diff options
Diffstat (limited to 'meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2024-26676.patch')
| -rw-r--r-- | meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2024-26676.patch | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2024-26676.patch b/meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2024-26676.patch new file mode 100644 index 000000000..2ff7af39d --- /dev/null +++ b/meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2024-26676.patch @@ -0,0 +1,107 @@ +From 1279f9d9dec2d7462823a18c29ad61359e0a007d Mon Sep 17 00:00:00 2001 +From: Kuniyuki Iwashima <kuniyu@amazon.com> +Date: Sat, 3 Feb 2024 10:31:49 -0800 +Subject: af_unix: Call kfree_skb() for dead unix_(sk)->oob_skb in GC. + +syzbot reported a warning [0] in __unix_gc() with a repro, which +creates a socketpair and sends one socket's fd to itself using the +peer. + + socketpair(AF_UNIX, SOCK_STREAM, 0, [3, 4]) = 0 + sendmsg(4, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="\360", iov_len=1}], + msg_iovlen=1, msg_control=[{cmsg_len=20, cmsg_level=SOL_SOCKET, + cmsg_type=SCM_RIGHTS, cmsg_data=[3]}], + msg_controllen=24, msg_flags=0}, MSG_OOB|MSG_PROBE|MSG_DONTWAIT|MSG_ZEROCOPY) = 1 + +This forms a self-cyclic reference that GC should finally untangle +but does not due to lack of MSG_OOB handling, resulting in memory +leak. + +Recently, commit 11498715f266 ("af_unix: Remove io_uring code for +GC.") removed io_uring's dead code in GC and revealed the problem. + +The code was executed at the final stage of GC and unconditionally +moved all GC candidates from gc_candidates to gc_inflight_list. +That papered over the reported problem by always making the following +WARN_ON_ONCE(!list_empty(&gc_candidates)) false. + +The problem has been there since commit 2aab4b969002 ("af_unix: fix +struct pid leaks in OOB support") added full scm support for MSG_OOB +while fixing another bug. + +To fix this problem, we must call kfree_skb() for unix_sk(sk)->oob_skb +if the socket still exists in gc_candidates after purging collected skb. + +Then, we need to set NULL to oob_skb before calling kfree_skb() because +it calls last fput() and triggers unix_release_sock(), where we call +duplicate kfree_skb(u->oob_skb) if not NULL. + +Note that the leaked socket remained being linked to a global list, so +kmemleak also could not detect it. We need to check /proc/net/protocol +to notice the unfreed socket. + +[0]: +WARNING: CPU: 0 PID: 2863 at net/unix/garbage.c:345 __unix_gc+0xc74/0xe80 net/unix/garbage.c:345 +Modules linked in: +CPU: 0 PID: 2863 Comm: kworker/u4:11 Not tainted 6.8.0-rc1-syzkaller-00583-g1701940b1a02 #0 +Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 +Workqueue: events_unbound __unix_gc +RIP: 0010:__unix_gc+0xc74/0xe80 net/unix/garbage.c:345 +Code: 8b 5c 24 50 e9 86 f8 ff ff e8 f8 e4 22 f8 31 d2 48 c7 c6 30 6a 69 89 4c 89 ef e8 97 ef ff ff e9 80 f9 ff ff e8 dd e4 22 f8 90 <0f> 0b 90 e9 7b fd ff ff 48 89 df e8 5c e7 7c f8 e9 d3 f8 ff ff e8 +RSP: 0018:ffffc9000b03fba0 EFLAGS: 00010293 +RAX: 0000000000000000 RBX: ffffc9000b03fc10 RCX: ffffffff816c493e +RDX: ffff88802c02d940 RSI: ffffffff896982f3 RDI: ffffc9000b03fb30 +RBP: ffffc9000b03fce0 R08: 0000000000000001 R09: fffff52001607f66 +R10: 0000000000000003 R11: 0000000000000002 R12: dffffc0000000000 +R13: ffffc9000b03fc10 R14: ffffc9000b03fc10 R15: 0000000000000001 +FS: 0000000000000000(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 +CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 +CR2: 00005559c8677a60 CR3: 000000000d57a000 CR4: 00000000003506f0 +DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 +DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 +Call Trace: + <TASK> + process_one_work+0x889/0x15e0 kernel/workqueue.c:2633 + process_scheduled_works kernel/workqueue.c:2706 [inline] + worker_thread+0x8b9/0x12a0 kernel/workqueue.c:2787 + kthread+0x2c6/0x3b0 kernel/kthread.c:388 + ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 + ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242 + </TASK> + +Reported-by: syzbot+fa3ef895554bdbfd1183@syzkaller.appspotmail.com +Closes: https://syzkaller.appspot.com/bug?extid=fa3ef895554bdbfd1183 +Fixes: 2aab4b969002 ("af_unix: fix struct pid leaks in OOB support") +Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> +Reviewed-by: Eric Dumazet <edumazet@google.com> +Link: https://lore.kernel.org/r/20240203183149.63573-1-kuniyu@amazon.com +Signed-off-by: Jakub Kicinski <kuba@kernel.org> +--- + net/unix/garbage.c | 11 +++++++++++ + 1 file changed, 11 insertions(+) + +diff --git a/net/unix/garbage.c b/net/unix/garbage.c +index 2405f0f9af31c0..8f63f0b4bf0129 100644 +--- a/net/unix/garbage.c ++++ b/net/unix/garbage.c +@@ -314,6 +314,17 @@ void unix_gc(void) + /* Here we are. Hitlist is filled. Die. */ + __skb_queue_purge(&hitlist); + ++#if IS_ENABLED(CONFIG_AF_UNIX_OOB) ++ list_for_each_entry_safe(u, next, &gc_candidates, link) { ++ struct sk_buff *skb = u->oob_skb; ++ ++ if (skb) { ++ u->oob_skb = NULL; ++ kfree_skb(skb); ++ } ++ } ++#endif ++ + spin_lock(&unix_gc_lock); + + /* All candidates should have been detached by now. */ +-- +cgit 1.2.3-korg + |