CVSS: 5.5EPSS: 0%CPEs: 6EXPL: 0CVE-2021-46935 – binder: fix async_free_space accounting for empty parcels
https://notcve.org/view.php?id=CVE-2021-46935
In the Linux kernel, the following vulnerability has been resolved: binder: fix async_free_space accounting for empty parcels In 4.13, commit 74310e06be4d ("android: binder: Move buffer out of area shared with user space") fixed a kernel structure visibility issue. As part of that patch, sizeof(void *) was used as the buffer size for 0-length data payloads so the driver could detect abusive clients sending 0-length asynchronous transactions to a server by enforcing limits on async_free_size. Unfortunately, on the "free" side, the accounting of async_free_space did not add the sizeof(void *) back. The result was that up to 8-bytes of async_free_space were leaked on every async transaction of 8-bytes or less. These small transactions are uncommon, so this accounting issue has gone undetected for several years. The fix is to use "buffer_size" (the allocated buffer size) instead of "size" (the logical buffer size) when updating the async_free_space during the free operation. These are the same except for this corner case of asynchronous transactions with payloads < 8 bytes. • https://git.kernel.org/stable/c/74310e06be4d74dcf67cd108366710dee5c576d5 https://git.kernel.org/stable/c/2d2df539d05205fd83c404d5f2dff48d36f9b495 https://git.kernel.org/stable/c/7c7064402609aeb6fb11be1b4ec10673ff17b593 https://git.kernel.org/stable/c/103b16a8c51f96d5fe063022869ea906c256e5da https://git.kernel.org/stable/c/1cb8444f3114f0bb2f6e3bcadcf09aa4a28425d4 https://git.kernel.org/stable/c/17691bada6b2f1d5f1c0f6d28cd9d0727023b0ff https://git.kernel.org/stable/c/cfd0d84ba28c18b531648c9d4a35ecca89ad9901 • CWE-668: Exposure of Resource to Wrong Sphere •
CVSS: 5.5EPSS: 0%CPEs: 8EXPL: 0CVE-2021-46933 – usb: gadget: f_fs: Clear ffs_eventfd in ffs_data_clear.
https://notcve.org/view.php?id=CVE-2021-46933
In the Linux kernel, the following vulnerability has been resolved: usb: gadget: f_fs: Clear ffs_eventfd in ffs_data_clear. ffs_data_clear is indirectly called from both ffs_fs_kill_sb and ffs_ep0_release, so it ends up being called twice when userland closes ep0 and then unmounts f_fs. If userland provided an eventfd along with function's USB descriptors, it ends up calling eventfd_ctx_put as many times, causing a refcount underflow. NULL-ify ffs_eventfd to prevent these extraneous eventfd_ctx_put calls. Also, set epfiles to NULL right after de-allocating it, for readability. For completeness, ffs_data_clear actually ends up being called thrice, the last call being before the whole ffs structure gets freed, so when this specific sequence happens there is a second underflow happening (but not being reported): /sys/kernel/debug/tracing# modprobe usb_f_fs /sys/kernel/debug/tracing# echo ffs_data_clear > set_ftrace_filter /sys/kernel/debug/tracing# echo function > current_tracer /sys/kernel/debug/tracing# echo 1 > tracing_on (setup gadget, run and kill function userland process, teardown gadget) /sys/kernel/debug/tracing# echo 0 > tracing_on /sys/kernel/debug/tracing# cat trace smartcard-openp-436 [000] ..... 