fix stack overflow in ExpandLinks path component parsing#6209
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Signed-off-by: Aizal Khan <aizumusheer2@gmail.com>
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Thanks for submitting a pull request! Maybe @larsewi can review this? |
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Co-authored-by: Lars Erik Wik <53906608+larsewi@users.noreply.github.com>
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@cf-bottom Jenkins please :) |
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Sure, I triggered a build: Jenkins: https://ci.cfengine.com/job/pr-pipeline/14180/ Packages: http://buildcache.cfengine.com/packages/testing-pr/jenkins-pr-pipeline-14180/ |
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Please squash the two commits and rebase :) |
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Found this reading the symlink resolver.
ExpandLinks() splits the path one component at a time with sscanf(sp, "%[^/]", node) into node[CF_MAXLINKSIZE] (256), no field width.
the parse runs before the lstat(), and the recursive call hands readlink() targets (up to CF_BUFSIZE-1) back in as
from, so a symlink target that is a single long slash-free component overruns the stack.Measured the component with strcspn() first and bail the same way the rest of the function already does on an over-long path. Regression test added under tests/unit.