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Bug 711126 (CVE-2020-9391) - kernel: brk discards top byte of addresses on aarch64, causing heap corruption in glibc malloc (CVE-2020-9391)
Summary: kernel: brk discards top byte of addresses on aarch64, causing heap corruptio...
Status: RESOLVED UPSTREAM
Alias: CVE-2020-9391
Product: Gentoo Security
Classification: Unclassified
Component: Kernel (show other bugs)
Hardware: ARM64 Linux
: Normal trivial (vote)
Assignee: Gentoo Kernel Security
URL: https://www.openwall.com/lists/oss-se...
Whiteboard: ~3 [upstream/ebuild]
Keywords:
Depends on:
Blocks:
 
Reported: 2020-03-01 01:20 UTC by Sam James
Modified: 2020-03-02 21:55 UTC (History)
0 users

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Description Sam James archtester Gentoo Infrastructure gentoo-dev Security 2020-03-01 01:20:46 UTC 
"An issue was discovered in the Linux kernel 5.4 and 5.5 through 5.5.6 on the AArch64 architecture. It ignores the top byte in the address passed to the brk system call, potentially moving the memory break downwards when the application expects it to move upwards, aka CID-dcde237319e6. This has been observed to cause heap corruption with the GNU C Library malloc implementation."

Affects: aarch64/arm64

Patch: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dcde237319e626d1ec3c9d8b7613032f0fd4663a
Comment 1 Thomas Deutschmann (RETIRED) gentoo-dev 2020-03-02 21:53:07 UTC 
Only affecting 5.4+
Comment 2 Thomas Deutschmann (RETIRED) gentoo-dev 2020-03-02 21:55:24 UTC 
We don't stabilize kernel sources for aarch64.