Grub2: ufs: integer overflow may lead to heap based out-of-bounds write when handling symlinks

A flaw was found in grub2. When performing a symlink lookup, the grub's UFS module checks the inode's data size to allocate the internal buffer to read the file content, however, it fails to check if the symlink data size has overflown. When this occurs, grub_malloc() may be called with a smaller value than needed. When further reading the data from the disk into the buffer, the grub_ufs_lookup_symlink() function will write past the end of the allocated size. An attack can leverage this by crafting a malicious filesystem, and as a result, it will corrupt data stored in the heap, allowing for arbitrary code execution used to by-pass secure boot mechanisms.

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H

跨界内存写

GNU GRUB 缓冲区错误漏洞

GNU GRUB是GNU社区的一款Linux系统引导程序。 GNU GRUB存在缓冲区错误漏洞，该漏洞源于UFS模块包含一个整数溢出问题，导致处理符号链接时发生基于堆的越界写入。

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