Bug 2048934 (CVE-2021-45952) - CVE-2021-45952 dnsmasq: a heap-based buffer overflow in dhcp_reply
Summary: CVE-2021-45952 dnsmasq: a heap-based buffer overflow in dhcp_reply
Keywords:
Status: CLOSED NOTABUG
Alias: CVE-2021-45952
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2048935
Blocks: 2048923
TreeView+ depends on / blocked
 
Reported: 2022-02-01 08:30 UTC by Marian Rehak
Modified: 2023-03-14 10:19 UTC (History)
16 users (show)

Fixed In Version:
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Last Closed: 2022-05-24 23:42:39 UTC
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Description Marian Rehak 2022-02-01 08:30:48 UTC 
A heap-based buffer overflow in dhcp_reply (called from dhcp_packet and FuzzDhcp).

Reference:

https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=35870
https://github.com/google/oss-fuzz-vulns/blob/main/vulns/dnsmasq/OSV-2021-927.yaml
Comment 1 Marian Rehak 2022-02-01 08:31:05 UTC 
Created dnsmasq tracking bugs for this issue:

Affects: fedora-all [bug 2048935]
Comment 5 Petr Menšík 2022-02-17 02:33:34 UTC 
It seems this is again bogus report. void dhcp_common_init(void) always initializes daemon->dhcp_packet to sizeof(struct dhcp_packet) size. But fuzzers allocates only fixed 300 bytes, which is not enough. clear_packet() clears whole buffer regardless how large incoming packet was. It requires full buffer therefore.
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