CVE-2021-46947
SFC Kernel NULL Pointer Dereference
Description
In the Linux kernel, the following vulnerability has been resolved: sfc: adjust efx->xdp_tx_queue_count with the real number of initialized queues efx->xdp_tx_queue_count is initially initialized to num_possible_cpus() and is later used to allocate and traverse efx->xdp_tx_queues lookup array. However, we may end up not initializing all the array slots with real queues during probing. This results, for example, in a NULL pointer dereference, when running "# ethtool -S <iface>", similar to below [2570283.664955][T4126959] BUG: kernel NULL pointer dereference, address: 00000000000000f8 [2570283.681283][T4126959] #PF: supervisor read access in kernel mode [2570283.695678][T4126959] #PF: error_code(0x0000) - not-present page [2570283.710013][T4126959] PGD 0 P4D 0 [2570283.721649][T4126959] Oops: 0000 [#1] SMP PTI [2570283.734108][T4126959] CPU: 23 PID: 4126959 Comm: ethtool Tainted: G O 5.10.20-cloudflare-2021.3.1 #1 [2570283.752641][T4126959] Hardware name: <redacted> [2570283.781408][T4126959] RIP: 0010:efx_ethtool_get_stats+0x2ca/0x330 [sfc] [2570283.796073][T4126959] Code: 00 85 c0 74 39 48 8b 95 a8 0f 00 00 48 85 d2 74 2d 31 c0 eb 07 48 8b 95 a8 0f 00 00 48 63 c8 49 83 c4 08 83 c0 01 48 8b 14 ca <48> 8b 92 f8 00 00 00 49 89 54 24 f8 39 85 a0 0f 00 00 77 d7 48 8b [2570283.831259][T4126959] RSP: 0018:ffffb79a77657ce8 EFLAGS: 00010202 [2570283.845121][T4126959] RAX: 0000000000000019 RBX: ffffb799cd0c9280 RCX: 0000000000000018 [2570283.860872][T4126959] RDX: 0000000000000000 RSI: ffff96dd970ce000 RDI: 0000000000000005 [2570283.876525][T4126959] RBP: ffff96dd86f0a000 R08: ffff96dd970ce480 R09: 000000000000005f [2570283.892014][T4126959] R10: ffffb799cd0c9fff R11: ffffb799cd0c9000 R12: ffffb799cd0c94f8 [2570283.907406][T4126959] R13: ffffffffc11b1090 R14: ffff96dd970ce000 R15: ffffffffc11cd66c [2570283.922705][T4126959] FS: 00007fa7723f8740(0000) GS:ffff96f51fac0000(0000) knlGS:0000000000000000 [2570283.938848][T4126959] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [2570283.952524][T4126959] CR2: 00000000000000f8 CR3: 0000001a73e6e006 CR4: 00000000007706e0 [2570283.967529][T4126959] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [2570283.982400][T4126959] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [2570283.997308][T4126959] PKRU: 55555554 [2570284.007649][T4126959] Call Trace: [2570284.017598][T4126959] dev_ethtool+0x1832/0x2830 Fix this by adjusting efx->xdp_tx_queue_count after probing to reflect the true value of initialized slots in efx->xdp_tx_queues.
INFO
Published Date :
Feb. 27, 2024, 7:04 p.m.
Last Modified :
April 10, 2024, 8 p.m.
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Remotely Exploitable :
No
Impact Score :
3.6
Exploitability Score :
1.8
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2021-46947.
