[Poppler-bugs] [Bug 101501] New: Reading outside bounds at Functions.cc:218

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=101501

            Bug ID: 101501
           Summary: Reading outside bounds at Functions.cc:218
           Product: poppler
           Version: unspecified
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: medium
         Component: general
          Assignee: poppler-bugs at lists.freedesktop.org
          Reporter: foca at salesforce.com

Created attachment 132065
  --> https://bugs.freedesktop.org/attachment.cgi?id=132065&action=edit
Proof of concept

There is a bug reading outside bounds at Functions.cc:218

 212 }
 213 
 214 void IdentityFunction::transform(double *in, double *out) {
 215   int i;
 216 
 217   for (i = 0; i < funcMaxOutputs; ++i) {
 218     out[i] = in[i];
 219   }
 220 }

funcMacOutputs is defined in Functions.h:
#define funcMaxOutputs       32

Parsing the PoC.pdf, this function is called from GfxFunctionShading::getColor:

3957 void GfxFunctionShading::getColor(double x, double y, GfxColor *color) {
3958   double in[2], out[gfxColorMaxComps];
3959   int i;
3960 
3961   // NB: there can be one function with n outputs or n functions with
3962   // one output each (where n = number of color components)
3963   for (i = 0; i < gfxColorMaxComps; ++i) {
3964     out[i] = 0;
3965   }
3966   in[0] = x;
3967   in[1] = y;
3968   for (i = 0; i < nFuncs; ++i) {
3969     funcs[i]->transform(in, &out[i]);
3970   }
3971   for (i = 0; i < gfxColorMaxComps; ++i) {
3972     color->c[i] = dblToCol(out[i]);
3973   }
3974 }

Where the variable in has only 2 elements, instead of the 32 read at
IdentityFunction::transform. So 30 elements are read after the in.

This could be fixed increasing the number of elements for the variable in:
3958   double in[gfxColorMaxComps], out[gfxColorMaxComps];

PoC is attached.

This vulnerability has been found by Offensive Research at Salesforce.com:
Alberto Garcia (@algillera), Francisco Oca (@francisco_oca) & Suleman Ali
(@Salbei_)

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