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ipc, msg: Use dedicated slab buckets for alloc_msg()

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The msg subsystem is a common target for exploiting[1][2][3][4][5][6][7]
use-after-free type confusion flaws in the kernel for both read and write
primitives. Avoid having a user-controlled dynamically-size allocation
share the global kmalloc cache by using a separate set of kmalloc buckets
via the kmem_buckets API.

Link: https://blog.hacktivesecurity.com/index.php/2022/06/13/linux-kernel-exploit-development-1day-case-study/ [1]
Link: https://hardenedvault.net/blog/2022-11-13-msg_msg-recon-mitigation-ved/ [2]
Link: https://www.willsroot.io/2021/08/corctf-2021-fire-of-salvation-writeup.html [3]
Link: https://a13xp0p0v.github.io/2021/02/09/CVE-2021-26708.html [4]
Link: https://google.github.io/security-research/pocs/linux/cve-2021-22555/writeup.html [5]
Link: https://zplin.me/papers/ELOISE.pdf [6]
Link: https://syst3mfailure.io/wall-of-perdition/ [7]
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
This commit is contained in:
Kees Cook 2024-07-01 12:13:02 -07:00 committed by Vlastimil Babka
parent b32801d125
commit 734bbc1c97
1 changed files with 12 additions and 1 deletions
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13
ipc/msgutil.c
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@ -42,6 +42,17 @@ struct msg_msgseg {
#define DATALEN_MSG ((size_t)PAGE_SIZE-sizeof(struct msg_msg)) #define DATALEN_MSG ((size_t)PAGE_SIZE-sizeof(struct msg_msg))
#define DATALEN_SEG ((size_t)PAGE_SIZE-sizeof(struct msg_msgseg)) #define DATALEN_SEG ((size_t)PAGE_SIZE-sizeof(struct msg_msgseg))
static kmem_buckets *msg_buckets __ro_after_init;
static int __init init_msg_buckets(void)
{
msg_buckets = kmem_buckets_create("msg_msg", SLAB_ACCOUNT,
sizeof(struct msg_msg),
DATALEN_MSG, NULL);
return 0;
}
subsys_initcall(init_msg_buckets);
static struct msg_msg *alloc_msg(size_t len) static struct msg_msg *alloc_msg(size_t len)
{ {
@ -50,7 +61,7 @@ static struct msg_msg *alloc_msg(size_t len)
size_t alen; size_t alen;
alen = min(len, DATALEN_MSG); alen = min(len, DATALEN_MSG);
msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL_ACCOUNT); msg = kmem_buckets_alloc(msg_buckets, sizeof(*msg) + alen, GFP_KERNEL);
if (msg == NULL) if (msg == NULL)
return NULL; return NULL;