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;
