diff options
author | Otavio Salvador <otavio@ossystems.com.br> | 2020-05-20 08:43:03 -0300 |
---|---|---|
committer | GitHub <noreply@github.com> | 2020-05-20 08:43:03 -0300 |
commit | 1279cd128bba968ebe0a2df7f7ae38bae90250ef (patch) | |
tree | df6b1a190760f51465122ca4c13492d5ac5984c6 /drivers/staging/android/ashmem.c | |
parent | 0a8ab17689e628c84a666195bfc6ab85d11cf057 (diff) | |
parent | 2ae782ca839e0ee07de37122ddea362adff2e975 (diff) |
Merge pull request #76 from toradex/4.9-2.3.x-imx
4.9 2.3.x imx
Diffstat (limited to 'drivers/staging/android/ashmem.c')
-rw-r--r-- | drivers/staging/android/ashmem.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c index c6314d1552ea..99fd4f53c856 100644 --- a/drivers/staging/android/ashmem.c +++ b/drivers/staging/android/ashmem.c @@ -370,8 +370,23 @@ static inline vm_flags_t calc_vm_may_flags(unsigned long prot) _calc_vm_trans(prot, PROT_EXEC, VM_MAYEXEC); } +static int ashmem_vmfile_mmap(struct file *file, struct vm_area_struct *vma) +{ + /* do not allow to mmap ashmem backing shmem file directly */ + return -EPERM; +} + +static unsigned long +ashmem_vmfile_get_unmapped_area(struct file *file, unsigned long addr, + unsigned long len, unsigned long pgoff, + unsigned long flags) +{ + return current->mm->get_unmapped_area(file, addr, len, pgoff, flags); +} + static int ashmem_mmap(struct file *file, struct vm_area_struct *vma) { + static struct file_operations vmfile_fops; struct ashmem_area *asma = file->private_data; int ret = 0; @@ -412,6 +427,19 @@ static int ashmem_mmap(struct file *file, struct vm_area_struct *vma) } vmfile->f_mode |= FMODE_LSEEK; asma->file = vmfile; + /* + * override mmap operation of the vmfile so that it can't be + * remapped which would lead to creation of a new vma with no + * asma permission checks. Have to override get_unmapped_area + * as well to prevent VM_BUG_ON check for f_ops modification. + */ + if (!vmfile_fops.mmap) { + vmfile_fops = *vmfile->f_op; + vmfile_fops.mmap = ashmem_vmfile_mmap; + vmfile_fops.get_unmapped_area = + ashmem_vmfile_get_unmapped_area; + } + vmfile->f_op = &vmfile_fops; } get_file(asma->file); |