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Merge ssh://master.kernel.org/home/hpa/tree/sec
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* ssh://master.kernel.org/home/hpa/tree/sec:
  x86-64, compat: Retruncate rax after ia32 syscall entry tracing
  x86-64, compat: Test %rax for the syscall number, not %eax
  compat: Make compat_alloc_user_space() incorporate the access_ok()
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Linus Torvalds committed Sep 15, 2010
2 parents a4128b0 + eefdca0 commit 9c03f16
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Showing 11 changed files with 46 additions and 16 deletions.
2 changes: 1 addition & 1 deletion arch/ia64/include/asm/compat.h
Original file line number Diff line number Diff line change
Expand Up @@ -199,7 +199,7 @@ ptr_to_compat(void __user *uptr)
}

static __inline__ void __user *
compat_alloc_user_space (long len)
arch_compat_alloc_user_space (long len)
{
struct pt_regs *regs = task_pt_regs(current);
return (void __user *) (((regs->r12 & 0xffffffff) & -16) - len);
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2 changes: 1 addition & 1 deletion arch/mips/include/asm/compat.h
Original file line number Diff line number Diff line change
Expand Up @@ -145,7 +145,7 @@ static inline compat_uptr_t ptr_to_compat(void __user *uptr)
return (u32)(unsigned long)uptr;
}

static inline void __user *compat_alloc_user_space(long len)
static inline void __user *arch_compat_alloc_user_space(long len)
{
struct pt_regs *regs = (struct pt_regs *)
((unsigned long) current_thread_info() + THREAD_SIZE - 32) - 1;
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2 changes: 1 addition & 1 deletion arch/parisc/include/asm/compat.h
Original file line number Diff line number Diff line change
Expand Up @@ -147,7 +147,7 @@ static inline compat_uptr_t ptr_to_compat(void __user *uptr)
return (u32)(unsigned long)uptr;
}

static __inline__ void __user *compat_alloc_user_space(long len)
static __inline__ void __user *arch_compat_alloc_user_space(long len)
{
struct pt_regs *regs = &current->thread.regs;
return (void __user *)regs->gr[30];
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2 changes: 1 addition & 1 deletion arch/powerpc/include/asm/compat.h
Original file line number Diff line number Diff line change
Expand Up @@ -134,7 +134,7 @@ static inline compat_uptr_t ptr_to_compat(void __user *uptr)
return (u32)(unsigned long)uptr;
}

static inline void __user *compat_alloc_user_space(long len)
static inline void __user *arch_compat_alloc_user_space(long len)
{
struct pt_regs *regs = current->thread.regs;
unsigned long usp = regs->gpr[1];
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2 changes: 1 addition & 1 deletion arch/s390/include/asm/compat.h
Original file line number Diff line number Diff line change
Expand Up @@ -181,7 +181,7 @@ static inline int is_compat_task(void)

#endif

static inline void __user *compat_alloc_user_space(long len)
static inline void __user *arch_compat_alloc_user_space(long len)
{
unsigned long stack;

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2 changes: 1 addition & 1 deletion arch/sparc/include/asm/compat.h
Original file line number Diff line number Diff line change
Expand Up @@ -167,7 +167,7 @@ static inline compat_uptr_t ptr_to_compat(void __user *uptr)
return (u32)(unsigned long)uptr;
}

static inline void __user *compat_alloc_user_space(long len)
static inline void __user *arch_compat_alloc_user_space(long len)
{
struct pt_regs *regs = current_thread_info()->kregs;
unsigned long usp = regs->u_regs[UREG_I6];
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2 changes: 1 addition & 1 deletion arch/tile/include/asm/compat.h
Original file line number Diff line number Diff line change
Expand Up @@ -195,7 +195,7 @@ static inline unsigned long ptr_to_compat_reg(void __user *uptr)
return (long)(int)(long __force)uptr;
}

static inline void __user *compat_alloc_user_space(long len)
static inline void __user *arch_compat_alloc_user_space(long len)
{
struct pt_regs *regs = task_pt_regs(current);
return (void __user *)regs->sp - len;
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22 changes: 14 additions & 8 deletions arch/x86/ia32/ia32entry.S
Original file line number Diff line number Diff line change
Expand Up @@ -50,7 +50,12 @@
/*
* Reload arg registers from stack in case ptrace changed them.
* We don't reload %eax because syscall_trace_enter() returned
* the value it wants us to use in the table lookup.
* the %rax value we should see. Instead, we just truncate that
* value to 32 bits again as we did on entry from user mode.
* If it's a new value set by user_regset during entry tracing,
* this matches the normal truncation of the user-mode value.
* If it's -1 to make us punt the syscall, then (u32)-1 is still
* an appropriately invalid value.
*/
.macro LOAD_ARGS32 offset, _r9=0
.if \_r9
Expand All @@ -60,6 +65,7 @@
movl \offset+48(%rsp),%edx
movl \offset+56(%rsp),%esi
movl \offset+64(%rsp),%edi
movl %eax,%eax /* zero extension */
.endm

