Bugzilla – Bug 1224845
VUL-0: CVE-2021-47243: kernel: sch_cake: Fix out of bounds when parsing TCP options and header
Last modified: 2024-07-19 18:05:38 UTC
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. References: http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2021-47243 https://www.cve.org/CVERecord?id=CVE-2021-47243 https://git.kernel.org/stable/c/3371392c60e2685af30bd4547badd880f5df2b3f https://git.kernel.org/stable/c/3b491dd593d582ceeb27aa617600712a6bd14246 https://git.kernel.org/stable/c/4cefa061fc63f4d2dff5ab4083f43857cd7a2335 https://git.kernel.org/stable/c/595897ef118d6fe66690c4fc5b572028c9da95b7 https://git.kernel.org/stable/c/ba91c49dedbde758ba0b72f57ac90b06ddf8e548 https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2021/CVE-2021-47243.mbox
nothing to be done