7.1
CWE
125
Advisory Published
Updated

CVE-2021-47243: sch_cake: Fix out of bounds when parsing TCP options and header

First published: Tue May 21 2024(Updated: )

In the Linux kernel, the following vulnerability has been resolved: sch_cake: Fix out of bounds when parsing TCP options and header The TCP option parser in cake qdisc (cake_get_tcpopt and cake_tcph_may_drop) could read one byte out of bounds. When the length is 1, the execution flow gets into the loop, reads one byte of the opcode, and if the opcode is neither TCPOPT_EOL nor TCPOPT_NOP, it reads one more byte, which exceeds the length of 1. This fix is inspired by commit 9609dad263f8 ("ipv4: tcp_input: fix stack out of bounds when parsing TCP options."). v2 changes: Added doff validation in cake_get_tcphdr to avoid parsing garbage as TCP header. Although it wasn't strictly an out-of-bounds access (memory was allocated), garbage values could be read where CAKE expected the TCP header if doff was smaller than 5.

Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Affected SoftwareAffected VersionHow to fix
Linux Linux kernel>=4.19<4.19.196
Linux Linux kernel>=4.20<5.4.128
Linux Linux kernel>=5.5<5.10.46
Linux Linux kernel>=5.11<5.12.13
Linux Linux kernel=5.13-rc1
Linux Linux kernel=5.13-rc2
Linux Linux kernel=5.13-rc3
Linux Linux kernel=5.13-rc4
Linux Linux kernel=5.13-rc5
Linux Linux kernel=5.13-rc6

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