CVSS: 5.5EPSS: 0%CPEs: 6EXPL: 0CVE-2021-47546 – ipv6: fix memory leak in fib6_rule_suppress
https://notcve.org/view.php?id=CVE-2021-47546
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 En el kernel de Linux, se resolvió la siguiente vulnerabilidad: ipv6: corrige la pérdida de memoria en fib6_rule_suppress El kernel pierde memoria cuando una regla `fib` está presente en las reglas de firewall de nftables de IPv6 y una regla de supresión_prefix está presente en las reglas de enrutamiento de IPv6 (utilizadas por ciertas herramientas como wg-quick). En tales escenarios, cada paquete entrante perderá una asignación en el caché de losa `ip6_dst_cache`. Después de algunas horas de `bpftrace`-ing y lectura del código fuente, rastreé el problema hasta ca7a03c41753 ("ipv6: no libere rt si FIB_LOOKUP_NOREF está configurado en la regla de supresión"). El problema con ese cambio es que los `args->flags` genéricos siempre tienen `FIB_LOOKUP_NOREF` configurado[1][2] pero el indicador específico de IPv6 `RT6_LOOKUP_F_DST_NOREF` podría no estarlo, lo que lleva a que `fib6_rule_suppress` no disminuya el recuento cuando necesario. • https://git.kernel.org/stable/c/ca7a03c4175366a92cee0ccc4fec0038c3266e26 https://git.kernel.org/stable/c/d37c966752043733eb847dd897d6e3405084c559 https://git.kernel.org/stable/c/ecc265624956ea784cb2bd2b31a95bd54c4f5f13 https://git.kernel.org/stable/c/ee38eb8cf9a7323884c2b8e0adbbeb2192d31e29 https://git.kernel.org/stable/c/209d35ee34e25f9668c404350a1c86d914c54ffa https://git.kernel.org/stable/c/8ef8a76a340ebdb2c2eea3f6fb0ebbed09a16383 https://git.kernel.org/stable/c/cdef485217d30382f3bf6448c54b4401648fe3f1 • CWE-401: Missing Release of Memory after Effective Lifetime •
CVSS: 6.3EPSS: 0%CPEs: 3EXPL: 0CVE-2021-47544 – tcp: fix page frag corruption on page fault
https://notcve.org/view.php?id=CVE-2021-47544
In the Linux kernel, the following vulnerability has been resolved: tcp: fix page frag corruption on page fault Steffen reported a TCP stream corruption for HTTP requests served by the apache web-server using a cifs mount-point and memory mapping the relevant file. The root cause is quite similar to the one addressed by commit 20eb4f29b602 ("net: fix sk_page_frag() recursion from memory reclaim"). Here the nested access to the task page frag is caused by a page fault on the (mmapped) user-space memory buffer coming from the cifs file. The page fault handler performs an smb transaction on a different socket, inside the same process context. Since sk->sk_allaction for such socket does not prevent the usage for the task_frag, the nested allocation modify "under the hood" the page frag in use by the outer sendmsg call, corrupting the stream. The overall relevant stack trace looks like the following: httpd 78268 [001] 3461630.850950: probe:tcp_sendmsg_locked: ffffffff91461d91 tcp_sendmsg_locked+0x1 ffffffff91462b57 tcp_sendmsg+0x27 ffffffff9139814e sock_sendmsg+0x3e ffffffffc06dfe1d smb_send_kvec+0x28 [...] ffffffffc06cfaf8 cifs_readpages+0x213 ffffffff90e83c4b read_pages+0x6b ffffffff90e83f31 __do_page_cache_readahead+0x1c1 ffffffff90e79e98 filemap_fault+0x788 ffffffff90eb0458 __do_fault+0x38 ffffffff90eb5280 do_fault+0x1a0 ffffffff90eb7c84 __handle_mm_fault+0x4d4 ffffffff90eb8093 handle_mm_fault+0xc3 ffffffff90c74f6d __do_page_fault+0x1ed ffffffff90c75277 do_page_fault+0x37 ffffffff9160111e page_fault+0x1e ffffffff9109e7b5 copyin+0x25 ffffffff9109eb40 _copy_from_iter_full+0xe0 ffffffff91462370 tcp_sendmsg_locked+0x5e0 ffffffff91462370 tcp_sendmsg_locked+0x5e0 ffffffff91462b57 tcp_sendmsg+0x27 ffffffff9139815c sock_sendmsg+0x4c ffffffff913981f7 sock_write_iter+0x97 ffffffff90f2cc56 do_iter_readv_writev+0x156 ffffffff90f2dff0 do_iter_write+0x80 ffffffff90f2e1c3 vfs_writev+0xa3 