path: root/CHANGES
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authorGravatar Thomas Petazzoni <thomas.petazzoni@free-electrons.com>2016-09-15 10:58:28 +0200
committerGravatar Peter Korsgaard <peter@korsgaard.com>2016-09-20 15:12:04 +0200
commitdcd36d47d2416e1c713849a8b95fa5e6e8530b51 (patch)
treedf7d44b969ac2ec5e48fb6a46578a69bcb32bcd6 /CHANGES
parent78e991462868e8f86d20754cf05a79f2b6be395c (diff)
toolchain-external: fix potential entire root filesystem removal
This reverts commit a0aa7e0e1750f6ace2879ea8adb1425a41431b79 and reworks the code to fix a major and potentially catastrophic bug when the following conditions are met: - The user has selected a "known toolchain profile", such as a Linaro toolchain, a Sourcery CodeBench toolchain etc. People using "custom toolchain profile" are not affected. - The user has enabled BR2_TOOLCHAIN_EXTERNAL_PREINSTALLED=y to indicate that the toolchain is already locally available (as opposed to having Buildroot download and extract the toolchain) - The user has left BR2_TOOLCHAIN_EXTERNAL_PATH empty, because his toolchain is directly available through the PATH environment variable. When BR2_TOOLCHAIN_EXTERNAL_PATH is non-empty, Buildroot will do something silly (remove the toolchain contents), but that are limited to the toolchain itself. When such conditions are met, Buildroot will run "rm -rf /*" due to TOOLCHAIN_EXTERNAL_INSTALL_DIR being empty. This bug does not exist in 2016.05, and appeared in 2016.08 due to commit a0aa7e0e1750f6ace2879ea8adb1425a41431b79. Commit a0aa7e0e1750f6ace2879ea8adb1425a41431b79 removed the assignment of TOOLCHAIN_EXTERNAL_SOURCE and TOOLCHAIN_EXTERNAL_SITE to empty, as part of a global cleanup to remove such assignments that supposedly had become unneeded following a fix of the package infrastructure (75630eba22b20d6140a5b58a6d1e35598fb3c0d3: core: do not attempt downloads with no _VERSION set). However, this causes TOOLCHAIN_EXTERNAL_SOURCE to be non-empty even for BR2_TOOLCHAIN_EXTERNAL_PREINSTALLED=y configuration, with the following consequences: - Buildroot downloads the toolchain tarball (while we're saying the toolchain is already available). Not dramatic, but clearly buggy. - Buildroot registers a post-extract hook that moves the toolchain from its extract directory (output/build/toolchain-external-.../ to its final location in host/opt/ext-toolchain/). Before doing this, it removes everything in TOOLCHAIN_EXTERNAL_INSTALL_DIR (which should normally be host/opt/ext-toolchain/). Another mistake that caused the bug is commit b731dc7bfb9c8ce7be502711f0b44ccab5515f1d ("toolchain-external: make extraction idempotent"), which introduce the dangerous call "rm -rf $(var)/*", which can be catastrophic if by mistake $(var) is empty. Instead, this commit should have just used rm -rf $(var) to remove the directory instead: it would have failed without consequences if $(var) is empty, and the directory was anyway already re-created right after with a mkdir. To address this problem, we: - Revert commit a0aa7e0e1750f6ace2879ea8adb1425a41431b79, so that _SOURCE and _SITE are empty in the pre-installed toolchain case. - Rework the code to ensure that similar problems will no happen in the future, by: - Registering the TOOLCHAIN_EXTERNAL_MOVE hook only when BR2_TOOLCHAIN_EXTERNAL_DOWNLOAD=y, since moving the toolchain is only needed when Buildroot downloaded the toolchain. - Introduce a variable TOOLCHAIN_EXTERNAL_DOWNLOAD_INSTALL_DIR which is the path in which Buildroot installs external toolchains when it is in charge of downloading/extracting them. Then, the TOOLCHAIN_EXTERNAL_MOVE hook is changed to use this variable, which is guaranteed to be non-empty. - Replace the removal of the directory contents $(var)/* by removing the directory itself $(var). The directory was anyway already re-created if needed afterwards. Thanks to doing this, if $(var) ever becomes empty, we will do "rm -rf" which will fail and abort the build, and not the catastrophic "rm -rf /*". Reported-by: Mason <slash.tmp@free.fr> Cc: Mason <slash.tmp@free.fr> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Signed-off-by: Peter Korsgaard <peter@korsgaard.com> (cherry picked from commit b171466c445dbdd39d5084dd4e4c138a7051d99a)
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