From 3b8db39fad98cbb1d36e079236a446fad710daea Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Mon, 28 Jun 2021 19:38:35 -0700 Subject: mm: ignore MAP_EXECUTABLE in ksys_mmap_pgoff() Let's also remove masking off MAP_EXECUTABLE from ksys_mmap_pgoff(): the last in-tree occurrence of MAP_EXECUTABLE is now in LEGACY_MAP_MASK, which accepts the flag e.g., for MAP_SHARED_VALIDATE; however, the flag is ignored throughout the kernel now. Add a comment to LEGACY_MAP_MASK stating that MAP_EXECUTABLE is ignored. Link: https://lkml.kernel.org/r/20210421093453.6904-4-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: "Eric W. Biederman" Reviewed-by: Kees Cook Cc: Alexander Shishkin Cc: Alexander Viro Cc: Arnaldo Carvalho de Melo Cc: Borislav Petkov Cc: Catalin Marinas Cc: Don Zickus Cc: Feng Tang Cc: Greg Ungerer Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kevin Brodsky Cc: Mark Rutland Cc: Michal Hocko Cc: Mike Rapoport Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'mm/mmap.c') diff --git a/mm/mmap.c b/mm/mmap.c index 0584e540246e..f9a61f7dc540 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1633,7 +1633,7 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len, return PTR_ERR(file); } - flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE); + flags &= ~MAP_DENYWRITE; retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); out_fput: -- cgit v1.2.3 From 78d9cf6041b968cc881fd22e25e2662d1cec4dba Mon Sep 17 00:00:00 2001 From: Gonzalo Matias Juarez Tello Date: Mon, 28 Jun 2021 19:38:39 -0700 Subject: mm/mmap.c: logic of find_vma_intersection repeated in __do_munmap Logic of find_vma_intersection() is repeated in __do_munmap(). Also, prev is assigned a value before checking vma->vm_start >= end which might end up on a return statement making that assignment useless. Calling find_vma_intersection() checks that condition and returns NULL if no vma is found, hence only the !vma check is needed in __do_munmap(). Link: https://lkml.kernel.org/r/20210409162129.18313-1-gmjuareztello@gmail.com Signed-off-by: Gonzalo Matias Juarez Tello Reviewed-by: Andrew Morton Reviewed-by: David Hildenbrand Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) (limited to 'mm/mmap.c') diff --git a/mm/mmap.c b/mm/mmap.c index f9a61f7dc540..bb128a42557e 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2828,16 +2828,11 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len, */ arch_unmap(mm, start, end); - /* Find the first overlapping VMA */ - vma = find_vma(mm, start); + /* Find the first overlapping VMA where start < vma->vm_end */ + vma = find_vma_intersection(mm, start, end); if (!vma) return 0; prev = vma->vm_prev; - /* we have start < vma->vm_end */ - - /* if it doesn't overlap, we have nothing.. */ - if (vma->vm_start >= end) - return 0; /* * If we need to split any vma, do it now to save pain later. -- cgit v1.2.3 From 96d990239e31d9623fdb96e829237b997c9d3d63 Mon Sep 17 00:00:00 2001 From: Liam Howlett Date: Mon, 28 Jun 2021 19:38:41 -0700 Subject: mm/mmap: introduce unlock_range() for code cleanup Both __do_munmap() and exit_mmap() unlock a range of VMAs using almost identical code blocks. Replace both blocks by a static inline function. [akpm@linux-foundation.org: tweak code layout] Link: https://lkml.kernel.org/r/20210510211021.2797427-1-Liam.Howlett@Oracle.com Signed-off-by: Liam R. Howlett Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: Davidlohr Bueso Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 39 ++++++++++++++++++++------------------- 1 file changed, 20 insertions(+), 19 deletions(-) (limited to 'mm/mmap.c') diff --git a/mm/mmap.c b/mm/mmap.c index bb128a42557e..d72716f7a0b4 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2802,6 +2802,22 @@ int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, return __split_vma(mm, vma, addr, new_below); } +static inline void +unlock_range(struct vm_area_struct *start, unsigned long limit) +{ + struct mm_struct *mm = start->vm_mm; + struct vm_area_struct *tmp = start; + + while (tmp && tmp->vm_start < limit) { + if (tmp->vm_flags & VM_LOCKED) { + mm->locked_vm -= vma_pages(tmp); + munlock_vma_pages_all(tmp); + } + + tmp = tmp->vm_next; + } +} + /* Munmap is split into 2 main parts -- this part which finds * what needs doing, and the areas themselves, which do the * work. This now handles partial unmappings. @@ -2885,17 +2901,8 @@ int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len, /* * unlock any mlock()ed ranges before detaching vmas */ - if (mm->locked_vm) { - struct vm_area_struct *tmp = vma; - while (tmp && tmp->vm_start < end) { - if (tmp->vm_flags & VM_LOCKED) { - mm->locked_vm -= vma_pages(tmp); - munlock_vma_pages_all(tmp); - } - - tmp = tmp->vm_next; - } - } + if (mm->locked_vm) + unlock_range(vma, end); /* Detach vmas from rbtree */ if (!detach_vmas_to_be_unmapped(mm, vma, prev, end)) @@ -3180,14 +3187,8 @@ void exit_mmap(struct mm_struct *mm) mmap_write_unlock(mm); } - if (mm->locked_vm) { - vma = mm->mmap; - while (vma) { - if (vma->vm_flags & VM_LOCKED) - munlock_vma_pages_all(vma); - vma = vma->vm_next; - } - } + if (mm->locked_vm) + unlock_range(mm->mmap, ULONG_MAX); arch_exit_mmap(mm); -- cgit v1.2.3 From 35e43c5ff4d2da700e8ed2216acae81f62800eaa Mon Sep 17 00:00:00 2001 From: Liam Howlett Date: Mon, 28 Jun 2021 19:38:44 -0700 Subject: mm/mmap: use find_vma_intersection() in do_mmap() for overlap Using find_vma_intersection() avoids the need for a temporary variable and makes the code cleaner. Link: https://lkml.kernel.org/r/20210511014328.2902782-1-Liam.Howlett@Oracle.com Signed-off-by: Liam R. Howlett Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'mm/mmap.c') diff --git a/mm/mmap.c b/mm/mmap.c index d72716f7a0b4..d8c92ae50565 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1457,9 +1457,7 @@ unsigned long do_mmap(struct file *file, unsigned long addr, return addr; if (flags & MAP_FIXED_NOREPLACE) { - struct vm_area_struct *vma = find_vma(mm, addr); - - if (vma && vma->vm_start < addr + len) + if (find_vma_intersection(mm, addr, addr + len)) return -EEXIST; } -- cgit v1.2.3