff80008017f180 [ 2911.188310] x20: ffff80008017f000 x19: ffff80008017f180 x18: ffffffffffffffff [ 2911.189160] x17: 0000000000000000 x16: 0000000000000000 x15: ffff8000a15134b8 [ 2911.190015] x14: 0000000000000000 x13: 205d373432323154 x12: 5b5d313131333731 [ 2911.190844] x11: 00000000fffeffff x10: 00000000fffeffff x9 : ffffd1b78274a13c [ 2911.191716] x8 : 000000000017ffe8 x7 : c0000000fffeffff x6 : 000000000057ffa8 [ 2911.192554] x5 : ffff0012f6c24ec0 x4 : 0000000000000000 x3 : ffff2e5b72b5d000 [ 2911.193404] x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0003ff254480 [ 2911.194259] Call trace: [ 2911.194626] tracing_map_sort_entries+0x3e0/0x408 [ 2911.195220] hist_show+0x124/0x800 [ 2911.195692] seq_read_iter+0x1d4/0x4e8 [ 2911.196193] seq_read+0xe8/0x138 [ 2911.196638] vfs_read+0xc8/0x300 [ 2911.197078] ksys_read+0x70/0x108 [ 2911.197534] __arm64_sys_read+0x24/0x38 [ 2911.198046] invoke_syscall+0x78/0x108 [ 2911.198553] el0_svc_common.constprop.0+0xd0/0xf8 [ 2911.199157] do_el0_svc+0x28/0x40 [ 2911.199613] el0_svc+0x40/0x178 [ 2911.200048] el0t_64_sync_handler+0x13c/0x158 [ 2911.200621] el0t_64_sync+0x1a8/0x1b0 [ 2911.201115] ---[ end trace 0000000000000000 ]--- The problem appears to be caused by CPU reordering of writes issued from __tracing_map_insert(). The check for the presence of an element with a given key in this function is: val = READ_ONCE(entry->val); if (val && keys_match(key, val->key, map->key_size)) ... The write of a new entry is: elt = get_free_elt(map); memcpy(elt->key, key, map->key_size); entry->val = elt; The "memcpy(elt->key, key, map->key_size);" and "entry->val = elt;" stores may become visible in the reversed order on another CPU. This second CPU might then incorrectly determine that a new key doesn't match an already present val->key and subsequently insert a new element, resulting in a duplicate. Fix the problem by adding a write barrier between "memcpy(elt->key, key, map->key_size);" and "entry->val = elt;", and for good measure, also use WRITE_ONCE(entry->val, elt) for publishing the element. The sequence pairs with the mentioned "READ_ONCE(entry->val);" and the "val->key" check which has an address dependency. The barrier is placed on a path executed when adding an element for a new key. Subsequent updates targeting the same key remain unaffected. From the user's perspective, the issue was introduced by commit c193707dde77 ("tracing: Remove code which merges duplicates"), which followed commit cbf4100efb8f ("tracing: Add support to detect and avoid duplicates"). The previous code operated differently; it inherently expected potential races which result in duplicates but merged them later when they occurred. Link: https://lore.kernel.org/linux-trace-kernel/20240122150928.27725-1-petr.pavl… Fixes: c193707dde77 ("tracing: Remove code which merges duplicates") Signed-off-by: Petr Pavlu <petr.pavlu(a)suse.com> Acked-by: Tom Zanussi <tom.zanussi(a)linux.intel.com> Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> Signed-off-by: Zheng Yejian <zhengyejian1(a)huawei.com> --- kernel/trace/tracing_map.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c index 51a9d1185033..d47641f9740b 100644 --- a/kernel/trace/tracing_map.c +++ b/kernel/trace/tracing_map.c @@ -574,7 +574,12 @@ __tracing_map_insert(struct tracing_map *map, void *key, bool lookup_only) } memcpy(elt->key, key, map->key_size); - entry->val = elt; + /* + * Ensure the initialization is visible and + * publish the elt. + */ + smp_wmb(); + WRITE_ONCE(entry->val, elt); atomic64_inc(&map->hits); return entry->val; -- 2.17.1

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