ffffffff90f2e27c do_writev+0x5c ffffffff90c042bb do_syscall_64+0x5b ffffffff916000ad entry_SYSCALL_64_after_hwframe+0x65 The cifs filesystem rightfully sets sk_allocations to GFP_NOFS, we can avoid the nesting using the sk page frag for allocation lacking the __GFP_FS flag. Do not define an additional mm-helper for that, as this is strictly tied to the sk page frag usage. v1 -> v2: - use a stricted sk_page_frag() check instead of reordering the code (Eric) En el kernel de Linux, se resolvió la siguiente vulnerabilidad: tcp: corregir corrupción de fragmentos de página en falla de página Steffen informó una corrupción de flujo TCP para solicitudes HTTP atendidas por el servidor web Apache usando un punto de montaje cifs y mapeando la memoria del archivo relevante. La causa raíz es bastante similar a la abordada por el commit 20eb4f29b602 ("net: fix sk_page_frag() recursividad desde la recuperación de memoria"). • https://git.kernel.org/stable/c/5640f7685831e088fe6c2e1f863a6805962f8e81 https://git.kernel.org/stable/c/c6f340a331fb72e5ac23a083de9c780e132ca3ae https://git.kernel.org/stable/c/5a9afcd827cafe14a95c9fcbded2c2d104f18dfc https://git.kernel.org/stable/c/dacb5d8875cc6cd3a553363b4d6f06760fcbe70c https://access.redhat.com/security/cve/CVE-2021-47544 https://bugzilla.redhat.com/show_bug.cgi?id=2283406 • CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer •
CVSS: 5.5EPSS: 0%CPEs: 8EXPL: 0CVE-2021-47542 – net: qlogic: qlcnic: Fix a NULL pointer dereference in qlcnic_83xx_add_rings()
https://notcve.org/view.php?id=CVE-2021-47542
In the Linux kernel, the following vulnerability has been resolved: net: qlogic: qlcnic: Fix a NULL pointer dereference in qlcnic_83xx_add_rings() In qlcnic_83xx_add_rings(), the indirect function of ahw->hw_ops->alloc_mbx_args will be called to allocate memory for cmd.req.arg, and there is a dereference of it in qlcnic_83xx_add_rings(), which could lead to a NULL pointer dereference on failure of the indirect function like qlcnic_83xx_alloc_mbx_args(). Fix this bug by adding a check of alloc_mbx_args(), this patch imitates the logic of mbx_cmd()'s failure handling. This bug was found by a static analyzer. The analysis employs differential checking to identify inconsistent security operations (e.g., checks or kfrees) between two code paths and confirms that the inconsistent operations are not recovered in the current function or the callers, so they constitute bugs. Note that, as a bug found by static analysis, it can be a false positive or hard to trigger. Multiple researchers have cross-reviewed the bug. Builds with CONFIG_QLCNIC=m show no new warnings, and our static analyzer no longer warns about this code. En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net: qlogic: qlcnic: corrigió una desreferencia de puntero NULL en qlcnic_83xx_add_rings() En qlcnic_83xx_add_rings(), se llamará a la función indirecta de ahw->hw_ops->alloc_mbx_args para asignar memoria para cmd.req.arg, y hay una desreferencia del mismo en qlcnic_83xx_add_rings(), lo que podría llevar a una desreferencia del puntero NULL en caso de falla de la función indirecta como qlcnic_83xx_alloc_mbx_args(). Corrija este error agregando una verificación de alloc_mbx_args(); este parche imita la lógica del manejo de fallas de mbx_cmd(). • https://git.kernel.org/stable/c/7f9664525f9cb507de9198a395a111371413f230 https://git.kernel.org/stable/c/3a061d54e260b701b538873b43e399d9b8b83e03 https://git.kernel.org/stable/c/b4f217d6fcc00c3fdc0921a7691f30be7490b073 https://git.kernel.org/stable/c/550658a2d61e4eaf522c8ebc7fad76dc376bfb45 https://git.kernel.org/stable/c/57af54a56024435d83e44c78449513b414eb6edf https://git.kernel.org/stable/c/bbeb0325a7460ebf1e03f5e0bfc5c652fba9519f https://git.kernel.org/stable/c/15fa12c119f869173f9b710cbe6a4a14071d2105 https://git.kernel.org/stable/c/c5ef33c1489b2cd74368057fa00b5d218 • CWE-476: NULL Pointer Dereference •
