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https://github.com/edk2-porting/linux-next.git
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3234ac664a
Close the hole of holding a mapping over kernel driver takeover event of a given address range. Commit90a545e981("restrict /dev/mem to idle io memory ranges") introduced CONFIG_IO_STRICT_DEVMEM with the goal of protecting the kernel against scenarios where a /dev/mem user tramples memory that a kernel driver owns. However, this protection only prevents *new* read(), write() and mmap() requests. Established mappings prior to the driver calling request_mem_region() are left alone. Especially with persistent memory, and the core kernel metadata that is stored there, there are plentiful scenarios for a /dev/mem user to violate the expectations of the driver and cause amplified damage. Teach request_mem_region() to find and shoot down active /dev/mem mappings that it believes it has successfully claimed for the exclusive use of the driver. Effectively a driver call to request_mem_region() becomes a hole-punch on the /dev/mem device. The typical usage of unmap_mapping_range() is part of truncate_pagecache() to punch a hole in a file, but in this case the implementation is only doing the "first half" of a hole punch. Namely it is just evacuating current established mappings of the "hole", and it relies on the fact that /dev/mem establishes mappings in terms of absolute physical address offsets. Once existing mmap users are invalidated they can attempt to re-establish the mapping, or attempt to continue issuing read(2) / write(2) to the invalidated extent, but they will then be subject to the CONFIG_IO_STRICT_DEVMEM checking that can block those subsequent accesses. Cc: Arnd Bergmann <arnd@arndb.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Kees Cook <keescook@chromium.org> Cc: Matthew Wilcox <willy@infradead.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Fixes:90a545e981("restrict /dev/mem to idle io memory ranges") Signed-off-by: Dan Williams <dan.j.williams@intel.com> Reviewed-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/159009507306.847224.8502634072429766747.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
102 lines
3.6 KiB
C
102 lines
3.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
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#ifndef __LINUX_MAGIC_H__
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#define __LINUX_MAGIC_H__
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#define ADFS_SUPER_MAGIC 0xadf5
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#define AFFS_SUPER_MAGIC 0xadff
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#define AFS_SUPER_MAGIC 0x5346414F
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#define AUTOFS_SUPER_MAGIC 0x0187
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#define CODA_SUPER_MAGIC 0x73757245
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#define CRAMFS_MAGIC 0x28cd3d45 /* some random number */
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#define CRAMFS_MAGIC_WEND 0x453dcd28 /* magic number with the wrong endianess */
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#define DEBUGFS_MAGIC 0x64626720
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#define SECURITYFS_MAGIC 0x73636673
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#define SELINUX_MAGIC 0xf97cff8c
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#define SMACK_MAGIC 0x43415d53 /* "SMAC" */
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#define RAMFS_MAGIC 0x858458f6 /* some random number */
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#define TMPFS_MAGIC 0x01021994
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#define HUGETLBFS_MAGIC 0x958458f6 /* some random number */
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#define SQUASHFS_MAGIC 0x73717368
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#define ECRYPTFS_SUPER_MAGIC 0xf15f
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#define EFS_SUPER_MAGIC 0x414A53
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#define EROFS_SUPER_MAGIC_V1 0xE0F5E1E2
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#define EXT2_SUPER_MAGIC 0xEF53
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#define EXT3_SUPER_MAGIC 0xEF53
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#define XENFS_SUPER_MAGIC 0xabba1974
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#define EXT4_SUPER_MAGIC 0xEF53
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#define BTRFS_SUPER_MAGIC 0x9123683E
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#define NILFS_SUPER_MAGIC 0x3434
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#define F2FS_SUPER_MAGIC 0xF2F52010
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#define HPFS_SUPER_MAGIC 0xf995e849
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#define ISOFS_SUPER_MAGIC 0x9660
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#define JFFS2_SUPER_MAGIC 0x72b6
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#define XFS_SUPER_MAGIC 0x58465342 /* "XFSB" */
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#define PSTOREFS_MAGIC 0x6165676C
