Bug 2363691 (CVE-2023-53121)

Summary: CVE-2023-53121 kernel: tcp: tcp_make_synack() can be called from process context
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description OSIDB Bzimport 2025-05-02 16:01:53 UTC
In the Linux kernel, the following vulnerability has been resolved:

tcp: tcp_make_synack() can be called from process context

tcp_rtx_synack() now could be called in process context as explained in
0a375c822497 ("tcp: tcp_rtx_synack() can be called from process
context").

tcp_rtx_synack() might call tcp_make_synack(), which will touch per-CPU
variables with preemption enabled. This causes the following BUG:

    BUG: using __this_cpu_add() in preemptible [00000000] code: ThriftIO1/5464
    caller is tcp_make_synack+0x841/0xac0
    Call Trace:
     <TASK>
     dump_stack_lvl+0x10d/0x1a0
     check_preemption_disabled+0x104/0x110
     tcp_make_synack+0x841/0xac0
     tcp_v6_send_synack+0x5c/0x450
     tcp_rtx_synack+0xeb/0x1f0
     inet_rtx_syn_ack+0x34/0x60
     tcp_check_req+0x3af/0x9e0
     tcp_rcv_state_process+0x59b/0x2030
     tcp_v6_do_rcv+0x5f5/0x700
     release_sock+0x3a/0xf0
     tcp_sendmsg+0x33/0x40
     ____sys_sendmsg+0x2f2/0x490
     __sys_sendmsg+0x184/0x230
     do_syscall_64+0x3d/0x90

Avoid calling __TCP_INC_STATS() with will touch per-cpu variables. Use
TCP_INC_STATS() which is safe to be called from context switch.

Comment 1 Avinash Hanwate 2025-05-05 06:54:06 UTC
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025050231-CVE-2023-53121-40ec@gregkh/T