Commit d696ca01 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Ingo Molnar

x86/fsgsbase/64: Use TASK_SIZE_MAX for FSBASE/GSBASE upper limits

The GSBASE upper limit exists to prevent user code from confusing
the paranoid idtentry path.  The FSBASE upper limit is just for
consistency.  There's no need to enforce a smaller limit for 32-bit
tasks.

Just use TASK_SIZE_MAX.  This simplifies the logic and will save a
few bytes of code.
Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/5357f2fe0f103eabf005773b70722451eab09a89.1462897104.git.luto@kernel.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 06cd3d8c
...@@ -532,7 +532,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr) ...@@ -532,7 +532,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
switch (code) { switch (code) {
case ARCH_SET_GS: case ARCH_SET_GS:
if (addr >= TASK_SIZE_OF(task)) if (addr >= TASK_SIZE_MAX)
return -EPERM; return -EPERM;
cpu = get_cpu(); cpu = get_cpu();
task->thread.gsindex = 0; task->thread.gsindex = 0;
...@@ -546,7 +546,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr) ...@@ -546,7 +546,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
case ARCH_SET_FS: case ARCH_SET_FS:
/* Not strictly needed for fs, but do it for symmetry /* Not strictly needed for fs, but do it for symmetry
with gs */ with gs */
if (addr >= TASK_SIZE_OF(task)) if (addr >= TASK_SIZE_MAX)
return -EPERM; return -EPERM;
cpu = get_cpu(); cpu = get_cpu();
task->thread.fsindex = 0; task->thread.fsindex = 0;
......
...@@ -392,7 +392,7 @@ static int putreg(struct task_struct *child, ...@@ -392,7 +392,7 @@ static int putreg(struct task_struct *child,
#ifdef CONFIG_X86_64 #ifdef CONFIG_X86_64
case offsetof(struct user_regs_struct,fs_base): case offsetof(struct user_regs_struct,fs_base):
if (value >= TASK_SIZE_OF(child)) if (value >= TASK_SIZE_MAX)
return -EIO; return -EIO;
/* /*
* When changing the segment base, use do_arch_prctl * When changing the segment base, use do_arch_prctl
...@@ -406,7 +406,7 @@ static int putreg(struct task_struct *child, ...@@ -406,7 +406,7 @@ static int putreg(struct task_struct *child,
/* /*
* Exactly the same here as the %fs handling above. * Exactly the same here as the %fs handling above.
*/ */
if (value >= TASK_SIZE_OF(child)) if (value >= TASK_SIZE_MAX)
return -EIO; return -EIO;
if (child->thread.gsbase != value) if (child->thread.gsbase != value)
return do_arch_prctl(child, ARCH_SET_GS, value); return do_arch_prctl(child, ARCH_SET_GS, value);
......
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