summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorArun Sharma <asharma@fb.com>2012-04-20 15:41:35 -0700
committerIngo Molnar <mingo@kernel.org>2012-06-06 17:08:01 +0200
commitbc6ca7b342d5ae15c3ba3081fd40271b8039fb25 (patch)
treec2fbb2f922b48a450df5b66c0dca13ba6fd51f98
parent0b0d9cf6ec7bab91977da2d71c09157f110f7c2e (diff)
perf/x86: Check if user fp is valid
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>
-rw-r--r--arch/x86/include/asm/uaccess.h12
-rw-r--r--arch/x86/kernel/cpu/perf_event.c12
2 files changed, 18 insertions, 6 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 04cd6882308e..e1f3a17034fc 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -33,9 +33,8 @@
#define segment_eq(a, b) ((a).seg == (b).seg)
#define user_addr_max() (current_thread_info()->addr_limit.seg)
-#define __addr_ok(addr) \
- ((unsigned long __force)(addr) < \
- (current_thread_info()->addr_limit.seg))
+#define __addr_ok(addr) \
+ ((unsigned long __force)(addr) < user_addr_max())
/*
* 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...
*/
-#define __range_not_ok(addr, size) \
+#define __range_not_ok(addr, size, limit) \
({ \
unsigned long flag, roksum; \
__chk_user_ptr(addr); \
asm("add %3,%1 ; sbb %0,%0 ; cmp %1,%4 ; sbb $0,%0" \
: "=&r" (flag), "=r" (roksum) \
: "1" (addr), "g" ((long)(size)), \
- "rm" (current_thread_info()->addr_limit.seg)); \
+ "rm" (limit)); \
flag; \
})
@@ -77,7 +76,8 @@
* checks that the pointer is in the user space range - after calling
* 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
diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
index e78bc256aea8..c4706cf9c011 100644
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -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);
}
+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
#include <asm/compat.h>
@@ -1781,6 +1787,9 @@ perf_callchain_user32(struct pt_regs *regs, struct perf_callchain_entry *entry)
if (bytes != sizeof(frame))
break;
+ if (!valid_user_frame(fp, sizeof(frame)))
+ break;
+
perf_callchain_store(entry, frame.return_address);
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))
break;
+ if (!valid_user_frame(fp, sizeof(frame)))
+ break;
+
perf_callchain_store(entry, frame.return_address);
fp = frame.next_frame;
}