d1811067ee
[ Upstream commit 5baf8b037debf4ec60108ccfeccb8636d1dbad81 ] Currently MTE is permitted in two circumstances (desiring to use MTE having been specified by the VM_MTE flag) - where MAP_ANONYMOUS is specified, as checked by arch_calc_vm_flag_bits() and actualised by setting the VM_MTE_ALLOWED flag, or if the file backing the mapping is shmem, in which case we set VM_MTE_ALLOWED in shmem_mmap() when the mmap hook is activated in mmap_region(). The function that checks that, if VM_MTE is set, VM_MTE_ALLOWED is also set is the arm64 implementation of arch_validate_flags(). Unfortunately, we intend to refactor mmap_region() to perform this check earlier, meaning that in the case of a shmem backing we will not have invoked shmem_mmap() yet, causing the mapping to fail spuriously. It is inappropriate to set this architecture-specific flag in general mm code anyway, so a sensible resolution of this issue is to instead move the check somewhere else. We resolve this by setting VM_MTE_ALLOWED much earlier in do_mmap(), via the arch_calc_vm_flag_bits() call. This is an appropriate place to do this as we already check for the MAP_ANONYMOUS case here, and the shmem file case is simply a variant of the same idea - we permit RAM-backed memory. This requires a modification to the arch_calc_vm_flag_bits() signature to pass in a pointer to the struct file associated with the mapping, however this is not too egregious as this is only used by two architectures anyway - arm64 and parisc. So this patch performs this adjustment and removes the unnecessary assignment of VM_MTE_ALLOWED in shmem_mmap(). [akpm@linux-foundation.org: fix whitespace, per Catalin] Link: https://lkml.kernel.org/r/ec251b20ba1964fb64cf1607d2ad80c47f3873df.1730224667.git.lorenzo.stoakes@oracle.com Fixes: deb0f6562884 ("mm/mmap: undo ->mmap() when arch_validate_flags() fails") Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Suggested-by: Catalin Marinas <catalin.marinas@arm.com> Reported-by: Jann Horn <jannh@google.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Cc: Andreas Larsson <andreas@gaisler.com> Cc: David S. Miller <davem@davemloft.net> Cc: Helge Deller <deller@gmx.de> Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com> Cc: Liam R. Howlett <Liam.Howlett@oracle.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mark Brown <broonie@kernel.org> Cc: Peter Xu <peterx@redhat.com> Cc: Will Deacon <will@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
162 lines
3.9 KiB
C
Executable file
162 lines
3.9 KiB
C
Executable file
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_MMAN_H
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#define _LINUX_MMAN_H
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/percpu_counter.h>
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#include <linux/atomic.h>
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#include <uapi/linux/mman.h>
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/*
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* Arrange for legacy / undefined architecture specific flags to be
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* ignored by mmap handling code.
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*/
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#ifndef MAP_32BIT
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#define MAP_32BIT 0
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#endif
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#ifndef MAP_HUGE_2MB
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#define MAP_HUGE_2MB 0
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#endif
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#ifndef MAP_HUGE_1GB
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#define MAP_HUGE_1GB 0
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#endif
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#ifndef MAP_UNINITIALIZED
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#define MAP_UNINITIALIZED 0
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#endif
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#ifndef MAP_SYNC
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#define MAP_SYNC 0
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#endif
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/*
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* The historical set of flags that all mmap implementations implicitly
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* support when a ->mmap_validate() op is not provided in file_operations.
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*/
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#define LEGACY_MAP_MASK (MAP_SHARED \
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| MAP_PRIVATE \
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| MAP_FIXED \
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| MAP_ANONYMOUS \
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| MAP_DENYWRITE \
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| MAP_EXECUTABLE \
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| MAP_UNINITIALIZED \
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| MAP_GROWSDOWN \
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| MAP_LOCKED \
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| MAP_NORESERVE \
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| MAP_POPULATE \
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| MAP_NONBLOCK \
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| MAP_STACK \
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| MAP_HUGETLB \
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| MAP_32BIT \
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| MAP_HUGE_2MB \
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| MAP_HUGE_1GB)
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extern int sysctl_overcommit_memory;
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extern int sysctl_overcommit_ratio;
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extern unsigned long sysctl_overcommit_kbytes;
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extern struct percpu_counter vm_committed_as;
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#ifdef CONFIG_SMP
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extern s32 vm_committed_as_batch;
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extern void mm_compute_batch(int overcommit_policy);
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#else
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#define vm_committed_as_batch 0
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static inline void mm_compute_batch(int overcommit_policy)
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{
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}
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#endif
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unsigned long vm_memory_committed(void);
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static inline void vm_acct_memory(long pages)
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{
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percpu_counter_add_batch(&vm_committed_as, pages, vm_committed_as_batch);
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}
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static inline void vm_unacct_memory(long pages)
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{
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vm_acct_memory(-pages);
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}
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/*
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* Allow architectures to handle additional protection and flag bits. The
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* overriding macros must be defined in the arch-specific asm/mman.h file.
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*/
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#ifndef arch_calc_vm_prot_bits
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#define arch_calc_vm_prot_bits(prot, pkey) 0
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#endif
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#ifndef arch_calc_vm_flag_bits
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#define arch_calc_vm_flag_bits(file, flags) 0
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#endif
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#ifndef arch_vm_get_page_prot
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#define arch_vm_get_page_prot(vm_flags) __pgprot(0)
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#endif
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#ifndef arch_validate_prot
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/*
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* This is called from mprotect(). PROT_GROWSDOWN and PROT_GROWSUP have
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* already been masked out.
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*
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* Returns true if the prot flags are valid
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*/
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static inline bool arch_validate_prot(unsigned long prot, unsigned long addr)
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{
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return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
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}
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#define arch_validate_prot arch_validate_prot
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#endif
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#ifndef arch_validate_flags
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/*
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* This is called from mmap() and mprotect() with the updated vma->vm_flags.
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*
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* Returns true if the VM_* flags are valid.
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*/
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static inline bool arch_validate_flags(unsigned long flags)
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{
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return true;
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}
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#define arch_validate_flags arch_validate_flags
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#endif
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/*
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* Optimisation macro. It is equivalent to:
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* (x & bit1) ? bit2 : 0
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* but this version is faster.
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* ("bit1" and "bit2" must be single bits)
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*/
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#define _calc_vm_trans(x, bit1, bit2) \
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((!(bit1) || !(bit2)) ? 0 : \
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((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
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: ((x) & (bit1)) / ((bit1) / (bit2))))
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/*
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* Combine the mmap "prot" argument into "vm_flags" used internally.
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*/
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static inline unsigned long
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calc_vm_prot_bits(unsigned long prot, unsigned long pkey)
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{
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return _calc_vm_trans(prot, PROT_READ, VM_READ ) |
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_calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
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_calc_vm_trans(prot, PROT_EXEC, VM_EXEC) |
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arch_calc_vm_prot_bits(prot, pkey);
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}
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/*
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* Combine the mmap "flags" argument into "vm_flags" used internally.
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*/
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static inline unsigned long
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calc_vm_flag_bits(struct file *file, unsigned long flags)
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{
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return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) |
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_calc_vm_trans(flags, MAP_DENYWRITE, VM_DENYWRITE ) |
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_calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED ) |
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_calc_vm_trans(flags, MAP_SYNC, VM_SYNC ) |
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arch_calc_vm_flag_bits(file, flags);
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}
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unsigned long vm_commit_limit(void);
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#endif /* _LINUX_MMAN_H */
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