CVSS: -EPSS: 0%CPEs: 3EXPL: 0CVE-2024-50066 – mm/mremap: fix move_normal_pmd/retract_page_tables race
https://notcve.org/view.php?id=CVE-2024-50066
In the Linux kernel, the following vulnerability has been resolved: mm/mremap: fix move_normal_pmd/retract_page_tables race In mremap(), move_page_tables() looks at the type of the PMD entry and the specified address range to figure out by which method the next chunk of page table entries should be moved. At that point, the mmap_lock is held in write mode, but no rmap locks are held yet. For PMD entries that point to page tables and are fully covered by the source address range, move_pgt_entry(NORMAL_PMD, ...) is called, which first takes rmap locks, then does move_normal_pmd(). move_normal_pmd() takes the necessary page table locks at source and destination, then moves an entire page table from the source to the destination. The problem is: The rmap locks, which protect against concurrent page table removal by retract_page_tables() in the THP code, are only taken after the PMD entry has been read and it has been decided how to move it. So we can race as follows (with two processes that have mappings of the same tmpfs file that is stored on a tmpfs mount with huge=advise); note that process A accesses page tables through the MM while process B does it through the file rmap: process A process B ========= ========= mremap mremap_to move_vma move_page_tables get_old_pmd alloc_new_pmd *** PREEMPT *** madvise(MADV_COLLAPSE) do_madvise madvise_walk_vmas madvise_vma_behavior madvise_collapse hpage_collapse_scan_file collapse_file retract_page_tables i_mmap_lock_read(mapping) pmdp_collapse_flush i_mmap_unlock_read(mapping) move_pgt_entry(NORMAL_PMD, ...) take_rmap_locks move_normal_pmd drop_rmap_locks When this happens, move_normal_pmd() can end up creating bogus PMD entries in the line `pmd_populate(mm, new_pmd, pmd_pgtable(pmd))`. The effect depends on arch-specific and machine-specific details; on x86, you can end up with physical page 0 mapped as a page table, which is likely exploitable for user->kernel privilege escalation. Fix the race by letting process B recheck that the PMD still points to a page table after the rmap locks have been taken. Otherwise, we bail and let the caller fall back to the PTE-level copying path, which will then bail immediately at the pmd_none() check. Bug reachability: Reaching this bug requires that you can create shmem/file THP mappings - anonymous THP uses different code that doesn't zap stuff under rmap locks. File THP is gated on an experimental config flag (CONFIG_READ_ONLY_THP_FOR_FS), so on normal distro kernels you need shmem THP to hit this bug. • https://git.kernel.org/stable/c/1d65b771bc08cd054cf6d3766a72e113dc46d62f https://git.kernel.org/stable/c/17396e32f975130b3e6251f024c8807d192e4c3e https://git.kernel.org/stable/c/1552ce9ce8af47c0fe911682e5e1855e25851ca9 https://git.kernel.org/stable/c/6fa1066fc5d00cb9f1b0e83b7ff6ef98d26ba2aa •
CVSS: -EPSS: 0%CPEs: 7EXPL: 0CVE-2023-52918 – media: pci: cx23885: check cx23885_vdev_init() return
https://notcve.org/view.php?id=CVE-2023-52918
In the Linux kernel, the following vulnerability has been resolved: media: pci: cx23885: check cx23885_vdev_init() return cx23885_vdev_init() can return a NULL pointer, but that pointer is used in the next line without a check. Add a NULL pointer check and go to the error unwind if it is NULL. • https://git.kernel.org/stable/c/8e31b096e2e1949bc8f0be019c9ae70d414404c6 https://git.kernel.org/stable/c/199a42fc4c45e8b7f19efeb15dbc36889a599ac2 https://git.kernel.org/stable/c/e7385510e2550a9f8b6f3d5f33c5b894ab9ba976 https://git.kernel.org/stable/c/a5f1d30c51c485cec7a7de60205667c3ff86c303 https://git.kernel.org/stable/c/06ee04a907d64ee3910fecedd05d7f1be4b1b70e https://git.kernel.org/stable/c/b1397fb4a779fca560c43d2acf6702d41b4a495b https://git.kernel.org/stable/c/15126b916e39b0cb67026b0af3c014bfeb1f76b3 •
