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fs_mgr: overlayfs: requires override_creds patch for 4.4+ kernels (taimen)

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The original adb-remount-test.sh when certifying kernels allowed a
pass on 4.4 kernels because it added new content, and missed a test
for overriding existing content.  When the test was added to confirm
APEX control of libc.so, it serendipitously added a check for
overriding existing content, which the 4.4 kernel did not allow to
pass.  Update the tests and documentation to reflect this new state
of affairs.

Summary: 4.4 kernel overlayfs driver worked partially without the
patch for override_creds.

Test: adb-remount-test.sh
Bug: 126256072
Change-Id: I979ea59a12bc0b9926826b9b09a7893ab3b9ee7f
This commit is contained in:
Mark Salyzyn 2019-02-26 08:39:40 -08:00
parent 89a7cc48cc
commit a9451a5db1
3 changed files with 12 additions and 15 deletions
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2
fs_mgr/README.overlayfs.md
View file

@ -94,7 +94,7 @@ Caveats
and thus free dynamic partition space.
- Kernel must have CONFIG_OVERLAY_FS=y and will need to be patched
with "*overlayfs: override_creds=off option bypass creator_cred*"
if kernel is higher than 4.6.
if kernel is 4.4 or higher.
The patch is available on the upstream mailing list and the latest as of
Feb 8 2019 is https://lore.kernel.org/patchwork/patch/1009299/.
This patch adds an override_creds _mount_ option to overlayfs that

2
fs_mgr/fs_mgr_overlayfs.cpp
View file

@ -1031,7 +1031,7 @@ OverlayfsValidResult fs_mgr_overlayfs_valid() {
if (major > 4) {
return OverlayfsValidResult::kNotSupported;
}
if (minor > 6) {
if (minor > 3) {
return OverlayfsValidResult::kNotSupported;
}
return OverlayfsValidResult::kOk;

23
fs_mgr/tests/adb-remount-test.sh
View file

@ -577,20 +577,17 @@ adb_sh ls -d /sys/module/overlay </dev/null >/dev/null 2>/dev/null ||
) ||
overlayfs_supported=false
if ${overlayfs_supported}; then
case `adb_sh uname -r </dev/null` in
4.[6789].* | 4.[1-9][0-9]* | [56789].*)
adb_su ls /sys/module/overlay/parameters/override_creds </dev/null >/dev/null &&
echo "${GREEN}[ OK ]${NORMAL} overlay module supports override_creds" >&2 ||
(
echo "${ORANGE}[ WARNING ]${NORMAL} overlay module does not support override_creds" >&2 &&
false
) ||
adb_su ls /sys/module/overlay/parameters/override_creds </dev/null >/dev/null &&
echo "${GREEN}[ OK ]${NORMAL} overlay module supports override_creds" >&2 ||
case `adb_sh uname -r </dev/null` in
4.[456789].* | 4.[1-9][0-9]* | [56789].*)
echo "${ORANGE}[ WARNING ]${NORMAL} overlay module does not support override_creds" >&2 &&
overlayfs_supported=false
;;
*)
echo "${GREEN}[ OK ]${NORMAL} overlay module uses callers creds" >&2
;;
esac
;;
*)
echo "${GREEN}[ OK ]${NORMAL} overlay module uses caller's creds" >&2
;;
esac
fi
adb_root ||