Messages in this thread | | | Subject | Re: [Intel-gfx] [PATCH] drm/i915: zero fill vma name buffer | From | Tvrtko Ursulin <> | Date | Thu, 16 Sep 2021 09:23:20 +0100 |
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On 15/09/2021 20:23, Tim Gardner wrote: > In capture_vma() Coverity complains of a possible buffer overrun. Even > though this is a static function where all call sites can be checked, > limiting the copy length could save some future grief. > > CID 93300 (#1 of 1): Copy into fixed size buffer (STRING_OVERFLOW) > 4. fixed_size_dest: You might overrun the 16-character fixed-size string c->name > by copying name without checking the length. > 5. parameter_as_source: Note: This defect has an elevated risk because the > source argument is a parameter of the current function. > 1326 strcpy(c->name, name); > > Fix any possible overflows by using strncpy(). Zero fill the name buffer to > guarantee ASCII string NULL termination. > > Cc: Jani Nikula <jani.nikula@linux.intel.com> > Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com> > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> > Cc: David Airlie <airlied@linux.ie> > Cc: Daniel Vetter <daniel@ffwll.ch> > Cc: intel-gfx@lists.freedesktop.org > Cc: dri-devel@lists.freedesktop.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: Tim Gardner <tim.gardner@canonical.com> > --- > drivers/gpu/drm/i915/i915_gpu_error.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_gpu_error.c b/drivers/gpu/drm/i915/i915_gpu_error.c > index 9cf6ac575de1..154df174e2d7 100644 > --- a/drivers/gpu/drm/i915/i915_gpu_error.c > +++ b/drivers/gpu/drm/i915/i915_gpu_error.c > @@ -1297,10 +1297,11 @@ static bool record_context(struct i915_gem_context_coredump *e, > return simulated; > } > > +#define VMA_NAME_LEN 16 > struct intel_engine_capture_vma { > struct intel_engine_capture_vma *next; > struct i915_vma *vma; > - char name[16]; > + char name[VMA_NAME_LEN]; > }; > > static struct intel_engine_capture_vma * > @@ -1314,7 +1315,7 @@ capture_vma(struct intel_engine_capture_vma *next, > if (!vma) > return next; > > - c = kmalloc(sizeof(*c), gfp); > + c = kzalloc(sizeof(*c), gfp); > if (!c) > return next; > > @@ -1323,7 +1324,7 @@ capture_vma(struct intel_engine_capture_vma *next, > return next; > } > > - strcpy(c->name, name); > + strncpy(c->name, name, VMA_NAME_LEN-1);
GCC is supposed to catch any problems here as you say in the commit message.
But to fix I suggest a single line change to strlcpy(c->name, name, sizeof(c->name)) which always null terminates as bonus.
Probably same in i915_vma_coredump_create() which with strncpy would have a theoretical chance of attempting to copy over a non-null-terminated string.
Regards,
Tvrtko
> c->vma = vma; /* reference held while active */ > > c->next = next; >
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