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authorAndy Lutomirski <luto@kernel.org>2016-05-10 18:18:46 +0200
committerIngo Molnar <mingo@kernel.org>2016-05-20 09:10:03 +0200
commitd696ca016d579d43fc043f28ba656d9305fba651 (patch)
tree8ad4ce52e4aaa359b08784126b66f6ea2190b834 /arch/x86
parentMerge branch 'linus' into x86/urgent, to refresh the tree (diff)
downloadlinux-d696ca016d579d43fc043f28ba656d9305fba651.tar.xz
linux-d696ca016d579d43fc043f28ba656d9305fba651.zip
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: Andy 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.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/kernel/process_64.c4
-rw-r--r--arch/x86/kernel/ptrace.c4
2 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 6b16c36f0939..6e789ca1f841 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -532,7 +532,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
switch (code) {
case ARCH_SET_GS:
- if (addr >= TASK_SIZE_OF(task))
+ if (addr >= TASK_SIZE_MAX)
return -EPERM;
cpu = get_cpu();
task->thread.gsindex = 0;
@@ -546,7 +546,7 @@ long do_arch_prctl(struct task_struct *task, int code, unsigned long addr)
case ARCH_SET_FS:
/* Not strictly needed for fs, but do it for symmetry
with gs */
- if (addr >= TASK_SIZE_OF(task))
+ if (addr >= TASK_SIZE_MAX)
return -EPERM;
cpu = get_cpu();
task->thread.fsindex = 0;
diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c
index e60ef918f53d..600edd225e81 100644
--- a/arch/x86/kernel/ptrace.c
+++ b/arch/x86/kernel/ptrace.c
@@ -392,7 +392,7 @@ static int putreg(struct task_struct *child,
#ifdef CONFIG_X86_64
case offsetof(struct user_regs_struct,fs_base):
- if (value >= TASK_SIZE_OF(child))
+ if (value >= TASK_SIZE_MAX)
return -EIO;
/*
* When changing the segment base, use do_arch_prctl
@@ -406,7 +406,7 @@ static int putreg(struct task_struct *child,
/*
* Exactly the same here as the %fs handling above.
*/
- if (value >= TASK_SIZE_OF(child))
+ if (value >= TASK_SIZE_MAX)
return -EIO;
if (child->thread.gsbase != value)
return do_arch_prctl(child, ARCH_SET_GS, value);