| Message ID | 524154C2.1080303@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, Sep 24, 2013 at 10:00:50AM +0100, AKASHI Takahiro wrote: > 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 <takahiro.akashi@linaro.org> > --- > arch/arm64/include/asm/uaccess.h | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h > index edb3d5c..bbeab83 100644 > --- a/arch/arm64/include/asm/uaccess.h > +++ b/arch/arm64/include/asm/uaccess.h > @@ -166,9 +166,11 @@ do { \ > #define get_user(x, ptr) \ > ({ \ > + __typeof__(*(ptr)) *optr = (ptr); \ I think this should be: __typeof__(*(ptr)) __user *optr = (ptr); Otherwise the patch looks fine. I can fix the above. Thanks.
On Tue, Sep 24, 2013 at 10:00:50AM +0100, AKASHI Takahiro wrote: > 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 <takahiro.akashi@linaro.org> > --- > arch/arm64/include/asm/uaccess.h | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h > index edb3d5c..bbeab83 100644 > --- a/arch/arm64/include/asm/uaccess.h > +++ b/arch/arm64/include/asm/uaccess.h > @@ -166,9 +166,11 @@ do { \ > #define get_user(x, ptr) \ > ({ \ > + __typeof__(*(ptr)) *optr = (ptr); \ > + \ > might_fault(); \ > - access_ok(VERIFY_READ, (ptr), sizeof(*(ptr))) ? \ > - __get_user((x), (ptr)) : \ > + access_ok(VERIFY_READ, optr, sizeof(*optr)) ? \ > + __get_user((x), optr) : \ > ((x) = 0, -EFAULT); \ > }) > @@ -227,9 +229,11 @@ do { \ > #define put_user(x, ptr) \ > ({ \ > + __typeof__(*(ptr)) *optr = (ptr); \ > + \ > might_fault(); \ > - access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ? \ > - __put_user((x), (ptr)) : \ > + access_ok(VERIFY_WRITE, optr, sizeof(*optr)) ? \ > + __put_user((x), optr) : \ > -EFAULT; \ > }) > -- 1.7.9.5 BTW, please use git send-email or other email client, the diff above is heavily corrupted (too many spaces at the beginning of the line, removed empty lines; I managed to fix it up this time but only because it was a small patch).
Catalin, Thank you for your comments, and let me send a revised patch again because my original message didn't reach MLs due to my screw-up. BTW, I will submit a patch of ftrace support on arm64 once gcc supports gprof (-pg) options. -Takahiro AKASHI On 09/24/2013 11:25 PM, Catalin Marinas wrote: > On Tue, Sep 24, 2013 at 10:00:50AM +0100, AKASHI Takahiro wrote: >> 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 <takahiro.akashi@linaro.org> >> --- >> arch/arm64/include/asm/uaccess.h | 12 ++++++++---- >> 1 file changed, 8 insertions(+), 4 deletions(-) >> >> diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h >> index edb3d5c..bbeab83 100644 >> --- a/arch/arm64/include/asm/uaccess.h >> +++ b/arch/arm64/include/asm/uaccess.h >> @@ -166,9 +166,11 @@ do { \ >> #define get_user(x, ptr) \ >> ({ \ >> + __typeof__(*(ptr)) *optr = (ptr); \ >> + \ >> might_fault(); \ >> - access_ok(VERIFY_READ, (ptr), sizeof(*(ptr))) ? \ >> - __get_user((x), (ptr)) : \ >> + access_ok(VERIFY_READ, optr, sizeof(*optr)) ? \ >> + __get_user((x), optr) : \ >> ((x) = 0, -EFAULT); \ >> }) >> @@ -227,9 +229,11 @@ do { \ >> #define put_user(x, ptr) \ >> ({ \ >> + __typeof__(*(ptr)) *optr = (ptr); \ >> + \ >> might_fault(); \ >> - access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ? \ >> - __put_user((x), (ptr)) : \ >> + access_ok(VERIFY_WRITE, optr, sizeof(*optr)) ? \ >> + __put_user((x), optr) : \ >> -EFAULT; \ >> }) >> -- 1.7.9.5 > > BTW, please use git send-email or other email client, the diff above is > heavily corrupted (too many spaces at the beginning of the line, removed > empty lines; I managed to fix it up this time but only because it was a > small patch). >
On Wed, Sep 25, 2013 at 10:29:52AM +0100, AKASHI Takahiro wrote: > Thank you for your comments, and let me send a revised patch again > because my original message didn't reach MLs due to my screw-up. You can send it if you want but I already merged it in my tree (should appear in -next this week as well).
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index edb3d5c..bbeab83 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -166,9 +166,11 @@ do { \ #define get_user(x, ptr) \ ({ \ + __typeof__(*(ptr)) *optr = (ptr); \ + \ might_fault(); \ - access_ok(VERIFY_READ, (ptr), sizeof(*(ptr))) ? \ - __get_user((x), (ptr)) : \ + access_ok(VERIFY_READ, optr, sizeof(*optr)) ? \ + __get_user((x), optr) : \ ((x) = 0, -EFAULT); \ }) @@ -227,9 +229,11 @@ do { \ #define put_user(x, ptr) \
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 <takahiro.akashi@linaro.org> --- arch/arm64/include/asm/uaccess.h | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) ({ \ + __typeof__(*(ptr)) *optr = (ptr); \ + \ might_fault(); \ - access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ? \ - __put_user((x), (ptr)) : \ + access_ok(VERIFY_WRITE, optr, sizeof(*optr)) ? \ + __put_user((x), optr) : \ -EFAULT; \ }) -- 1.7.9.5