CVE-2021-47353 Information

Description

In the Linux kernel the following vulnerability has been resolved:

udf: Fix NULL pointer dereference in udf_symlink function

In function udf_symlink epos.bh is assigned with the value returned by udf_tgetblk. The function udf_tgetblk is defined in udf/misc.c and returns the value of sb_getblk function that could be NULL. Then epos.bh is used without any check causing a possible NULL pointer dereference when sb_getblk fails.

This fix adds a check to validate the value of epos.bh.

Reference

https://git.kernel.org/stable/c/2f3d9ddd32a28803baa547e6274983b67d5e287c https://git.kernel.org/stable/c/371566f63cbd0bb6fbb25b8fe9d5798268d35af9 https://git.kernel.org/stable/c/baea588a42d675e35daeaddd10fbc9700550bc4d https://git.kernel.org/stable/c/3638705ecd5ad2785e996f820121c0ad15ce64b5 https://git.kernel.org/stable/c/80d505aee6398cf8beb72475c7edcf1733c1c68b https://git.kernel.org/stable/c/21bf1414580c36ffc8d8de043beb3508cf812238 https://git.kernel.org/stable/c/aebed6b19e51a34003d998da5ebb1dfdd2cb1d02 https://git.kernel.org/stable/c/5150877e4d99f85057a458daac7cd7c01005d5c6 https://git.kernel.org/stable/c/fa236c2b2d4436d9f19ee4e5d5924e90ffd7bb43