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Infinite loop due to integer overflow #210

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wengyusu opened this issue Nov 18, 2020 · 1 comment
Closed

Infinite loop due to integer overflow #210

wengyusu opened this issue Nov 18, 2020 · 1 comment

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@wengyusu
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#207

net-snmp/agent/mibgroup/util_funcs/header_simple_table.c

Line 97 in 7c3723c

if ((max >= 0 && ((int)newname[*length - 1] > max)) ||

when operating GETNEXT to the OID 1.3.6.1.4.1.2021.9.1.1.4294967295, the (int)newname[*length - 1] becomes -1 since newname[*length - 1]=4294967295(0XFFFFFFFF) that breaks the comparison and causes an infinite loop. As a result, the SNMPD will stuck, and CPU usage reaches 100%.
bvanassche added a commit that referenced this issue Nov 19, 2020
@bvanassche
CHANGES: snmpd: Fix OID handling in header_simple_table()
ebe677e 
Process GETNEXT for OIDs like 1.3.6.1.4.1.2021.9.1.1.4294967295 correctly.
Additionally, handle *length == 0 correctly.

See also #210 .
@bvanassche
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Please take a look at commit ebe677e.

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@bvanassche @wengyusu