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#define EFIVARFS_MAGIC 0xde5e81e4
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#define HOSTFS_SUPER_MAGIC 0x00c0ffee
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#define OVERLAYFS_SUPER_MAGIC 0x794c7630
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#define MINIX_SUPER_MAGIC 0x137F /* minix v1 fs, 14 char names */
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#define MINIX_SUPER_MAGIC2 0x138F /* minix v1 fs, 30 char names */
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#define MINIX2_SUPER_MAGIC 0x2468 /* minix v2 fs, 14 char names */
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#define MINIX2_SUPER_MAGIC2 0x2478 /* minix v2 fs, 30 char names */
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#define MINIX3_SUPER_MAGIC 0x4d5a /* minix v3 fs, 60 char names */
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#define MSDOS_SUPER_MAGIC 0x4d44 /* MD */
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#define NCP_SUPER_MAGIC 0x564c /* Guess, what 0x564c is :-) */
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#define NFS_SUPER_MAGIC 0x6969
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#define OCFS2_SUPER_MAGIC 0x7461636f
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#define OPENPROM_SUPER_MAGIC 0x9fa1
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#define QNX4_SUPER_MAGIC 0x002f /* qnx4 fs detection */
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#define QNX6_SUPER_MAGIC 0x68191122 /* qnx6 fs detection */
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#define AFS_FS_MAGIC 0x6B414653
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#define REISERFS_SUPER_MAGIC 0x52654973 /* used by gcc */
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/* used by file system utilities that
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look at the superblock, etc. */
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#define REISERFS_SUPER_MAGIC_STRING "ReIsErFs"
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#define REISER2FS_SUPER_MAGIC_STRING "ReIsEr2Fs"
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#define REISER2FS_JR_SUPER_MAGIC_STRING "ReIsEr3Fs"
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#define SMB_SUPER_MAGIC 0x517B
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#define CGROUP_SUPER_MAGIC 0x27e0eb
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#define CGROUP2_SUPER_MAGIC 0x63677270
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#define RDTGROUP_SUPER_MAGIC 0x7655821
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#define STACK_END_MAGIC 0x57AC6E9D
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#define TRACEFS_MAGIC 0x74726163
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#define V9FS_MAGIC 0x01021997
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#define BDEVFS_MAGIC 0x62646576
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#define DAXFS_MAGIC 0x64646178
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#define BINFMTFS_MAGIC 0x42494e4d
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#define DEVPTS_SUPER_MAGIC 0x1cd1
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#define BINDERFS_SUPER_MAGIC 0x6c6f6f70
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#define FUTEXFS_SUPER_MAGIC 0xBAD1DEA
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#define PIPEFS_MAGIC 0x50495045
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#define PROC_SUPER_MAGIC 0x9fa0
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#define SOCKFS_MAGIC 0x534F434B
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#define SYSFS_MAGIC 0x62656572
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#define USBDEVICE_SUPER_MAGIC 0x9fa2
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#define MTD_INODE_FS_MAGIC 0x11307854
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#define ANON_INODE_FS_MAGIC 0x09041934
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#define BTRFS_TEST_MAGIC 0x73727279
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#define NSFS_MAGIC 0x6e736673
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#define BPF_FS_MAGIC 0xcafe4a11
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#define AAFS_MAGIC 0x5a3c69f0
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#define ZONEFS_MAGIC 0x5a4f4653
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/* Since UDF 2.01 is ISO 13346 based... */
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#define UDF_SUPER_MAGIC 0x15013346
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#define BALLOON_KVM_MAGIC 0x13661366
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#define ZSMALLOC_MAGIC 0x58295829
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#define DMA_BUF_MAGIC 0x444d4142 /* "DMAB" */
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#define DEVMEM_MAGIC 0x454d444d /* "DMEM" */
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#define Z3FOLD_MAGIC 0x33
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#define PPC_CMM_MAGIC 0xc7571590
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#endif /* __LINUX_MAGIC_H__ */
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