daemon: Decompress archives before entering container filesystem - #11
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val4oss wants to merge 1 commit into
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daemon: Decompress archives before entering container filesystem#11val4oss wants to merge 1 commit into
val4oss wants to merge 1 commit into
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Move decompression outside RunInFS to prevent executing
attacker-controlled binaries from within the container filesystem.
When dockerd handles `PUT /containers/{id}/archive`, it switches root
into the container's filesystem before extracting the archive.
Previously, archive.Untar was called inside RunInFS, which meant
decompression binaries (xz, unpigz) were resolved via PATH inside the
container's filesystem. A malicious binary at /usr/bin/xz in the
container would be executed as host root.
Fix by calling decompressing the archive before entering the container
filesystem, then using unpacking the uncompressed tar stream inside
RunInFS.
This ensures decompression binaries are always resolved from the host
filesystem.
Signed-off-by: Paweł Gronowski <[email protected]>
(cherry picked from commit 2022313)
[vlefebvre: fixes bsc#1267827 CVE-2026-41567]
danishprakash
approved these changes
Jun 12, 2026
|
Lets not merge it now. |
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Move decompression outside RunInFS to prevent executing attacker-controlled binaries from within the container filesystem.
When dockerd handles
PUT /containers/{id}/archive, it switches root into the container's filesystem before extracting the archive. Previously, archive.Untar was called inside RunInFS, which meant decompression binaries (xz, unpigz) were resolved via PATH inside the container's filesystem. A malicious binary at /usr/bin/xz in the container would be executed as host root.Fix by calling decompressing the archive before entering the container filesystem, then using unpacking the uncompressed tar stream inside RunInFS.
This ensures decompression binaries are always resolved from the host filesystem.
Signed-off-by: Paweł Gronowski [email protected]
(cherry picked from commit 2022313)
[vlefebvre: fixes bsc#1267827 CVE-2026-41567]
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