1946.208786: ffs_data_clear <-ffs_data_closed smartcard-openp-431 [000] ..... 1946.279147: ffs_data_clear <-ffs_data_closed smartcard-openp-431 [000] .n... 1946.905512: ffs_data_clear <-ffs_data_put Warning output corresponding to above trace: [ 1946.284139] WARNING: CPU: 0 PID: 431 at lib/refcount.c:28 refcount_warn_saturate+0x110/0x15c [ 1946.293094] refcount_t: underflow; use-after-free. [ 1946.298164] Modules linked in: usb_f_ncm(E) u_ether(E) usb_f_fs(E) hci_uart(E) btqca(E) btrtl(E) btbcm(E) btintel(E) bluetooth(E) nls_ascii(E) nls_cp437(E) vfat(E) fat(E) bcm2835_v4l2(CE) bcm2835_mmal_vchiq(CE) videobuf2_vmalloc(E) videobuf2_memops(E) sha512_generic(E) videobuf2_v4l2(E) sha512_arm(E) videobuf2_common(E) videodev(E) cpufreq_dt(E) snd_bcm2835(CE) brcmfmac(E) mc(E) vc4(E) ctr(E) brcmutil(E) snd_soc_core(E) snd_pcm_dmaengine(E) drbg(E) snd_pcm(E) snd_timer(E) snd(E) soundcore(E) drm_kms_helper(E) cec(E) ansi_cprng(E) rc_core(E) syscopyarea(E) raspberrypi_cpufreq(E) sysfillrect(E) sysimgblt(E) cfg80211(E) max17040_battery(OE) raspberrypi_hwmon(E) fb_sys_fops(E) regmap_i2c(E) ecdh_generic(E) rfkill(E) ecc(E) bcm2835_rng(E) rng_core(E) vchiq(CE) leds_gpio(E) libcomposite(E) fuse(E) configfs(E) ip_tables(E) x_tables(E) autofs4(E) ext4(E) crc16(E) mbcache(E) jbd2(E) crc32c_generic(E) sdhci_iproc(E) sdhci_pltfm(E) sdhci(E) [ 1946.399633] CPU: 0 PID: 431 Comm: smartcard-openp Tainted: G C OE 5.15.0-1-rpi #1 Debian 5.15.3-1 [ 1946.417950] Hardware name: BCM2835 [ 1946.425442] Backtrace: [ 1946.432048] [<c08d60a0>] (dump_backtrace) from [<c08d62ec>] (show_stack+0x20/0x24) [ 1946.448226] r7:00000009 r6:0000001c r5:c04a948c r4:c0a64e2c [ 1946.458412] [<c08d62cc>] (show_stack) from [<c08d9ae0>] (dump_stack+0x28/0x30) [ 1946.470380] [<c08d9ab8>] (dump_stack) from [<c0123500>] (__warn+0xe8/0x154) [ 1946.482067] r5:c04a948c r4:c0a71dc8 [ 1946.490184] [<c0123418>] (__warn) from [<c08d6948>] (warn_slowpath_fmt+0xa0/0xe4) [ 1946.506758] r7:00000009 r6:0000001c r5:c0a71dc8 r4:c0a71e04 [ 1946.517070] [<c08d68ac>] (warn_slowpath_fmt) from [<c04a948c>] (refcount_warn_saturate+0x110/0x15c) [ 1946.535309] r8:c0100224 r7:c0dfcb84 r6:ffffffff r5:c3b84c00 r4:c24a17c0 [ 1946.546708] [<c04a937c>] (refcount_warn_saturate) from [<c0380134>] (eventfd_ctx_put+0x48/0x74) [ 1946.564476] [<c03800ec>] (eventfd_ctx_put) from [<bf5464e8>] (ffs_data_clear+0xd0/0x118 [usb_f_fs]) [ 1946.582664] r5:c3b84c00 r4:c2695b00 [ 1946.590668] [<bf546418>] (ffs_data_clear [usb_f_fs]) from [<bf547cc0>] (ffs_data_closed+0x9c/0x150 [usb_f_fs]) [ 1946.609608] r5:bf54d014 r4:c2695b00 [ 1946.617522] [<bf547c24>] (ffs_data_closed [usb_f_fs]) from [<bf547da0>] (ffs_fs_kill_sb+0x2c/0x30 [usb_f_fs]) [ 1946.636217] r7:c0dfcb ---truncated--- En el kernel de Linux se ha resuelto la siguiente vulnerabilidad: usb: gadget: f_fs: Borrar ffs_eventfd en ffs_data_clear. ffs_data_clear se llama indirectamente desde ffs_fs_kill_sb y ffs_ep0_release, por lo que termina siendo llamado dos veces cuando el área de usuario cierra ep0 y luego desmonta f_fs. Si Userland proporcionó un eventfd junto con los descriptores USB de la función, termina llamando a eventfd_ctx_put tantas veces, provocando un desbordamiento