pstore: Protect unlink with read_mutex
When update_ms is set, pstore_get_records() will be called when there's a new entry. But unlink can be called at the same time and might contend with the open-read-close loop. Depending on the implementation of platform driver, it may be safe or not. But I think it'd be better to protect those race in the first place. Cc: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Namhyung Kim <namhyung@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org>
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@ -199,11 +199,14 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
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if (err)
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if (err)
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return err;
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return err;
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if (p->psi->erase)
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if (p->psi->erase) {
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mutex_lock(&p->psi->read_mutex);
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p->psi->erase(p->type, p->id, p->count,
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p->psi->erase(p->type, p->id, p->count,
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d_inode(dentry)->i_ctime, p->psi);
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d_inode(dentry)->i_ctime, p->psi);
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else
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mutex_unlock(&p->psi->read_mutex);
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} else {
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return -EPERM;
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return -EPERM;
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}
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return simple_unlink(dir, dentry);
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return simple_unlink(dir, dentry);
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}
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}
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