Description
In the Linux kernel, the following vulnerability has been resolved: xen: fix UAF in dmabuf_exp_from_pages() [dma_buf_fd() fixes; no preferences regarding the tree it goes through - up to xen folks] As soon as we'd inserted a file reference into descriptor table, another thread could close it. That's fine for the case when all we are doing is returning that descriptor to userland (it's a race, but it's a userland race and there's nothing the kernel can do about it). However, if we follow fd_install() with any kind of access to objects that would be destroyed on close (be it the struct file itself or anything destroyed by its ->release()), we have a UAF. dma_buf_fd() is a combination of reserving a descriptor and fd_install(). gntdev dmabuf_exp_from_pages() calls it and then proceeds to access the objects destroyed on close - starting with gntdev_dmabuf itself. Fix that by doing reserving descriptor before anything else and do fd_install() only when everything had been set up.
Product status
a240d6e42e28c34fdc34b3a98ca838a31c939901 before e5907885260401bba300d4d18d79875c05b82651
a240d6e42e28c34fdc34b3a98ca838a31c939901 before 3edfd2353f301bfffd5ee41066e37320a59ccc2d
a240d6e42e28c34fdc34b3a98ca838a31c939901 before d59d49af4aeed9a81e673e37c26c6a3bacf1a181
a240d6e42e28c34fdc34b3a98ca838a31c939901 before 532c8b51b3a8676cbf533a291f8156774f30ea87
4.19
Any version before 4.19
6.12.42
6.15.10
6.16.1
6.17
References
git.kernel.org/...c/e5907885260401bba300d4d18d79875c05b82651
git.kernel.org/...c/3edfd2353f301bfffd5ee41066e37320a59ccc2d
git.kernel.org/...c/d59d49af4aeed9a81e673e37c26c6a3bacf1a181
git.kernel.org/...c/532c8b51b3a8676cbf533a291f8156774f30ea87
