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perf/x86: Check if user fp is valid

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Signed-off-by: Arun Sharma <asharma@fb.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1334961696-19580-4-git-send-email-asharma@fb.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Arun Sharma 2012-04-20 15:41:35 -07:00 committed by Ingo Molnar
parent 0b0d9cf6ec
commit bc6ca7b342
2 changed files with 18 additions and 6 deletions
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12
arch/x86/include/asm/uaccess.h
View File

@ -33,9 +33,8 @@
#define segment_eq(a, b) ((a).seg == (b).seg) #define segment_eq(a, b) ((a).seg == (b).seg)
#define user_addr_max() (current_thread_info()->addr_limit.seg) #define user_addr_max() (current_thread_info()->addr_limit.seg)
#define __addr_ok(addr) \ #define __addr_ok(addr) \
((unsigned long __force)(addr) < \ ((unsigned long __force)(addr) < user_addr_max())
(current_thread_info()->addr_limit.seg))
/* /*
* Test whether a block of memory is a valid user space address. * Test whether a block of memory is a valid user space address.
@ -47,14 +46,14 @@
* This needs 33-bit (65-bit for x86_64) arithmetic. We have a carry... * This needs 33-bit (65-bit for x86_64) arithmetic. We have a carry...
*/ */
#define __range_not_ok(addr, size) \ #define __range_not_ok(addr, size, limit) \
({ \ ({ \
unsigned long flag, roksum; \ unsigned long flag, roksum; \
__chk_user_ptr(addr); \ __chk_user_ptr(addr); \
asm("add %3,%1 ; sbb %0,%0 ; cmp %1,%4 ; sbb $0,%0" \ asm("add %3,%1 ; sbb %0,%0 ; cmp %1,%4 ; sbb $0,%0" \
: "=&r" (flag), "=r" (roksum) \ : "=&r" (flag), "=r" (roksum) \
: "1" (addr), "g" ((long)(size)), \ : "1" (addr), "g" ((long)(size)), \
"rm" (current_thread_info()->addr_limit.seg)); \ "rm" (limit)); \
flag; \ flag; \
}) })
@ -77,7 +76,8 @@
* checks that the pointer is in the user space range - after calling * checks that the pointer is in the user space range - after calling
* this function, memory access functions may still return -EFAULT. * this function, memory access functions may still return -EFAULT.
*/ */
#define access_ok(type, addr, size) (likely(__range_not_ok(addr, size) == 0)) #define access_ok(type, addr, size) \
(likely(__range_not_ok(addr, size, user_addr_max()) == 0))
/* /*
* The exception table consists of pairs of addresses relative to the * The exception table consists of pairs of addresses relative to the

12
arch/x86/kernel/cpu/perf_event.c
View File

@ -1757,6 +1757,12 @@ perf_callchain_kernel(struct perf_callchain_entry *entry, struct pt_regs *regs)
dump_trace(NULL, regs, NULL, 0, &backtrace_ops, entry); dump_trace(NULL, regs, NULL, 0, &backtrace_ops, entry);
} }
static inline int
valid_user_frame(const void __user *fp, unsigned long size)
{
return (__range_not_ok(fp, size, TASK_SIZE) == 0);
}
#ifdef CONFIG_COMPAT #ifdef CONFIG_COMPAT
#include <asm/compat.h> #include <asm/compat.h>
@ -1781,6 +1787,9 @@ perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry *entry)
if (bytes != sizeof(frame)) if (bytes != sizeof(frame))
break; break;
if (!valid_user_frame(fp, sizeof(frame)))
break;
perf_callchain_store(entry, frame.return_address); perf_callchain_store(entry, frame.return_address);
fp = compat_ptr(frame.next_frame); fp = compat_ptr(frame.next_frame);
} }
@ -1824,6 +1833,9 @@ perf_callchain_user(struct perf_callchain_entry *entry, struct pt_regs *regs)
if (bytes != sizeof(frame)) if (bytes != sizeof(frame))
break; break;
if (!valid_user_frame(fp, sizeof(frame)))
break;
perf_callchain_store(entry, frame.return_address); perf_callchain_store(entry, frame.return_address);
fp = frame.next_frame; fp = frame.next_frame;
} }