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mm: untag user pointers in mmap/munmap/mremap/brk

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There isn't a good reason to differentiate between the user address space
layout modification syscalls and the other memory permission/attributes
ones (e.g.  mprotect, madvise) w.r.t.  the tagged address ABI.  Untag the
user addresses on entry to these functions.

Link: http://lkml.kernel.org/r/20190821164730.47450-2-catalin.marinas@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Szabolcs Nagy <szabolcs.nagy@arm.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Cc: Dave P Martin <Dave.Martin@arm.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Catalin Marinas 2019-09-25 16:49:04 -07:00 committed by Linus Torvalds
parent 6cf5354c1c
commit ce18d171cb
2 changed files with 6 additions and 5 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

5
mm/mmap.c
View file

@ -201,6 +201,8 @@ SYSCALL_DEFINE1(brk, unsigned long, brk)
bool downgraded = false;
LIST_HEAD(uf);
brk = untagged_addr(brk);
if (down_write_killable(&mm->mmap_sem))
return -EINTR;
@ -1587,6 +1589,8 @@ unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
struct file *file = NULL;
unsigned long retval;
addr = untagged_addr(addr);
if (!(flags & MAP_ANONYMOUS)) {
audit_mmap_fd(fd, flags);
file = fget(fd);
@ -2885,6 +2889,7 @@ EXPORT_SYMBOL(vm_munmap);
SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
{
addr = untagged_addr(addr);
profile_munmap(addr);
return __vm_munmap(addr, len, true);
}

6
mm/mremap.c
View file

@ -606,12 +606,8 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
LIST_HEAD(uf_unmap_early);
LIST_HEAD(uf_unmap);
/*
* Architectures may interpret the tag passed to mmap as a background
* colour for the corresponding vma. For mremap we don't allow tagged
* new_addr to preserve similar behaviour to mmap.
*/
addr = untagged_addr(addr);
new_addr = untagged_addr(new_addr);
if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
return ret;