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CVE-2026-89996: Linux

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Вероятност да бъде експлоатирана в следващите 30 дни (EPSS)

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    Оригинално описание

    In the Linux kernel, the following vulnerability has been resolved: dma-buf: dma-heap: don't publish fd before copy_to_user() succeeds DMA_HEAP_IOCTL_ALLOC allocates a dma-buf and installs an fd into the caller's fd table via dma_buf_fd() -> fd_install() before dma_heap_ioctl() copies the result back to userspace. If the trailing copy_to_user() fails, userspace never learns the fd number, but the fd (and the underlying dma-buf reference) are already visible to other threads in the same process and are leaked for the lifetime of the process. The obvious "close it on the failure path" fix is unsafe: once fd_install() has run, another thread can already dup() the fd, send it via SCM_RIGHTS, or close() it and let its number be reused, so a subsequent close_fd() from the ioctl path can operate on an unrelated file. This was pointed out by Christian König on v1 [1]. Restructure the allocation path so that fd_install() is the last, unfailable step of a successful ioctl: 1. heap->ops->allocate() creates the dma_buf. 2. get_unused_fd_flags() reserves an fd number in the caller's fd table without publishing it, so no other thread can observe it. 3. copy_to_user() delivers the fd number to userspace; on failure the fd is returned with put_unused_fd() and the dma_buf reference is dropped with dma_buf_put(), leaving no user- visible state behind. 4. dma_buf_fd_install() publishes the fd and emits the trace_dma_buf_fd tracepoint -- from here on the ioctl cannot fail. A new dma_buf_fd_install() helper is introduced in dma-buf.c to wrap fd_install() together with the DMA_BUF_TRACE() call, preserving the export tracing that dma_buf_fd() provides. dma_heap_

    Засегнати продукти

    • Linux Linux: c02a81fba74fe3488ad6b08bfb5a1329005418f8 преди 1953ef8d11eb5870fe621259708a90900bead272; c02a81fba74fe3488ad6b08bfb5a1329005418f8 преди ad61defb3e66ac0c598ad6f39b57f15784543d46; c02a81fba74fe3488ad6b08bfb5a1329005418f8 преди 1bf6083a41f810d760c4dcd1b80c5194a92575aa; c02a81fba74fe3488ad6b08bfb5a1329005418f8 преди 69d57dbadb27ffd5eef34fd184bab145500cdabc; c02a81fba74fe3488ad6b08bfb5a1329005418f8 преди 0d4a5d218055db29b50cc07d3d73d27007c2a391; c02a81fba74fe3488ad6b08bfb5a1329005418f8 преди 30d0aff2c65a277135cfd8ea28fa1ee75e0ea4e0
    • Linux Linux: 5.6; преди 5.6; 6.1.191 до 6.1.*; 6.6.160 до 6.6.*; 6.12.112 до 6.12.*; 6.18.52 до 6.18.*; 7.2.5 до 7.2.*; 7.3 до *

    История

    • 16 септември 2026 Публикувано

    Други уязвимости в Linux Linux

    Първоизточници

    CVE-2026-89996: Linux | freedomonline.bg