insuficiente de recuento. NULL-ify ffs_eventfd para evitar estas llamadas extrañas eventfd_ctx_put. Además, establezca epfiles en NULL justo después de desasignarlo, para facilitar la lectura. Para completar, ffs_data_clear en realidad termina siendo llamado tres veces, la última llamada es antes de que se libere toda la estructura de ffs, por lo que cuando ocurre esta secuencia específica, se produce un segundo desbordamiento insuficiente (pero no se informa): /sys/kernel/debug/tracing # modprobe usb_f_fs /sys/kernel/debug/tracing# echo ffs_data_clear > set_ftrace_filter /sys/kernel/debug/tracing# echo function > current_tracer /sys/kernel/debug/tracing# echo 1 > tracing_on (dispositivo de configuración, función ejecutar y finalizar proceso de usuario, dispositivo de desmontaje) /sys/kernel/debug/tracing# echo 0 > tracing_on /sys/kernel/debug/tracing# cat trace smartcard-openp-436 [000] ..... 1946.208786: ffs_data_clear <-ffs_data_closed tarjeta inteligente -openp-431 [000] ..... 1946.279147: ffs_data_clear <-ffs_data_closed smartcard-openp-431 [000] .n... 1946.905512: ffs_data_clear <-ffs_data_put Salida de advertencia correspondiente al seguimiento anterior: [ 1946.284139] ADVERTENCIA: CPU : 0 PID: 431 en lib/refcount.c:28 refcount_warn_saturate+0x110/0x15c [ 1946.293094] refcount_t: desbordamiento insuficiente; use-after-free. [1946.298164] Módulos vinculados en: usb_f_ncm(E) u_ether(E) usb_f_fs(E) hci_uart(E) btqca(E) btrtl(E) btbcm(E) btintel(E) bluetooth(E) nls_ascii(E) nls_cp437(E ) vfat(E) fat(E) bcm2835_v4l2(CE) bcm2835_mmal_vchiq(CE) videobuf2_vmalloc(E) videobuf2_memops(E) sha512_generic(E) videobuf2_v4l2(E) sha512_arm(E) videobuf2_common(E) videodev(E) cpufreq_dt(E) snd_b cm2835 (CE) brcmfmac(E) mc(E) vc4(E) ctr(E) brcmutil(E) snd_soc_core(E) snd_pcm_dmaengine(E) drbg(E) snd_pcm(E) snd_timer(E) snd(E) soundcore(E ) drm_kms_helper(E) cec(E) ansi_cprng(E) rc_core(E) syscopyarea(E) raspberrypi_cpufreq(E) sysfillrect(E) sysimgblt(E) cfg80211(E) max17040_battery(OE) raspberrypi_hwmon(E) fb_sys_fops(E) regmap_i2c (E) ecdh_generic(E) rfkill(E) ecc(E) bcm2835_rng(E) rng_core(E) vchiq(CE) leds_gpio(E) libcomposite(E) fuse(E) configfs(E) ip_tables(E) x_tables(E ) autofs4(E) ext4(E) crc16(E) mbcache(E) jbd2(E) crc32c_generic(E) sdhci_iproc(E) sdhci_pltfm(E) sdhci(E) [ 1946.399633] CPU: 0 PID: 431 Comm: tarjeta inteligente- openp Contaminado: GC OE 5.15.0-1-rpi #1 Debian 5.15.3-1 [ 1946.417950] Nombre de hardware: BCM2835 [ 1946.425442] Seguimiento inverso: [ 1946.432048] [] (dump_backtrace) de [] ( show_stack+0x20/0x24) [ 1946.448226] r7:00000009 r6:0000001c r5:c04a948c r4:c0a64e2c [ 1946.458412] [] (show_stack) de [] (dump_ pila+0x28/0x30) [ 1946.470380] [< c08d9ab8>] (dump_stack) de [] (__warn+0xe8/0x154) [ 1946.482067] r5:c04a948c r4:c0a71dc8 [ 1946.490184] [] (__warn) de [] (warn_slowpath_fmt+0xa0/ 0xe4) [ 1946.506758] r7:00000009 r6:0000001c r5:c0a71dc8 r4:c0a71e04 [ 1946.517070] [] (warn_slowpath_fmt) de [] (refcount_war n_saturado+0x110/0x15c) [ 1946.535309] r8:c0100224 r7:c0dfcb84 r6:ffffffff r5:c3b84c00 r4:c24a17c0 [ 1946.546708] [] (refcount_warn_saturate) de [] (eventfd_ctx_put+0x48/0x74) [ 1946.564476] [] (eventfd_ctx_put) de [] (ffs_data_clear+0xd0/0x118 [usb_f_fs]) [ 1946.582664] r5:c3b84c00 r4:c2695b00 [ 1946.590668] [] (ffs_data_clear [usb_f_fs]) de [] ( ffs_data_closed+0x9c/0x150 [usb_f_fs]) [ 1946.609608] r5:bf54d014 r4:c2695b00 [ 1946.617522] [] (ffs_data_closed [usb_f_fs • https://git.kernel.org/stable/c/5e33f6fdf735cda1d4580fe6f1878da05718fe73 https://git.kernel.org/stable/c/f976dd7011150244a7ba820f2c331e9fb253befa https://git.kernel.org/stable/c/cc8c8028c21b2a3842a1e98e99e55028df275919 https://git.kernel.org/stable/c/52500239e3f2d6fc77b6f58632a9fb98fe74ac09 https://git.kernel.org/stable/c/33f6a0cbb7772146e1c11f38028fffbfed14728b https://git.kernel.org/stable/c/240fc586e83d645912accce081a48aa63a45f6ee https://git.kernel.org/stable/c/1c4ace3e6b8575745c50dca9e76e0021e697d645 https://git.kernel.org/stable/c/ebef2aa29f370b5096c16020c104e3931 • CWE-416: Use After Free •
CVSS: 5.5EPSS: 0%CPEs: 8EXPL: 0CVE-2021-46932 – Input: appletouch - initialize work before device registration
https://notcve.org/view.php?id=CVE-2021-46932
In the Linux kernel, the following vulnerability has been resolved: Input: appletouch - initialize work before device registration Syzbot has reported warning in __flush_work(). This warning is caused by work->func == NULL, which means missing work initialization. This may happen, since input_dev->close() calls cancel_work_sync(&dev->work), but dev->work initalization happens _after_ input_register_device() call. So this patch moves dev->work initialization before registering input device En el kernel de Linux, se resolvió la siguiente vulnerabilidad: Entrada: appletouch: inicializa el trabajo antes del registro del dispositivo Syzbot ha informado una advertencia en __flush_work(). Esta advertencia es causada por work->func == NULL, lo que significa que falta la inicialización del trabajo. Esto puede suceder, ya que input_dev->close() llama a cancel_work_sync(&dev->work), pero la inicialización dev->work ocurre _después_ de la llamada input_register_device(). Entonces este parche mueve la inicialización dev->work antes de registrar el dispositivo de entrada • https://git.kernel.org/stable/c/5a6eb676d3bc4d7a6feab200a92437b62ad298da https://git.kernel.org/stable/c/d2cb2bf39a6d17ef4bdc0e59c1a35cf5751ad8f4 https://git.kernel.org/stable/c/d1962f263a176f493400b8f91bfbf2bfedce951e https://git.kernel.org/stable/c/292d2ac61fb0d9276a0f7b7ce4f50426f2a1c99f https://git.kernel.org/stable/c/a02e1404e27855089d2b0a0acc4652c2ce65fe46 https://git.kernel.org/stable/c/975774ea7528b489930b76a77ffc4d5379b95ff2 https://git.kernel.org/stable/c/9f329d0d6c91142cf0ad08d23c72dd195db2633c https://git.kernel.org/stable/c/e79ff8c68acb1eddf709d3ac84716868f • CWE-665: Improper Initialization •
CVSS: 5.5EPSS: 0%CPEs: 6EXPL: 0CVE-2021-46929 – sctp: use call_rcu to free endpoint
https://notcve.org/view.php?id=CVE-2021-46929