| URL | Resource |
|---|---|
| https://git.kernel.org/stable/c/99ba0ea616aabdc8e26259fd722503e012199a76 | Patch |
| https://git.kernel.org/stable/c/ebeac958b690123a0b40aa61f688f2f170035fad | Patch |
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2021-46947 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2021-46947 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 28, 2024
Action Type Old Value New Value -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 14, 2024
Action Type Old Value New Value -
Initial Analysis by [email protected]
Apr. 10, 2024
Action Type Old Value New Value Added CVSS V3.1 NIST AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Changed Reference Type https://git.kernel.org/stable/c/99ba0ea616aabdc8e26259fd722503e012199a76 No Types Assigned https://git.kernel.org/stable/c/99ba0ea616aabdc8e26259fd722503e012199a76 Patch Changed Reference Type https://git.kernel.org/stable/c/ebeac958b690123a0b40aa61f688f2f170035fad No Types Assigned https://git.kernel.org/stable/c/ebeac958b690123a0b40aa61f688f2f170035fad Patch Added CWE NIST CWE-476 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.12.0 up to (excluding) 5.12.3 -
CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Feb. 27, 2024
Action Type Old Value New Value Added Description In the Linux kernel, the following vulnerability has been resolved: sfc: adjust efx->xdp_tx_queue_count with the real number of initialized queues efx->xdp_tx_queue_count is initially initialized to num_possible_cpus() and is later used to allocate and traverse efx->xdp_tx_queues lookup array. However, we may end up not initializing all the array slots with real queues during probing. This results, for example, in a NULL pointer dereference, when running "# ethtool -S <iface>", similar to below [2570283.664955][T4126959] BUG: kernel NULL pointer dereference, address: 00000000000000f8 [2570283.681283][T4126959] #PF: supervisor read access in kernel mode [2570283.695678][T4126959] #PF: error_code(0x0000) - not-present page [2570283.710013][T4126959] PGD 0 P4D 0 [2570283.721649][T4126959] Oops: 0000 [#1] SMP PTI [2570283.734108][T4126959] CPU: 23 PID: 4126959 Comm: ethtool Tainted: G O 5.10.20-cloudflare-2021.3.1 #1 [2570283.752641][T4126959] Hardware name: <redacted> [2570283.781408][T4126959] RIP: 0010:efx_ethtool_get_stats+0x2ca/0x330 [sfc] [2570283.796073][T4126959] Code: 00 85 c0 74 39 48 8b 95 a8 0f 00 00 48 85 d2 74 2d 31 c0 eb 07 48 8b 95 a8 0f 00 00 48 63 c8 49 83 c4 08 83 c0 01 48 8b 14 ca <48> 8b 92 f8 00 00 00 49 89 54 24 f8 39 85 a0 0f 00 00 77 d7 48 8b [2570283.831259][T4126959] RSP: 0018:ffffb79a77657ce8 EFLAGS: 00010202 [2570283.845121][T4126959] RAX: 0000000000000019 RBX: ffffb799cd0c9280 RCX: 0000000000000018 [2570283.860872][T4126959] RDX: 0000000000000000 RSI: ffff96dd970ce000 RDI: 0000000000000005 [2570283.876525][T4126959] RBP: ffff96dd86f0a000 R08: ffff96dd970ce480 R09: 000000000000005f [2570283.892014][T4126959] R10: ffffb799cd0c9fff R11: ffffb799cd0c9000 R12: ffffb799cd0c94f8 [2570283.907406][T4126959] R13: ffffffffc11b1090 R14: ffff96dd970ce000 R15: ffffffffc11cd66c [2570283.922705][T4126959] FS: 00007fa7723f8740(0000) GS:ffff96f51fac0000(0000) knlGS:0000000000000000 [2570283.938848][T4126959] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [2570283.952524][T4126959] CR2: 00000000000000f8 CR3: 0000001a73e6e006 CR4: 00000000007706e0 [2570283.967529][T4126959] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [2570283.982400][T4126959] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [2570283.997308][T4126959] PKRU: 55555554 [2570284.007649][T4126959] Call Trace: [2570284.017598][T4126959] dev_ethtool+0x1832/0x2830 Fix this by adjusting efx->xdp_tx_queue_count after probing to reflect the true value of initialized slots in efx->xdp_tx_queues. Added Reference Linux https://git.kernel.org/stable/c/ebeac958b690123a0b40aa61f688f2f170035fad [No types assigned] Added Reference Linux https://git.kernel.org/stable/c/99ba0ea616aabdc8e26259fd722503e012199a76 [No types assigned]
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2021-46947 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2021-46947
weaknesses.