CVE-2021-47129
netfilter: nft_ct: skip expectations for confirmed conntrack
Severity Score
Exploit Likelihood
Affected Versions
Public Exploits
0Exploited in Wild
-Decision
Descriptions
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nft_ct: skip expectations for confirmed conntrack
nft_ct_expect_obj_eval() calls nf_ct_ext_add() for a confirmed
conntrack entry. However, nf_ct_ext_add() can only be called for
!nf_ct_is_confirmed().
[ 1825.349056] WARNING: CPU: 0 PID: 1279 at net/netfilter/nf_conntrack_extend.c:48 nf_ct_xt_add+0x18e/0x1a0 [nf_conntrack]
[ 1825.351391] RIP: 0010:nf_ct_ext_add+0x18e/0x1a0 [nf_conntrack]
[ 1825.351493] Code: 41 5c 41 5d 41 5e 41 5f c3 41 bc 0a 00 00 00 e9 15 ff ff ff ba 09 00 00 00 31 f6 4c 89 ff e8 69 6c 3d e9 eb 96 45 31 ed eb cd <0f> 0b e9 b1 fe ff ff e8 86 79 14 e9 eb bf 0f 1f 40 00 0f 1f 44 00
[ 1825.351721] RSP: 0018:ffffc90002e1f1e8 EFLAGS: 00010202
[ 1825.351790] RAX: 000000000000000e RBX: ffff88814f5783c0 RCX: ffffffffc0e4f887
[ 1825.351881] RDX: dffffc0000000000 RSI: 0000000000000008 RDI: ffff88814f578440
[ 1825.351971] RBP: 0000000000000000 R08: 0000000000000000 R09: ffff88814f578447
[ 1825.352060] R10: ffffed1029eaf088 R11: 0000000000000001 R12: ffff88814f578440
[ 1825.352150] R13: ffff8882053f3a00 R14: 0000000000000000 R15: 0000000000000a20
[ 1825.352240] FS: 00007f992261c900(0000) GS:ffff889faec00000(0000) knlGS:0000000000000000
[ 1825.352343] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1825.352417] CR2: 000056070a4d1158 CR3: 000000015efe0000 CR4: 0000000000350ee0
[ 1825.352508] Call Trace:
[ 1825.352544] nf_ct_helper_ext_add+0x10/0x60 [nf_conntrack]
[ 1825.352641] nft_ct_expect_obj_eval+0x1b8/0x1e0 [nft_ct]
[ 1825.352716] nft_do_chain+0x232/0x850 [nf_tables]
Add the ct helper extension only for unconfirmed conntrack. Skip rule
evaluation if the ct helper extension does not exist. Thus, you can
only create expectations from the first packet.
It should be possible to remove this limitation by adding a new action
to attach a generic ct helper to the first packet. Then, use this ct
helper extension from follow up packets to create the ct expectation.
While at it, add a missing check to skip the template conntrack too
and remove check for IPCT_UNTRACK which is implicit to !ct.
En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: netfilter: nft_ct: omitir expectativas para conntrack confirmado nft_ct_expect_obj_eval() llama a nf_ct_ext_add() para una entrada de conntrack confirmada. Sin embargo, nf_ct_ext_add() solo se puede invocar para !nf_ct_is_confirmed(). [1825.349056] ADVERTENCIA: CPU: 0 PID: 1279 en net/netfilter/nf_conntrack_extend.c:48 nf_ct_xt_add+0x18e/0x1a0 [nf_conntrack] [1825.351391] RIP: 0010:nf_ct_ext_add+0x18e/0x 1a0 [nf_conntrack] [ 1825.351493] Código: 41 5c 41 5d 41 5e 41 5f c3 41 bc 0a 00 00 00 e9 15 ff ff ff ba 09 00 00 00 31 f6 4c 89 ff e8 69 6c 3d e9 eb 96 45 31 ed eb cd <0f> 0b e9 b1 fe ff ff e8 86 79 14 e9 eb bf 0f 1f 40 00 0f 1f 44 00 [ 1825.351721] RSP: 0018:ffffc90002e1f1e8 EFLAGS: 00010202 [ 1825.351790] RAX: 00000000000000 0e RBX: ffff88814f5783c0 RCX: ffffffffc0e4f887 [ 1825.351881] RDX: dffffc0000000000 RSI: 00000000000000008 RDI: ffff88814f578440 [ 1825.351971] RBP: 0000000000000000 R08: 0000000000000000 R09: ffff88814f578447 [ 1825.352060] R10: ffffed1029eaf088 R11: 00000000000000 01 R12: ffff88814f578440 [ 1825.352150] R13: ffff8882053f3a00 R14: 0000000000000000 R15: 0000000000000a20 [ 1825.352240] FS: 00007f99226 1c900(0000) GS:ffff889faec00000(0000 ) knlGS:0000000000000000 [ 1825.352343] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1825.352417] CR2: 000056070a4d1158 CR3: 00000001 5efe0000 CR4: 0000000000350ee0 [1825.352508] Seguimiento de llamadas: [1825.352544] nf_ct_helper_ext_add+0x10/0x60 [nf_conntrack] [1825.352641 ] nft_ct_expect_obj_eval+0x1b8/0x1e0 [nft_ct] [ 1825.352716] nft_do_chain+0x232/0x850 [nf_tables] Agregue la extensión ct helper solo para conntrack no confirmado. Omita la evaluación de la regla si la extensión ct helper no existe. Por lo tanto, sólo puedes crear expectativas desde el primer paquete. Debería ser posible eliminar esta limitación agregando una nueva acción para adjuntar un asistente ct genérico al primer paquete. Luego, use esta extensión de ayuda de ct de los paquetes de seguimiento para crear la expectativa de ct. Mientras lo hace, agregue una marca faltante para omitir también la plantilla conntrack y elimine la marca IPCT_UNTRACK que está implícita en !ct.
CVSS Scores
SSVC
- Decision:Track
Timeline
- 2024-03-04 CVE Reserved
- 2024-03-15 CVE Published
- 2024-03-16 EPSS Updated
- 2024-12-19 CVE Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
- CWE-273: Improper Check for Dropped Privileges
CAPEC
References (5)
| URL | Tag | Source |
|---|---|---|
| https://git.kernel.org/stable/c/857b46027d6f91150797295752581b7155b9d0e1 | Vuln. Introduced |
| URL | Date | SRC |
|---|
| URL | Date | SRC |
|---|
Affected Vendors, Products, and Versions
| Vendor | Product | Version | Other | Status | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Vendor | Product | Version | Other | Status | <-- --> | Vendor | Product | Version | Other | Status |
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.3 < 5.4.125 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.3 < 5.4.125" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.3 < 5.10.43 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.3 < 5.10.43" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.3 < 5.12.10 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.3 < 5.12.10" | en |
Affected
| ||||||
| Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.3 < 5.13 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.3 < 5.13" | en |
Affected
| ||||||