This is a note to let you know that I've just added the patch titled x86/fpu: Limit xstate copy size in xstateregs_set() to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: x86-fpu-limit-xstate-copy-size-in-xstateregs_set.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit ddf66f3563eb904c19bf434515cd17dea6663021 Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Date: Wed Jun 23 14:01:35 2021 +0200 x86/fpu: Limit xstate copy size in xstateregs_set() [ Upstream commit 07d6688b22e09be465652cf2da0da6bf86154df6 ] If the count argument is larger than the xstate size, this will happily copy beyond the end of xstate. Fixes: 91c3dba7dbc1 ("x86/fpu/xstate: Fix PTRACE frames for XSAVES") Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Signed-off-by: Borislav Petkov <bp@xxxxxxx> Reviewed-by: Andy Lutomirski <luto@xxxxxxxxxx> Reviewed-by: Borislav Petkov <bp@xxxxxxx> Link: https://lkml.kernel.org/r/20210623121452.120741557@xxxxxxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c index d652b939ccfb..68e1fb66e701 100644 --- a/arch/x86/kernel/fpu/regset.c +++ b/arch/x86/kernel/fpu/regset.c @@ -124,7 +124,7 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset, /* * A whole standard-format XSAVE buffer is needed: */ - if ((pos != 0) || (count < fpu_user_xstate_size)) + if (pos != 0 || count != fpu_user_xstate_size) return -EFAULT; xsave = &fpu->state.xsave;