From: Mark O'Donovan shiftee@posteo.net
[ 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 --- lib/mpi/mpi-cmp.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/lib/mpi/mpi-cmp.c b/lib/mpi/mpi-cmp.c index d25e9e96c310f..ceaebe181cd70 100644 --- a/lib/mpi/mpi-cmp.c +++ b/lib/mpi/mpi-cmp.c @@ -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)