From: AKASHI Takahiro Date: Tue, 24 Sep 2013 09:00:50 +0000 (+0100) Subject: arm64: avoid multiple evaluation of ptr in get_user/put_user() X-Git-Tag: firefly_0821_release~3680^2~36^2~24^2~20 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=4d1e99cd1602a17035f53d6e420e4c18f4125a3b;p=firefly-linux-kernel-4.4.55.git arm64: avoid multiple evaluation of ptr in get_user/put_user() get_user() is defined as a function macro in arm64, and trace_get_user() calls it as followed: get_user(ch, ptr++); Since the second parameter occurs twice in the definition, 'ptr++' is unexpectedly evaluated twice and trace_get_user() will generate a bogus string from user-provided one. As a result, some ftrace sysfs operations, like "echo FUNCNAME > set_ftrace_filter," hit this case and eventually fail. This patch fixes the issue both in get_user() and put_user(). Signed-off-by: AKASHI Takahiro [catalin.marinas@arm.com: added __user type annotation and s/optr/__p/] Signed-off-by: Catalin Marinas (cherry picked from commit 1f65c13efef69b6dc908e588f91a133641d8475c) Signed-off-by: Mark Brown Conflicts: arch/arm64/include/asm/uaccess.h --- diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 8e8df0135f41..3bf8f4e99a51 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -167,9 +167,10 @@ do { \ #define get_user(x, ptr) \ ({ \ - might_sleep(); \ - access_ok(VERIFY_READ, (ptr), sizeof(*(ptr))) ? \ - __get_user((x), (ptr)) : \ + __typeof__(*(ptr)) __user *__p = (ptr); \ + might_fault(); \ + access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \ + __get_user((x), __p) : \ ((x) = 0, -EFAULT); \ }) @@ -228,9 +229,10 @@ do { \ #define put_user(x, ptr) \ ({ \ - might_sleep(); \ - access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ? \ - __put_user((x), (ptr)) : \ + __typeof__(*(ptr)) __user *__p = (ptr); \ + might_fault(); \ + access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ? \ + __put_user((x), __p) : \ -EFAULT; \ })