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author | David Hildenbrand <david@redhat.com> | 2021-04-23 10:29:59 +0200 |
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committer | David Hildenbrand <david@redhat.com> | 2021-09-03 18:42:01 +0200 |
commit | fe69d560b5bd9ec77b5d5749bd7027344daef47e (patch) | |
tree | d326cdd1de311c30c88008ffd2f1f3a9ac34e227 /fs/ioctl.c | |
parent | kernel/fork: factor out replacing the current MM exe_file (diff) | |
download | linux-fe69d560b5bd9ec77b5d5749bd7027344daef47e.tar.xz linux-fe69d560b5bd9ec77b5d5749bd7027344daef47e.zip |
kernel/fork: always deny write access to current MM exe_file
We want to remove VM_DENYWRITE only currently only used when mapping the
executable during exec. During exec, we already deny_write_access() the
executable, however, after exec completes the VMAs mapped
with VM_DENYWRITE effectively keeps write access denied via
deny_write_access().
Let's deny write access when setting or replacing the MM exe_file. With
this change, we can remove VM_DENYWRITE for mapping executables.
Make set_mm_exe_file() return an error in case deny_write_access()
fails; note that this should never happen, because exec code does a
deny_write_access() early and keeps write access denied when calling
set_mm_exe_file. However, it makes the code easier to read and makes
set_mm_exe_file() and replace_mm_exe_file() look more similar.
This represents a minor user space visible change:
sys_prctl(PR_SET_MM_MAP/EXE_FILE) can now fail if the file is already
opened writable. Also, after sys_prctl(PR_SET_MM_MAP/EXE_FILE) the file
cannot be opened writable. Note that we can already fail with -EACCES if
the file doesn't have execute permissions.
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Diffstat (limited to 'fs/ioctl.c')
0 files changed, 0 insertions, 0 deletions