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

[ Upstream commit 9e47a758b7 ]

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>
This commit is contained in:
Mark O'Donovan 2023-08-04 09:32:18 +00:00 committed by Greg Kroah-Hartman
parent e5d94c98a7
commit d3ad023a39
1 changed files with 6 additions and 2 deletions

View File

@ -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)
return 0;
if (u->nlimbs == 0) {
if (v == 0)
return 0;
else
return -1;
}
if (u->sign)
return -1;
if (u->nlimbs > 1)