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

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: crypto: lib/mpi - avoid null pointer deref in mpi_cmp_ui() 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()

References

• https://git.kernel.org/stable/c/fde791e8a96a64ea7b0ad2440e43586447a209c6
• https://git.kernel.org/stable/c/ae63e84ffda74267bf7277c38415ba38389229a0
• https://git.kernel.org/stable/c/61f5453e9706e99713825594e0c8f9031485fb5f
• https://git.kernel.org/stable/c/0fc7147c694394f8a8cbc19570c6bc918cac0906
• https://git.kernel.org/stable/c/67589d247909043e94d2dd5fb590958e0f99d58d
• https://git.kernel.org/stable/c/d3ad023a39f1127dcfd331c562673355dc078650
• https://git.kernel.org/stable/c/12ac013ad7ff0df066451e825801d805095b3776
• https://git.kernel.org/stable/c/9e47a758b70167c9301d2b44d2569f86c7796f2d