sparc64: perf: Add sanity checking on addresses in user stack
Processes are getting killed (sigbus or segv) while walking userspace
callchains when using perf. In some instances I have seen ufp = 0x7ff
which does not seem like a proper stack address.
This patch adds a function to run validity checks against the address
before attempting the copy_from_user. The checks are copied from the
x86 version as a start point with the addition of a 4-byte alignment
check.
Signed-off-by: David Ahern <david.ahern@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/arch/sparc/include/asm/uaccess_64.h b/arch/sparc/include/asm/uaccess_64.h
index a35194b..ea6e9a2 100644
--- a/arch/sparc/include/asm/uaccess_64.h
+++ b/arch/sparc/include/asm/uaccess_64.h
@@ -49,6 +49,28 @@
__asm__ __volatile__ ("wr %%g0, %0, %%asi" : : "r" ((val).seg)); \
} while(0)
+/*
+ * Test whether a block of memory is a valid user space address.
+ * Returns 0 if the range is valid, nonzero otherwise.
+ */
+static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, unsigned long limit)
+{
+ if (__builtin_constant_p(size))
+ return addr > limit - size;
+
+ addr += size;
+ if (addr < size)
+ return true;
+
+ return addr > limit;
+}
+
+#define __range_not_ok(addr, size, limit) \
+({ \
+ __chk_user_ptr(addr); \
+ __chk_range_not_ok((unsigned long __force)(addr), size, limit); \
+})
+
static inline int __access_ok(const void __user * addr, unsigned long size)
{
return 1;
diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c
index 48387be..a665e3f 100644
--- a/arch/sparc/kernel/perf_event.c
+++ b/arch/sparc/kernel/perf_event.c
@@ -1741,6 +1741,16 @@
} while (entry->nr < PERF_MAX_STACK_DEPTH);
}
+static inline int
+valid_user_frame(const void __user *fp, unsigned long size)
+{
+ /* addresses should be at least 4-byte aligned */
+ if (((unsigned long) fp) & 3)
+ return 0;
+
+ return (__range_not_ok(fp, size, TASK_SIZE) == 0);
+}
+
static void perf_callchain_user_64(struct perf_callchain_entry *entry,
struct pt_regs *regs)
{
@@ -1753,6 +1763,9 @@
unsigned long pc;
usf = (struct sparc_stackf __user *)ufp;
+ if (!valid_user_frame(usf, sizeof(sf)))
+ break;
+
if (__copy_from_user_inatomic(&sf, usf, sizeof(sf)))
break;