Commit-ID: 603e492e861861ddfec7139a007abad74f0d3af0
Gitweb: http://git.kernel.org/tip/603e492e861861ddfec7139a007abad74f0d3af0
Author: Andy Lutomirski <luto@xxxxxxxxxx>
AuthorDate: Wed, 9 Aug 2017 14:39:45 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Thu, 10 Aug 2017 13:14:58 +0200
x86/asm/32: Fix regs_get_register() on segment registers
The segment register high words on x86_32 may contain garbage.
Teach regs_get_register() to read them as u16 instead of unsigned
long.
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/0b76f6dbe477b7b1a81938fddcc3c483d48f0ff2.1502314765.git.luto@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/x86/include/asm/ptrace.h | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h
index a29f828..91c04c8 100644
--- a/arch/x86/include/asm/ptrace.h
+++ b/arch/x86/include/asm/ptrace.h
@@ -196,6 +196,17 @@ static inline unsigned long regs_get_register(struct pt_regs *regs,
if (offset == offsetof(struct pt_regs, sp) &&
regs->cs == __KERNEL_CS)
return kernel_stack_pointer(regs);
+
+ /* The selector fields are 16-bit. */
+ if (offset == offsetof(struct pt_regs, cs) ||
+ offset == offsetof(struct pt_regs, ss) ||
+ offset == offsetof(struct pt_regs, ds) ||
+ offset == offsetof(struct pt_regs, es) ||
+ offset == offsetof(struct pt_regs, fs) ||
+ offset == offsetof(struct pt_regs, gs)) {
+ return *(u16 *)((unsigned long)regs + offset);
+
+ }
#endif
return *(unsigned long *)((unsigned long)regs + offset);
}
--
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