In the Linux kernel, the following vulnerability has been resolved: sctp: use call_rcu to free endpoint This patch is to delay the endpoint free by calling call_rcu() to fix another use-after-free issue in sctp_sock_dump(): BUG: KASAN: use-after-free in __lock_acquire+0x36d9/0x4c20 Call Trace: __lock_acquire+0x36d9/0x4c20 kernel/locking/lockdep.c:3218 lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168 spin_lock_bh include/linux/spinlock.h:334 [inline] __lock_sock+0x203/0x350 net/core/sock.c:2253 lock_sock_nested+0xfe/0x120 net/core/sock.c:2774 lock_sock include/net/sock.h:1492 [inline] sctp_sock_dump+0x122/0xb20 net/sctp/diag.c:324 sctp_for_each_transport+0x2b5/0x370 net/sctp/socket.c:5091 sctp_diag_dump+0x3ac/0x660 net/sctp/diag.c:527 __inet_diag_dump+0xa8/0x140 net/ipv4/inet_diag.c:1049 inet_diag_dump+0x9b/0x110 net/ipv4/inet_diag.c:1065 netlink_dump+0x606/0x1080 net/netlink/af_netlink.c:2244 __netlink_dump_start+0x59a/0x7c0 net/netlink/af_netlink.c:2352 netlink_dump_start include/linux/netlink.h:216 [inline] inet_diag_handler_cmd+0x2ce/0x3f0 net/ipv4/inet_diag.c:1170 __sock_diag_cmd net/core/sock_diag.c:232 [inline] sock_diag_rcv_msg+0x31d/0x410 net/core/sock_diag.c:263 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2477 sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:274 This issue occurs when asoc is peeled off and the old sk is freed after getting it by asoc->base.sk and before calling lock_sock(sk). To prevent the sk free, as a holder of the sk, ep should be alive when calling lock_sock(). This patch uses call_rcu() and moves sock_put and ep free into sctp_endpoint_destroy_rcu(), so that it's safe to try to hold the ep under rcu_read_lock in sctp_transport_traverse_process(). If sctp_endpoint_hold() returns true, it means this ep is still alive and we have held it and can continue to dump it; If it returns false, it means this ep is dead and can be freed after rcu_read_unlock, and we should skip it. In sctp_sock_dump(), after locking the sk, if this ep is different from tsp->asoc->ep, it means during this dumping, this asoc was peeled off before calling lock_sock(), and the sk should be skipped; If this ep is the same with tsp->asoc->ep, it means no peeloff happens on this asoc, and due to lock_sock, no peeloff will happen either until release_sock. Note that delaying endpoint free won't delay the port release, as the port release happens in sctp_endpoint_destroy() before calling call_rcu(). Also, freeing endpoint by call_rcu() makes it safe to access the sk by asoc->base.sk in sctp_assocs_seq_show() and sctp_rcv(). Thanks Jones to bring this issue up. v1->v2: - improve the changelog. - add kfree(ep) into sctp_endpoint_destroy_rcu(), as Jakub noticed. En el kernel de Linux, se resolvió la siguiente vulnerabilidad: sctp: use call_rcu para liberar el endpoint. Este parche tiene como objetivo retrasar la liberación del endpoint llamando a call_rcu() para solucionar otro problema de use-after-free en sctp_sock_dump(): ERROR: KASAN: use-after-free en __lock_acquire+0x36d9/0x4c20 Rastreo de llamadas: __lock_acquire+0x36d9/0x4c20 kernel/locking/lockdep.c:3218 lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844 __raw_spin_lock_bh include/linux/spinlock_api_smp.h :135 [en línea] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168 spin_lock_bh include/linux/spinlock.h:334 [en línea] __lock_sock+0x203/0x350 net/core/sock.c:2253 lock_sock_nested+0xfe/ 0x120 net/core/sock.c:2774 lock_sock include/net/sock.h:1492 [en línea] sctp_sock_dump+0x122/0xb20 