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author | Tobias Stoeckmann <tobias@stoeckmann.org> | 2019-07-12 19:43:59 +0200 |
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committer | Tobias Stoeckmann <tobias@stoeckmann.org> | 2019-07-12 19:43:59 +0200 |
commit | 2c38c9da3ea45d6c692314ad2e2f7213de2afaeb (patch) | |
tree | a48c15bc188c64836eb8c1f4e34fe6a2306a1182 /test/bg/exact/w/max | |
parent | 2c6e4fbabf502840a5138c489e3ace16294a9a75 (diff) |
Check stat for error before setting permissions.
When setting wallpapers without --no-fehbg option, a ~/.fehbg file is
created. This file is set to be an executable for later re-use.
Calling stat() without checking the return value can lead to issues.
If the call fails, then s.st_mode is undefined and excessive permissions
could be set to .fehbg, at worst even setuid/setgid bits for a world
writable file.
While adjusting this, I changed the code to use fstat() and fchmod() to
avoid a further -- but very unlikely -- issue: race condition in form of
TOCTOU. If the file ~/.fehsetbg is replaced by a symlink right before
the chmod call, then a different file would be set executable + the
default mode of the (newly created) file. I don't expect this to be a
real world issue but changed this part "while at it" anyway for more
robust code and a good example on how to handle files.
Signed-off-by: Tobias Stoeckmann <tobias@stoeckmann.org>
Diffstat (limited to 'test/bg/exact/w/max')
0 files changed, 0 insertions, 0 deletions