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Commit 656de42e authored by Kees Cook's avatar Kees Cook
Browse files

pstore: Avoid potential infinite loop 



If a backend does not correctly iterate through its records, pstore will
get stuck loading entries. Detect this with a large record count, and
announce if we ever hit the limit. This will let future backend reading
bugs less annoying to debug. Additionally adjust the error about
pstore_mkfile() failing.

Signed-off-by: default avatarKees Cook <keescook@chromium.org>
parent f6525b96

fs/pstore/platform.c

+6 −2
Original line number Diff line number Diff line
@@ -822,6 +822,7 @@ void pstore_get_backend_records(struct pstore_info *psi, 
				struct dentry *root, int quiet)

{

	int failed = 0;

	unsigned int stop_loop = 65536;



	if (!psi || !root)

		return;
@@ -835,7 +836,7 @@ void pstore_get_backend_records(struct pstore_info *psi, 
	 * may reallocate record.buf. On success, pstore_mkfile() will keep

	 * the record.buf, so free it only on failure.

	 */

	for (;;) {

	for (; stop_loop; stop_loop--) {

		struct pstore_record *record;

		int rc;
@@ -870,8 +871,11 @@ void pstore_get_backend_records(struct pstore_info *psi, 
	mutex_unlock(&psi->read_mutex);



	if (failed)

		pr_warn("failed to load %d record(s) from '%s'\n",

		pr_warn("failed to create %d record(s) from '%s'\n",

			failed, psi->name);

	if (!stop_loop)

		pr_err("looping? Too many records seen from '%s'\n",

			psi->name);

}



static void pstore_dowork(struct work_struct *work)