Commit ae63e84f authored Aug 04, 2023 by Mark O'Donovan Committed by Greg Kroah-Hartman Sep 23, 2023

crypto: lib/mpi - avoid null pointer deref in mpi_cmp_ui()



[ Upstream commit 9e47a758b70167c9301d2b44d2569f86c7796f2d ]

During NVMeTCP Authentication a controller can trigger a kernel
oops by specifying the 8192 bit Diffie Hellman group and passing
a correctly sized, but zeroed Diffie Hellamn value.
mpi_cmp_ui() was detecting this if the second parameter was 0,
but 1 is passed from dh_is_pubkey_valid(). This causes the null
pointer u->d to be dereferenced towards the end of mpi_cmp_ui()

Signed-off-by: Mark O'Donovan <shiftee@posteo.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent 4dc0d161

lib/mpi/mpi-cmp.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -25,8 +25,12 @@ int mpi_cmp_ui(MPI u, unsigned long v)
		mpi_limb_t limb = v;

		mpi_normalize(u);
		if (!u->nlimbs && !limb)
		if (u->nlimbs == 0) {
		if (v == 0)
		return 0;
		else
		return -1;
		}
		if (u->sign)
		return -1;
		if (u->nlimbs > 1)