crypto: testmgr - add guard to dst buffer for ahash_export (7bcb87bc) · Commits · 戴 / test

Add a guard to 'state' buffer and warn if its consistency after call to crypto_ahash_export() changes, so that any write that goes beyond advertised statesize (and thus causing potential memory corruption [1]) is more visible. [1] https://marc.info/?l=linux-crypto-vger&m=147467656516085 Signed-off-by:

Jan Stancek <jstancek@redhat.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Marcelo Cerri <marcelo.cerri@canonical.com> Signed-off-by:

Herbert Xu <herbert@gondor.apana.org.au>

crypto/testmgr.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -209,16 +209,19 @@ static int ahash_partial_update(struct ahash_request **preq,
		char *state;
		struct ahash_request *req;
		int statesize, ret = -EINVAL;
		const char guard[] = { 0x00, 0xba, 0xad, 0x00 };

		req = *preq;
		statesize = crypto_ahash_statesize(
		crypto_ahash_reqtfm(req));
		state = kmalloc(statesize, GFP_KERNEL);
		state = kmalloc(statesize + sizeof(guard), GFP_KERNEL);
		if (!state) {
		pr_err("alt: hash: Failed to alloc state for %s\n", algo);
		goto out_nostate;
		}
		memcpy(state + statesize, guard, sizeof(guard));
		ret = crypto_ahash_export(req, state);
		WARN_ON(memcmp(state + statesize, guard, sizeof(guard)));
		if (ret) {
		pr_err("alt: hash: Failed to export() for %s\n", algo);
		goto out;

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