Fix failure with read-only /dev in spec#3276
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cyphar merged 2 commits intoopencontainers:masterfrom Nov 25, 2021
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Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
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Commit fb4c27c (went into v1.0.0-rc93) fixed a bug with read-only tmpfs, but introduced a bug with read-only /dev. This happens because /dev is a tmpfs mount and is therefore remounted read-only a bit earlier than before. To fix, 1. Revert the part of the above commit which remounts all tmpfs mounts as read-only in mountToRootfs. 2. Reuse finalizeRootfs (which is already used to remount /dev read-only) to also remount all ro tmpfs mounts that were previously mounted rw in mountPropagate. 3. Remove the break in finalizeRootfs, as now we have more than one mount to care about. 4. Reorder the if statements in finalizeRootfs to perform the fast check (for ro flag) first, and compare the strings second. Since /dev is most probably also a tmpfs mount, do the m.Device check first. Add a test case to validate the fix and prevent future regressions; make sure it fails before the fix: ✗ runc run [ro /dev mount] (in test file tests/integration/mounts.bats, line 45) `[ "$status" -eq 0 ]' failed runc spec (status=0): runc run test_busybox (status=1): time="2021-11-12T12:19:48-08:00" level=error msg="runc run failed: unable to start container process: error during container init: error mounting \"devpts\" to rootfs at \"/dev/pts\": mkdir /tmp/bats-run-VJXQk7/runc.0Fj70w/bundle/rootfs/dev/pts: read-only file system" Fixes: fb4c27c Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
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@AkihiroSuda @cyphar PTAL |
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@AkihiroSuda PTAL |
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Commit fb4c27c (PR #2570, went into v1.0.0-rc93) fixed a bug with
read-only tmpfs, but introduced a bug with read-only /dev (#3248).
This happens because /dev is a tmpfs mount and is therefore remounted
read-only a bit earlier than before.
To fix,
Revert the part of the above commit which remounts all tmpfs mounts
as read-only in mountToRootfs.
Reuse finalizeRootfs (which is already used to remount /dev
read-only) to also remount all ro tmpfs mounts that were previously
mounted rw in mountPropagate.
Add a test case to validate the fix and prevent future regressions;
make sure it fails before the fix:
Fixes: #3248
1.0 backport: #3277