.macro CFI_STARTPROC32 simple
Expand Down Expand Up @@ -153,7 +159,7 @@ ENTRY(ia32_sysenter_target)
testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%r10)
CFI_REMEMBER_STATE
jnz sysenter_tracesys
cmpl $(IA32_NR_syscalls-1),%eax
cmpq $(IA32_NR_syscalls-1),%rax
ja ia32_badsys
sysenter_do_call:
IA32_ARG_FIXUP
Expand Down Expand Up @@ -195,7 +201,7 @@ sysexit_from_sys_call:
movl $AUDIT_ARCH_I386,%edi /* 1st arg: audit arch */
call audit_syscall_entry
movl RAX-ARGOFFSET(%rsp),%eax /* reload syscall number */
cmpl $(IA32_NR_syscalls-1),%eax
cmpq $(IA32_NR_syscalls-1),%rax
ja ia32_badsys
movl %ebx,%edi /* reload 1st syscall arg */
movl RCX-ARGOFFSET(%rsp),%esi /* reload 2nd syscall arg */
Expand Down Expand Up @@ -248,7 +254,7 @@ sysenter_tracesys:
call syscall_trace_enter
LOAD_ARGS32 ARGOFFSET /* reload args from stack in case ptrace changed it */
RESTORE_REST
cmpl $(IA32_NR_syscalls-1),%eax
cmpq $(IA32_NR_syscalls-1),%rax
ja int_ret_from_sys_call /* sysenter_tracesys has set RAX(%rsp) */
jmp sysenter_do_call
CFI_ENDPROC
Expand Down Expand Up @@ -314,7 +320,7 @@ ENTRY(ia32_cstar_target)
testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%r10)
CFI_REMEMBER_STATE
jnz cstar_tracesys
cmpl $IA32_NR_syscalls-1,%eax
cmpq $IA32_NR_syscalls-1,%rax
ja ia32_badsys
cstar_do_call:
IA32_ARG_FIXUP 1
Expand Down Expand Up @@ -367,7 +373,7 @@ cstar_tracesys:
LOAD_ARGS32 ARGOFFSET, 1 /* reload args from stack in case ptrace changed it */
RESTORE_REST
xchgl %ebp,%r9d
cmpl $(IA32_NR_syscalls-1),%eax
cmpq $(IA32_NR_syscalls-1),%rax
ja int_ret_from_sys_call /* cstar_tracesys has set RAX(%rsp) */
jmp cstar_do_call
END(ia32_cstar_target)
Expand Down Expand Up @@ -425,7 +431,7 @@ ENTRY(ia32_syscall)
orl $TS_COMPAT,TI_status(%r10)
testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%r10)
jnz ia32_tracesys
cmpl $(IA32_NR_syscalls-1),%eax
cmpq $(IA32_NR_syscalls-1),%rax
ja ia32_badsys
ia32_do_call:
IA32_ARG_FIXUP
Expand All @@ -444,7 +450,7 @@ ia32_tracesys:
call syscall_trace_enter
LOAD_ARGS32 ARGOFFSET /* reload args from stack in case ptrace changed it */
RESTORE_REST
cmpl $(IA32_NR_syscalls-1),%eax
cmpq $(IA32_NR_syscalls-1),%rax
ja int_ret_from_sys_call /* ia32_tracesys has set RAX(%rsp) */
jmp ia32_do_call
END(ia32_syscall)
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2 changes: 1 addition & 1 deletion arch/x86/include/asm/compat.h
Original file line number Diff line number Diff line change
Expand Up @@ -205,7 +205,7 @@ static inline compat_uptr_t ptr_to_compat(void __user *uptr)
return (u32)(unsigned long)uptr;
}

static inline void __user *compat_alloc_user_space(long len)
static inline void __user *arch_compat_alloc_user_space(long len)
{
struct pt_regs *regs = task_pt_regs(current);
return (void __user *)regs->sp - len;
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3 changes: 3 additions & 0 deletions include/linux/compat.h
Original file line number Diff line number Diff line change
Expand Up @@ -360,5 +360,8 @@ extern ssize_t compat_rw_copy_check_uvector(int type,
const struct compat_iovec __user *uvector, unsigned long nr_segs,
unsigned long fast_segs, struct iovec *fast_pointer,
struct iovec **ret_pointer);

extern void __user *compat_alloc_user_space(unsigned long len);

#endif /* CONFIG_COMPAT */
#endif /* _LINUX_COMPAT_H */
21 changes: 21 additions & 0 deletions kernel/compat.c
Original file line number Diff line number Diff line change
Expand Up @@ -1126,3 +1126,24 @@ compat_sys_sysinfo(struct compat_sysinfo __user *info)

return 0;
}

/*
* Allocate user-space memory for the duration of a single system call,
* in order to marshall parameters inside a compat thunk.
*/
void __user *compat_alloc_user_space(unsigned long len)
{
void __user *ptr;

/* If len would occupy more than half of the entire compat space... */
if (unlikely(len > (((compat_uptr_t)~0) >> 1)))
return NULL;

ptr = arch_compat_alloc_user_space(len);

if (unlikely(!access_ok(VERIFY_WRITE, ptr, len)))
return NULL;

return ptr;
}
EXPORT_SYMBOL_GPL(compat_alloc_user_space);

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