Bug 2348342 (CVE-2022-49307)

Summary: CVE-2022-49307 kernel: tty: synclink_gt: Fix null-pointer-dereference in slgt_clean()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-02-26 03:26:07 UTC 
In the Linux kernel, the following vulnerability has been resolved:

tty: synclink_gt: Fix null-pointer-dereference in slgt_clean()

When the driver fails at alloc_hdlcdev(), and then we remove the driver
module, we will get the following splat:

[   25.065966] general protection fault, probably for non-canonical address 0xdffffc0000000182: 0000 [#1] PREEMPT SMP KASAN PTI
[   25.066914] KASAN: null-ptr-deref in range [0x0000000000000c10-0x0000000000000c17]
[   25.069262] RIP: 0010:detach_hdlc_protocol+0x2a/0x3e0
[   25.077709] Call Trace:
[   25.077924]  <TASK>
[   25.078108]  unregister_hdlc_device+0x16/0x30
[   25.078481]  slgt_cleanup+0x157/0x9f0 [synclink_gt]

Fix this by checking whether the 'info->netdev' is a null pointer first.
Comment 1 Avinash Hanwate 2025-02-26 07:48:53 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022635-CVE-2022-49307-246e@gregkh/T
Comment 4 Avinash Hanwate 2025-02-26 09:24:45 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025022635-CVE-2022-49307-246e@gregkh/T