Commit 24d68345 authored by Mark Brown's avatar Mark Brown Committed by Catalin Marinas
Browse files

arm64/signal: Only read new data when parsing the ZA context 



When we parse the ZA signal context we read the entire context from
userspace, including the generic signal context header which was already
read by parse_user_sigframe() and padding bytes that we ignore. Avoid the
possibility of relying on the second read of the data read twice by only
reading the data which we are actually going to use.

Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20221212-arm64-signal-cleanup-v3-6-4545c94b20ff@kernel.org


Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent f3ac48aa

arch/arm64/kernel/signal.c

+7 −6
Original line number Diff line number Diff line
@@ -435,17 +435,18 @@ static int preserve_za_context(struct za_context __user *ctx) 


static int restore_za_context(struct user_ctxs *user)

{

	int err;

	int err = 0;

	unsigned int vq;

	struct za_context za;

	u16 user_vl;



	if (user->za_size < sizeof(*user->za))

		return -EINVAL;



	if (__copy_from_user(&za, user->za, sizeof(za)))

		return -EFAULT;

	__get_user_error(user_vl, &(user->za->vl), err);

	if (err)

		return err;



	if (za.vl != task_get_sme_vl(current))

	if (user_vl != task_get_sme_vl(current))

		return -EINVAL;



	if (user->za_size == sizeof(*user->za)) {
@@ -453,7 +454,7 @@ static int restore_za_context(struct user_ctxs *user) 
		return 0;

	}



	vq = sve_vq_from_vl(za.vl);

	vq = sve_vq_from_vl(user_vl);



	if (user->za_size < ZA_SIG_CONTEXT_SIZE(vq))

		return -EINVAL;