From 990e9dc381e6999a0eba8ebaf8747daaa8c58337 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Sat, 10 Dec 2016 00:13:51 +0100 Subject: [PATCH] x86/ldt: Make all size computations unsigned ldt->size can never be negative. The helper functions take 'unsigned int' arguments which are assigned from ldt->size. The related user space user_desc struct member entry_number is unsigned as well. But ldt->size itself and a few local variables which are related to ldt->size are type 'int' which makes no sense whatsoever and results in typecasts which make the eyes bleed. Clean it up and convert everything which is related to ldt->size to unsigned it. Signed-off-by: Thomas Gleixner Cc: Andy Lutomirski Cc: Dave Hansen Cc: Andrey Ryabinin Cc: Dan Carpenter --- arch/x86/events/core.c | 2 +- arch/x86/include/asm/mmu_context.h | 2 +- arch/x86/kernel/ldt.c | 10 +++++----- 3 files changed, 7 insertions(+), 7 deletions(-) diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index 6e395c996900..55e6c8a397c2 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -2299,7 +2299,7 @@ valid_user_frame(const void __user *fp, unsigned long size) static unsigned long get_segment_base(unsigned int segment) { struct desc_struct *desc; - int idx = segment >> 3; + unsigned int idx = segment >> 3; if ((segment & SEGMENT_TI_MASK) == SEGMENT_LDT) { #ifdef CONFIG_MODIFY_LDT_SYSCALL diff --git a/arch/x86/include/asm/mmu_context.h b/arch/x86/include/asm/mmu_context.h index 8e0a9fe86de4..306c7e12af55 100644 --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -47,7 +47,7 @@ struct ldt_struct { * allocations, but it's not worth trying to optimize. */ struct desc_struct *entries; - int size; + unsigned int size; }; /* diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c index e25b6681cc65..f09df2ff1bcc 100644 --- a/arch/x86/kernel/ldt.c +++ b/arch/x86/kernel/ldt.c @@ -37,7 +37,7 @@ static void flush_ldt(void *current_mm) static struct ldt_struct *alloc_ldt_struct(unsigned int size) { struct ldt_struct *new_ldt; - int alloc_size; + unsigned int alloc_size; if (size > LDT_ENTRIES) return NULL; @@ -207,11 +207,11 @@ static int read_default_ldt(void __user *ptr, unsigned long bytecount) static int write_ldt(void __user *ptr, unsigned long bytecount, int oldmode) { struct mm_struct *mm = current->mm; + struct ldt_struct *new_ldt, *old_ldt; + unsigned int oldsize, newsize; + struct user_desc ldt_info; struct desc_struct ldt; int error; - struct user_desc ldt_info; - int oldsize, newsize; - struct ldt_struct *new_ldt, *old_ldt; error = -EINVAL; if (bytecount != sizeof(ldt_info)) @@ -249,7 +249,7 @@ static int write_ldt(void __user *ptr, unsigned long bytecount, int oldmode) old_ldt = mm->context.ldt; oldsize = old_ldt ? old_ldt->size : 0; - newsize = max((int)(ldt_info.entry_number + 1), oldsize); + newsize = max(ldt_info.entry_number + 1, oldsize); error = -ENOMEM; new_ldt = alloc_ldt_struct(newsize); -- 2.20.1