CVSS: -EPSS: 0%CPEs: 4EXPL: 0CVE-2024-50065 – ntfs3: Change to non-blocking allocation in ntfs_d_hash
https://notcve.org/view.php?id=CVE-2024-50065
In the Linux kernel, the following vulnerability has been resolved: ntfs3: Change to non-blocking allocation in ntfs_d_hash d_hash is done while under "rcu-walk" and should not sleep. __get_name() allocates using GFP_KERNEL, having the possibility to sleep when under memory pressure. Change the allocation to GFP_NOWAIT. • https://git.kernel.org/stable/c/58ebd50d22529f79d2497abbb006137a7c7f5336 https://git.kernel.org/stable/c/d392e85fd1e8d58e460c17ca7d0d5c157848d9c1 https://git.kernel.org/stable/c/2e83375fd95b81be0e9ca457cc7c3f23e3575768 https://git.kernel.org/stable/c/c556e72cea2a1131ae418be017dd6fc76fffe2fb https://git.kernel.org/stable/c/d0c710372e238510db08ea01e7b8bd81ed995dd6 https://git.kernel.org/stable/c/589996bf8c459deb5bbc9747d8f1c51658608103 •
CVSS: -EPSS: 0%CPEs: 3EXPL: 0CVE-2024-50064 – zram: free secondary algorithms names
https://notcve.org/view.php?id=CVE-2024-50064
In the Linux kernel, the following vulnerability has been resolved: zram: free secondary algorithms names We need to kfree() secondary algorithms names when reset zram device that had multi-streams, otherwise we leak memory. [senozhatsky@chromium.org: kfree(NULL) is legal] Link: https://lkml.kernel.org/r/20240917013021.868769-1-senozhatsky@chromium.org • https://git.kernel.org/stable/c/001d9273570115b2eb360d5452bbc46f6cc063a1 https://git.kernel.org/stable/c/6272936fd242ca1f784c3e21596dfb3859dff276 https://git.kernel.org/stable/c/ef35cc0d15b89dd013e1bb829fe97db7b1ab79eb https://git.kernel.org/stable/c/684826f8271ad97580b138b9ffd462005e470b99 •
CVSS: -EPSS: 0%CPEs: 3EXPL: 0CVE-2024-50063 – bpf: Prevent tail call between progs attached to different hooks
https://notcve.org/view.php?id=CVE-2024-50063
In the Linux kernel, the following vulnerability has been resolved: bpf: Prevent tail call between progs attached to different hooks bpf progs can be attached to kernel functions, and the attached functions can take different parameters or return different return values. If prog attached to one kernel function tail calls prog attached to another kernel function, the ctx access or return value verification could be bypassed. For example, if prog1 is attached to func1 which takes only 1 parameter and prog2 is attached to func2 which takes two parameters. Since verifier assumes the bpf ctx passed to prog2 is constructed based on func2's prototype, verifier allows prog2 to access the second parameter from the bpf ctx passed to it. The problem is that verifier does not prevent prog1 from passing its bpf ctx to prog2 via tail call. In this case, the bpf ctx passed to prog2 is constructed from func1 instead of func2, that is, the assumption for ctx access verification is bypassed. Another example, if BPF LSM prog1 is attached to hook file_alloc_security, and BPF LSM prog2 is attached to hook bpf_lsm_audit_rule_known. • https://git.kernel.org/stable/c/f1b9509c2fb0ef4db8d22dac9aef8e856a5d81f6 https://git.kernel.org/stable/c/5d5e3b4cbe8ee16b7bf96fd73a421c92a9da3ca1 https://git.kernel.org/stable/c/88c2a10e6c176c2860cd0659f4c0e9d20b3f64d1 https://git.kernel.org/stable/c/28ead3eaabc16ecc907cfb71876da028080f6356 •