stefanberger
commented
1 year ago This particular patch has now been merged upstream: https://github.com/torvalds/linux/commit/c3d03e8e35e005e1a614e51bb59053eeb5857f76
I need this patch for proper EVM signature enforcement and will drop it from my OpenBMC series of patches once the OpenBMC Linux build includes this patch. I have been carrying this patch here lately: https://gerrit.openbmc.org/c/openbmc/openbmc/+/63909
Commit ac4e97abce9b8 ("scatterlist: sg_set_buf() argument must be in linear mapping") checks that both the signature and the digest reside in the linear mapping area.
However, more recently commit ba14a194a434c ("fork: Add generic vmalloced stack support") made it possible to move the stack in the vmalloc area, which is not contiguous, and thus not suitable for sg_set_buf() which needs adjacent pages.
Always make a copy of the signature and digest in the same buffer used to store the key and its parameters, and pass them to sg_init_one(). Prefer it to conditionally doing the copy if necessary, to keep the code simple. The buffer allocated with kmalloc() is in the linear mapping area.
Cc: stable@vger.kernel.org # 4.9.x Fixes: ba14a194a434 ("fork: Add generic vmalloced stack support") Link: https://lore.kernel.org/linux-integrity/Y4pIpxbjBdajymBJ@sol.localdomain/ Suggested-by: Eric Biggers ebiggers@kernel.org
Reviewed-by: Eric Biggers ebiggers@google.com Tested-by: Stefan Berger stefanb@linux.ibm.com