CVSS: 7.8EPSS: 0%CPEs: 6EXPL: 0CVE-2021-47541 – net/mlx4_en: Fix an use-after-free bug in mlx4_en_try_alloc_resources()
https://notcve.org/view.php?id=CVE-2021-47541
In the Linux kernel, the following vulnerability has been resolved: net/mlx4_en: Fix an use-after-free bug in mlx4_en_try_alloc_resources() In mlx4_en_try_alloc_resources(), mlx4_en_copy_priv() is called and tmp->tx_cq will be freed on the error path of mlx4_en_copy_priv(). After that mlx4_en_alloc_resources() is called and there is a dereference of &tmp->tx_cq[t][i] in mlx4_en_alloc_resources(), which could lead to a use after free problem on failure of mlx4_en_copy_priv(). Fix this bug by adding a check of mlx4_en_copy_priv() This bug was found by a static analyzer. The analysis employs differential checking to identify inconsistent security operations (e.g., checks or kfrees) between two code paths and confirms that the inconsistent operations are not recovered in the current function or the callers, so they constitute bugs. Note that, as a bug found by static analysis, it can be a false positive or hard to trigger. Multiple researchers have cross-reviewed the bug. Builds with CONFIG_MLX4_EN=m show no new warnings, and our static analyzer no longer warns about this code. En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: net/mlx4_en: corrige un error de use-after-free en mlx4_en_try_alloc_resources() En mlx4_en_try_alloc_resources(), se llama a mlx4_en_copy_priv() y se liberará tmp->tx_cq en la ruta del error de mlx4_en_copy_priv(). Después de eso, se llama a mlx4_en_alloc_resources() y hay una desreferencia de &tmp->tx_cq[t][i] en mlx4_en_alloc_resources(), lo que podría llevar a un problema de use-after-free si falla mlx4_en_copy_priv(). • https://git.kernel.org/stable/c/ec25bc04ed8e12947738468cbe2191f1529f9e39 https://git.kernel.org/stable/c/be12572c5ddc8ad7453bada4eec8fa46967dc757 https://git.kernel.org/stable/c/676dc7d9b15bf8733233a2db1ec3f9091ab34275 https://git.kernel.org/stable/c/e461a9816a1ac5b4aeb61621b817225b61e46a68 https://git.kernel.org/stable/c/f1d43efa59f1edd3e7eca0e94559b4c6b1cd4e2b https://git.kernel.org/stable/c/75917372eef0dbfb290ae45474314d35f97aea18 https://git.kernel.org/stable/c/addad7643142f500080417dd7272f49b7a185570 • CWE-416: Use After Free •
CVSS: -EPSS: 0%CPEs: 6EXPL: 0CVE-2021-47538 – rxrpc: Fix rxrpc_local leak in rxrpc_lookup_peer()
https://notcve.org/view.php?id=CVE-2021-47538
In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix rxrpc_local leak in rxrpc_lookup_peer() Need to call rxrpc_put_local() for peer candidate before kfree() as it holds a ref to rxrpc_local. [DH: v2: Changed to abstract the peer freeing code out into a function] En el kernel de Linux, se resolvió la siguiente vulnerabilidad: rxrpc: corrigió la fuga de rxrpc_local en rxrpc_lookup_peer() Es necesario llamar a rxrpc_put_local() para el candidato par antes de kfree(), ya que contiene una referencia a rxrpc_local. [DH: v2: modificado para abstraer el código de liberación del par en una función] • https://git.kernel.org/stable/c/e8e51ce79c157188e209e5ea0afaf6b42dd76104 https://git.kernel.org/stable/c/9ebeddef58c41bd700419cdcece24cf64ce32276 https://git.kernel.org/stable/c/9b7fc03b4cdbfb668b6891967105258691c6d3b5 https://git.kernel.org/stable/c/913c24af2d13a3fd304462916ee98e298d56bdce https://git.kernel.org/stable/c/3e70e3a72d80b16094faccbe438cd53761c3503a https://git.kernel.org/stable/c/60f0b9c42cb80833a03ca57c1c8b078d716e71d1 https://git.kernel.org/stable/c/9469273e616ca8f1b6e3773c5019f21b4c8d828c https://git.kernel.org/stable/c/beacff50edbd6c9659a6f15fc7f612690 •