Heimdall Security Logo

CVE-2021-47238

Vulnérabilité moyenne dans Linux (Linux)

CVSS 5.5 · Moyenne
EPSS 0.2%
Linux•Linux•Versions : 5.4.128, 0, <ac31cc837cafb57a271babad8ccffbf733caa076, <3.3, <=4.9.*, <1e28018b5c83d5073f74a6fb72eabe8370b2f501, <6cff57eea3347f79f1867cc53e1093b6614138d8, <=4.14.*, <=5.10.*, 5.12.13, 4.14.238, <0dc13e75507faa17ac9f7562b4ef7bf8fcd78422, <3dd2aeac2e9624cff9fa634710837e4f2e352758, <=5.4.*, 5.13, <4.9, <=4.19.*, <=5.12.*, <d8e2973029b8b2ce477b564824431f3385c77083, 4.9.274, 3.2.87, bd1b664a19403ede448d29c87b2f23796bc7a577, <77de6ee73f54a9a89c0afa0bf4c53b239aa9953a, 4.19.196, <=*, 4.9, 5.10.46, b38c6e0bd5b5e439ecebdc0df599d573c2f610f8, 3.16.42, 24803f38a5c0b6c57ed800b47e695f9ce474bc3a, <3.17

Description

In the Linux kernel, the following vulnerability has been resolved: net: ipv4: fix memory leak in ip_mc_add1_src BUG: memory leak unreferenced object 0xffff888101bc4c00 (size 32): comm "syz-executor527", pid 360, jiffies 4294807421 (age 19.329s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 01 00 00 00 00 00 00 00 ac 14 14 bb 00 00 02 00 ................ backtrace: [<00000000f17c5244>] kmalloc include/linux/slab.h:558 [inline] [<00000000f17c5244>] kzalloc include/linux/slab.h:688 [inline] [<00000000f17c5244>] ip_mc_add1_src net/ipv4/igmp.c:1971 [inline] [<00000000f17c5244>] ip_mc_add_src+0x95f/0xdb0 net/ipv4/igmp.c:2095 [<000000001cb99709>] ip_mc_source+0x84c/0xea0 net/ipv4/igmp.c:2416 [<0000000052cf19ed>] do_ip_setsockopt net/ipv4/ip_sockglue.c:1294 [inline] [<0000000052cf19ed>] ip_setsockopt+0x114b/0x30c0 net/ipv4/ip_sockglue.c:1423 [<00000000477edfbc>] raw_setsockopt+0x13d/0x170 net/ipv4/raw.c:857 [<00000000e75ca9bb>] __sys_setsockopt+0x158/0x270 net/socket.c:2117 [<00000000bdb993a8>] __do_sys_setsockopt net/socket.c:2128 [inline] [<00000000bdb993a8>] __se_sys_setsockopt net/socket.c:2125 [inline] [<00000000bdb993a8>] __x64_sys_setsockopt+0xba/0x150 net/socket.c:2125 [<000000006a1ffdbd>] do_syscall_64+0x40/0x80 arch/x86/entry/common.c:47 [<00000000b11467c4>] entry_SYSCALL_64_after_hwframe+0x44/0xae In commit 24803f38a5c0 ("igmp: do not remove igmp souce list info when set link down"), the ip_mc_clear_src() in ip_mc_destroy_dev() was removed, because it was also called in igmpv3_clear_delrec(). Rough callgraph: inetdev_destroy -> ip_mc_destroy_dev -> igmpv3_clear_delrec -> ip_mc_clear_src -> RCU_INIT_POINTER(dev->ip_ptr, NULL) However, ip_mc_clear_src() called in igmpv3_clear_delrec() doesn't release in_dev->mc_list->sources. And RCU_INIT_POINTER() assigns the NULL to dev->ip_ptr. As a result, in_dev cannot be obtained through inetdev_by_index() and then in_dev->mc_list->sources cannot be released by ip_mc_del1_src() in the sock_close. Rough call sequence goes like: sock_close -> __sock_release -> inet_release -> ip_mc_drop_socket -> inetdev_by_index -> ip_mc_leave_src -> ip_mc_del_src -> ip_mc_del1_src So we still need to call ip_mc_clear_src() in ip_mc_destroy_dev() to free in_dev->mc_list->sources.

Gravité et risque d'exploitation

CVE-2021-47238 obtient un score CVSS de 5.5/10, soit une gravité moyenne. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.24 %, ce qui la place devant 13.7 % des CVE référencées.

Que faire ?

  • Vérifiez si Linux (versions 5.4.128, 0, <ac31cc837cafb57a271babad8ccffbf733caa076, <3.3, <=4.9.*, <1e28018b5c83d5073f74a6fb72eabe8370b2f501, <6cff57eea3347f79f1867cc53e1093b6614138d8, <=4.14.*, <=5.10.*, 5.12.13, 4.14.238, <0dc13e75507faa17ac9f7562b4ef7bf8fcd78422, <3dd2aeac2e9624cff9fa634710837e4f2e352758, <=5.4.*, 5.13, <4.9, <=4.19.*, <=5.12.*, <d8e2973029b8b2ce477b564824431f3385c77083, 4.9.274, 3.2.87, bd1b664a19403ede448d29c87b2f23796bc7a577, <77de6ee73f54a9a89c0afa0bf4c53b239aa9953a, 4.19.196, <=*, 4.9, 5.10.46, b38c6e0bd5b5e439ecebdc0df599d573c2f610f8, 3.16.42, 24803f38a5c0b6c57ed800b47e695f9ce474bc3a, <3.17) est présent sur votre parc.
  • Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
  • À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
  • Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

Rechercher une autre CVE