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medium5.5

CVE-2021-47649

In the Linux kernel, the following vulnerability has been resolved: udmabuf: validate ubuf->pagecount Syzbot has reported GPF in sg_alloc_append_table_from_pag…

Impact

In the Linux kernel, the following vulnerability has been resolved: udmabuf: validate ubuf->pagecount Syzbot has reported GPF in sg_alloc_append_table_from_pages(). The problem was in ubuf->pages == ZERO_PTR. ubuf->pagecount is calculated from arguments passed from user-space. If user creates udmabuf with list.size == 0 then ubuf->pagecount will be also equal to zero; it causes kmalloc_array() to return ZERO_PTR. Fix it by validating ubuf->pagecount before passing it to kmalloc_array().

Affected products

VendorProductAffected versions
LinuxLinux Kernel
from 4.20 before 5.4.189
from 5.5 before 5.10.110
from 5.11 before 5.15.33
from 5.16 before 5.16.19
from 5.17 before 5.17.2

References