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CVE-2021-47546— ipv6: fix memory leak in fib6_rule_suppress

EPSS 0.01% · P3
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I. Basic Information for CVE-2021-47546

Vulnerability Information
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Vulnerability Title
ipv6: fix memory leak in fib6_rule_suppress
Source: NVD (National Vulnerability Database)
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ipv6: fix memory leak in fib6_rule_suppress The kernel leaks memory when a `fib` rule is present in IPv6 nftables firewall rules and a suppress_prefix rule is present in the IPv6 routing rules (used by certain tools such as wg-quick). In such scenarios, every incoming packet will leak an allocation in `ip6_dst_cache` slab cache. After some hours of `bpftrace`-ing and source code reading, I tracked down the issue to ca7a03c41753 ("ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule"). The problem with that change is that the generic `args->flags` always have `FIB_LOOKUP_NOREF` set[1][2] but the IPv6-specific flag `RT6_LOOKUP_F_DST_NOREF` might not be, leading to `fib6_rule_suppress` not decreasing the refcount when needed. How to reproduce: - Add the following nftables rule to a prerouting chain: meta nfproto ipv6 fib saddr . mark . iif oif missing drop This can be done with: sudo nft create table inet test sudo nft create chain inet test test_chain '{ type filter hook prerouting priority filter + 10; policy accept; }' sudo nft add rule inet test test_chain meta nfproto ipv6 fib saddr . mark . iif oif missing drop - Run: sudo ip -6 rule add table main suppress_prefixlength 0 - Watch `sudo slabtop -o | grep ip6_dst_cache` to see memory usage increase with every incoming ipv6 packet. This patch exposes the protocol-specific flags to the protocol specific `suppress` function, and check the protocol-specific `flags` argument for RT6_LOOKUP_F_DST_NOREF instead of the generic FIB_LOOKUP_NOREF when decreasing the refcount, like this. [1]: https://github.com/torvalds/linux/blob/ca7a03c4175366a92cee0ccc4fec0038c3266e26/net/ipv6/fib6_rules.c#L71 [2]: https://github.com/torvalds/linux/blob/ca7a03c4175366a92cee0ccc4fec0038c3266e26/net/ipv6/fib6_rules.c#L99
Source: NVD (National Vulnerability Database)
CVSS Information
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Type
N/A
Source: NVD (National Vulnerability Database)
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于存在内存泄漏。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

VendorProductAffected VersionsCPESubscribe
LinuxLinux ca7a03c4175366a92cee0ccc4fec0038c3266e26 ~ ee38eb8cf9a7323884c2b8e0adbbeb2192d31e29 -
LinuxLinux 5.4 -

II. Public POCs for CVE-2021-47546

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III. Intelligence Information for CVE-2021-47546

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Same Patch Batch · Linux · 2024-05-24 · 73 CVEs total

CVE-2021-47549sata_fsl: fix UAF in sata_fsl_port_stop when rmmod sata_fsl
CVE-2021-47569io_uring: fail cancellation for EXITING tasks
CVE-2021-47567powerpc/32: Fix hardlockup on vmap stack overflow
CVE-2021-47554vdpa_sim: avoid putting an uninitialized iova_domain
CVE-2021-47555net: vlan: fix underflow for the real_dev refcnt
CVE-2021-47553sched/scs: Reset task stack state in bringup_cpu()
CVE-2021-47551drm/amd/amdkfd: Fix kernel panic when reset failed and been triggered again
CVE-2021-47552blk-mq: cancel blk-mq dispatch work in both blk_cleanup_queue and disk_release()
CVE-2021-47550drm/amd/amdgpu: fix potential memleak
CVE-2021-47548ethernet: hisilicon: hns: hns_dsaf_misc: fix a possible array overflow in hns_dsaf_ge_srst
CVE-2021-47556ethtool: ioctl: fix potential NULL deref in ethtool_set_coalesce()
CVE-2021-47547net: tulip: de4x5: fix the problem that the array 'lp->phy[8]' may be out of bound
CVE-2021-47544tcp: fix page frag corruption on page fault
CVE-2021-47542net: qlogic: qlcnic: Fix a NULL pointer dereference in qlcnic_83xx_add_rings()
CVE-2021-47541net/mlx4_en: Fix an use-after-free bug in mlx4_en_try_alloc_resources()
CVE-2021-47540mt76: mt7915: fix NULL pointer dereference in mt7915_get_phy_mode
CVE-2021-47539rxrpc: Fix rxrpc_peer leak in rxrpc_look_up_bundle()
CVE-2021-47538rxrpc: Fix rxrpc_local leak in rxrpc_lookup_peer()
CVE-2021-47536net/smc: fix wrong list_del in smc_lgr_cleanup_early
CVE-2021-47537octeontx2-af: Fix a memleak bug in rvu_mbox_init()

Showing top 20 of 73 CVEs. View all on vendor page → →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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