Re: [PATCH 2/5] trace-cmd: Fix NULL pointer being passed to memcpy
On Mon, 9 Oct 2017 16:27:10 -0600 Michael Sartain wrote: > > > - memcpy(option->data, data, size); > > > + > > > + /* Some IDs (like TRACECMD_OPTION_TRACECLOCK) pass NULL data */ > > > + if (data) > > > + memcpy(option->data, data, size); > > > > Is this a problem, as when this happens, size should be zero. Does it > > crash with data=NULL and size=0, or have you seen size not be zero? > > I got an ASAN warning, but you are correct - the size was 0 and it did > not crash. OK, but it's almost like dividing zero from zero. Can you send another patch, but this time check if (size) instead of if (data). -- Steve
Re: [PATCH 2/5] trace-cmd: Fix NULL pointer being passed to memcpy
On Mon, Oct 09, 2017 at 06:24:32PM -0400, Steven Rostedt wrote: > On Sat, 12 Aug 2017 11:30:44 -0600 > Michael Sartain wrote: > > > Signed-off-by: Michael Sartain > > --- > > trace-output.c | 6 +- > > 1 file changed, 5 insertions(+), 1 deletion(-) > > > > diff --git a/trace-output.c b/trace-output.c > > index bfe6331..84b21b0 100644 > > --- a/trace-output.c > > +++ b/trace-output.c > > @@ -929,7 +929,11 @@ tracecmd_add_option(struct tracecmd_output *handle, > > free(option); > > return NULL; > > } > > - memcpy(option->data, data, size); > > + > > + /* Some IDs (like TRACECMD_OPTION_TRACECLOCK) pass NULL data */ > > + if (data) > > + memcpy(option->data, data, size); > > Is this a problem, as when this happens, size should be zero. Does it > crash with data=NULL and size=0, or have you seen size not be zero? I got an ASAN warning, but you are correct - the size was 0 and it did not crash.
Re: [PATCH 2/5] trace-cmd: Fix NULL pointer being passed to memcpy
On Sat, 12 Aug 2017 11:30:44 -0600 Michael Sartain wrote: > Signed-off-by: Michael Sartain > --- > trace-output.c | 6 +- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/trace-output.c b/trace-output.c > index bfe6331..84b21b0 100644 > --- a/trace-output.c > +++ b/trace-output.c > @@ -929,7 +929,11 @@ tracecmd_add_option(struct tracecmd_output *handle, > free(option); > return NULL; > } > - memcpy(option->data, data, size); > + > + /* Some IDs (like TRACECMD_OPTION_TRACECLOCK) pass NULL data */ > + if (data) > + memcpy(option->data, data, size); Is this a problem, as when this happens, size should be zero. Does it crash with data=NULL and size=0, or have you seen size not be zero? -- Steve > + > list_add_tail(&option->list, &handle->options); > > return option;
[PATCH 2/5] trace-cmd: Fix NULL pointer being passed to memcpy
Signed-off-by: Michael Sartain --- trace-output.c | 6 +- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/trace-output.c b/trace-output.c index bfe6331..84b21b0 100644 --- a/trace-output.c +++ b/trace-output.c @@ -929,7 +929,11 @@ tracecmd_add_option(struct tracecmd_output *handle, free(option); return NULL; } - memcpy(option->data, data, size); + + /* Some IDs (like TRACECMD_OPTION_TRACECLOCK) pass NULL data */ + if (data) + memcpy(option->data, data, size); + list_add_tail(&option->list, &handle->options); return option; -- 2.13.2