net/sctp/diag.c:324 sctp_for_each_transport+0x2b5/0x370 net/sctp/socket.c: 5091 sctp_diag_dump+0x3ac/0x660 net/sctp/diag.c:527 __inet_diag_dump+0xa8/0x140 net/ipv4/inet_diag.c:1049 inet_diag_dump+0x9b/0x110 net/ipv4/inet_diag.c:1065 netlink_dump+0x6 06/0x1080 neto/ netlink/af_netlink.c:2244 __netlink_dump_start+0x59a/0x7c0 net/netlink/af_netlink.c:2352 netlink_dump_start include/linux/netlink.h:216 [en línea] inet_diag_handler_cmd+0x2ce/0x3f0 net/ipv4/inet_diag.c:1170 __sock_diag_cm re neto /core/sock_diag.c:232 [en línea] sock_diag_rcv_msg+0x31d/0x410 net/core/sock_diag.c:263 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2477 sock_diag_rcv+0x2a/0x40 net/core/sock_diag. c:274 Este problema ocurre cuando se quita asoc y se libera el sk antiguo después de obtenerlo mediante asoc->base.sk y antes de llamar a lock_sock(sk). Para evitar que sk se libere, como titular de sk, ep debe estar activo al llamar a lock_sock(). • https://git.kernel.org/stable/c/d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab https://git.kernel.org/stable/c/8873140f95d4977bf37e4cf0d5c5e3f6e34cdd3e https://git.kernel.org/stable/c/af6e6e58f7ebf86b4e7201694b1e4f3a62cbc3ec https://git.kernel.org/stable/c/831de271452b87657fcf8d715ee20519b79caef5 https://git.kernel.org/stable/c/769d14abd35e0e153b5149c3e1e989a9d719e3ff https://git.kernel.org/stable/c/75799e71df1da11394740b43ae5686646179561d https://git.kernel.org/stable/c/5ec7d18d1813a5bead0b495045606c93873aecbb • CWE-416: Use After Free •
CVSS: 5.5EPSS: 0%CPEs: 3EXPL: 0CVE-2021-46928 – parisc: Clear stale IIR value on instruction access rights trap
https://notcve.org/view.php?id=CVE-2021-46928
In the Linux kernel, the following vulnerability has been resolved: parisc: Clear stale IIR value on instruction access rights trap When a trap 7 (Instruction access rights) occurs, this means the CPU couldn't execute an instruction due to missing execute permissions on the memory region. In this case it seems the CPU didn't even fetched the instruction from memory and thus did not store it in the cr19 (IIR) register before calling the trap handler. So, the trap handler will find some random old stale value in cr19. This patch simply overwrites the stale IIR value with a constant magic "bad food" value (0xbaadf00d), in the hope people don't start to try to understand the various random IIR values in trap 7 dumps. En el kernel de Linux, se resolvió la siguiente vulnerabilidad: parisc: borra el valor IIR obsoleto en la trampa de derechos de acceso a instrucciones Cuando ocurre una trampa 7 (derechos de acceso a instrucciones), esto significa que la CPU no pudo ejecutar una instrucción debido a que faltan permisos de ejecución en la región de la memoria. En este caso, parece que la CPU ni siquiera obtuvo la instrucción de la memoria y, por lo tanto, no la almacenó en el registro cr19 (IIR) antes de llamar al controlador de trampas. • https://git.kernel.org/stable/c/d01e9ce1af6116f812491d3d3873d204f10ae0b8 https://git.kernel.org/stable/c/e96373f0a5f484bc1e193f9951dcb3adf24bf3f7 https://git.kernel.org/stable/c/484730e5862f6b872dca13840bed40fd7c60fa26 • CWE-755: Improper Handling of Exceptional Conditions •