CVE-2021-47649

Summary

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 Software

VendorProductVersion RangeStatus
LinuxLinuxfbb0de795078190a9834b3409e4b009cfb18a6d4 < 5d50f851dd307c07ca5591297093f19967c834a9affected
LinuxLinuxfbb0de795078190a9834b3409e4b009cfb18a6d4 < b267a8118c2b171bf7d67b90ed64154eeab9fae0affected
LinuxLinuxfbb0de795078190a9834b3409e4b009cfb18a6d4 < 811b667cefbea9cb7511a874b169d6a92907137eaffected
LinuxLinuxfbb0de795078190a9834b3409e4b009cfb18a6d4 < a3728d32fc61eb0fe283cb8ff60b2c8f751e2202affected
LinuxLinuxfbb0de795078190a9834b3409e4b009cfb18a6d4 < 9e9b4a269f84d3230f2af84ff42322db676440d9affected
LinuxLinuxfbb0de795078190a9834b3409e4b009cfb18a6d4 < 2b6dd600dd72573c23ea180b5b0b2f1813405882affected
LinuxLinux4.20affected
LinuxLinux0 < 4.20unaffected
LinuxLinux5.4.189 <= 5.4.*unaffected
LinuxLinux5.10.110 <= 5.10.*unaffected
LinuxLinux5.15.33 <= 5.15.*unaffected
LinuxLinux5.16.19 <= 5.16.*unaffected
LinuxLinux5.17.2 <= 5.17.*unaffected
LinuxLinux5.18 <= *unaffected

Weaknesses

References