io_uring: fix filename leak in __io_openat_prep()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: io_uring: fix filename leak in __io_openat_prep() __io_openat_prep() allocates a struct filename using getname(). However, for the condition of the file being installed in the fixed file table as well as having O_CLOEXEC flag set, the function returns early. At that point, the request doesn't have REQ_F_NEED_CLEANUP flag set. Due to this, the memory for the newly allocated struct filename is not cleaned up, causing a memory leak. Fix this by setting the REQ_F_NEED_CLEANUP for the request just after the successful getname() call, so that when the request is torn down, the filename will be cleaned up, along with other resources needing cleanup.

References

• https://git.kernel.org/stable/c/2420ef01b2e836fbc05a0a8c73a1016504eb0458
• https://git.kernel.org/stable/c/8f44c4a550570cd5903625133f938c6b51310c9b
• https://git.kernel.org/stable/c/18b99fa603d0df5e1c898699c17d3b92ddc80746
• https://git.kernel.org/stable/c/e232269d511566b1f80872256a48593acc1becf4
• https://git.kernel.org/stable/c/7fbfb85b05bc960cc50e09d03e5e562131e48d45
• https://git.kernel.org/stable/c/b14fad555302a2104948feaff70503b64c80ac01