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authorRobin Getz <robin.getz@analog.com>2009-06-04 00:32:59 +0000
committerMike Frysinger <vapier@gentoo.org>2009-06-12 06:12:02 -0400
commita8372b5ca618d4ea41b3c7ac3cef8dd6efa68bc6 (patch)
tree644ce05a655aef5082d614309afc4b6655a30a48 /arch/blackfin/include/asm/uaccess.h
parent685a694f0653b7db49f663b2cd6953695214fb30 (diff)
downloadlinux-2.6.38-lt-ux500-a8372b5ca618d4ea41b3c7ac3cef8dd6efa68bc6.tar.gz
Blackfin: add missing access_ok() checks to user functions
The core string/clear user functions weren't checking the user pointers which caused kernel crashes with some bad programs and tests (like LTP). Signed-off-by: Robin Getz <robin.getz@analog.com> Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Diffstat (limited to 'arch/blackfin/include/asm/uaccess.h')
-rw-r--r--arch/blackfin/include/asm/uaccess.h25
1 files changed, 20 insertions, 5 deletions
diff --git a/arch/blackfin/include/asm/uaccess.h b/arch/blackfin/include/asm/uaccess.h
index 3248033531e..97729be9894 100644
--- a/arch/blackfin/include/asm/uaccess.h
+++ b/arch/blackfin/include/asm/uaccess.h
@@ -233,16 +233,29 @@ strncpy_from_user(char *dst, const char *src, long count)
}
/*
- * Return the size of a string (including the ending 0)
+ * Get the size of a string in user space.
+ * src: The string to measure
+ * n: The maximum valid length
*
- * Return 0 on exception, a value greater than N if too long
+ * Get the size of a NUL-terminated string in user space.
+ *
+ * Returns the size of the string INCLUDING the terminating NUL.
+ * On exception, returns 0.
+ * If the string is too long, returns a value greater than n.
*/
-static inline long strnlen_user(const char *src, long n)
+static inline long __must_check strnlen_user(const char *src, long n)
{
- return (strlen(src) + 1);
+ if (!access_ok(VERIFY_READ, src, 1))
+ return 0;
+ return strnlen(src, n) + 1;
}
-#define strlen_user(str) strnlen_user(str, 32767)
+static inline long __must_check strlen_user(const char *src)
+{
+ if (!access_ok(VERIFY_READ, src, 1))
+ return 0;
+ return strlen(src) + 1;
+}
/*
* Zero Userspace
@@ -251,6 +264,8 @@ static inline long strnlen_user(const char *src, long n)
static inline unsigned long __must_check
__clear_user(void *to, unsigned long n)
{
+ if (!access_ok(VERIFY_WRITE, to, n))
+ return n;
memset(to, 0, n);
return 0;
}