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GAP- Generating Access Permissions IJAZ AHMED advised by : NESTOR CATANO

GAP- Generating Access Permissions IJAZ AHMED advised by : NESTOR CATANO. GAP. It takes a Java program and generates the likely access permissions It implements a modular and static analysis of Java programs. How it Works?

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GAP- Generating Access Permissions IJAZ AHMED advised by : NESTOR CATANO

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  1. GAP- Generating Access Permissions IJAZ AHMED advised by : NESTOR CATANO http://www3.uma.pt/ncatano/aeminium/GAP.html

  2. GAP • It takes a Java program and generates the likely access permissions • It implements a modular and static analysis of Java programs. • How it Works? • It extracts the read, write and alias information from a Java source code through AST • It generates a graph for every method that shows read, write and alias information • It traverses the graph and gathers likely information • It works in two mode i.e. Read mode and Write mode • An implementation of the algorithm as an Eclipse plug-in is on way http://www3.uma.pt/ncatano/aeminium/GAP.html

  3. General Idea http://www3.uma.pt/ncatano/aeminium/GAP.html

  4. Notations, Terminology and Concepts • Method Node • an abstraction to represent method local environment • Context Node • an abstraction to represent external world/other references • Reference Nodes • class fields, parameters, local variables • Object Nodes • represent physical memory of objects • Edges • Read Edge • Write Edge • Pointe Edge http://www3.uma.pt/ncatano/aeminium/GAP.html

  5. Some Rules • General Idea • To represent the read , write and alias information with edges • Check the types of edges and number of Pointe’ edges to define access Permissions • Types of Rules • Graph Construction Rules • Pre Access Permissions Rules (Graph Traversal) • Post Access Permission Rules (Graph Traversal) http://www3.uma.pt/ncatano/aeminium/GAP.html

  6. An Example- JAVA Program publicclass B{ int a; } publicclass A { B x,y,r; publicObject method1(B z, B w){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } } http://www3.uma.pt/ncatano/aeminium/GAP.html

  7. Analysis of method1 High Level Algorithm Make the set Z = {Fields} U {Parameters} Make the set M= object of set Z Make the set U = Z U M U { method, Context} Step 1- Create nodes for all items in set U Step 2- Apply the Pointe-Rule for elements in set Z and set M Step 3- Apply the rule Context-R if you are in mode R, otherwise apply rule Context-RW if you are in mode RW. publicclass A { B x,y,r; publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w z x y x_object y_object z_object w_object context http://www3.uma.pt/ncatano/aeminium/GAP.html

  8. Analysis of method1 High Level Algorithm Make the set Z = {Fields} U {Parameters} Make the set M= object of set Z Make the set U = Z U M U { method, Context} Step 1- Create nodes for all items in set U Step 2- Apply the Pointe-Rule for elements in set Z and set M Step 3- Apply the rule Context-R if you are in mode R, otherwise apply rule Context-RW if you are in mode RW. publicclass A { B x,y,r; publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w z x y P P P P x_object y_object z_object w_object context http://www3.uma.pt/ncatano/aeminium/GAP.html

  9. Analysis of method1 High Level Algorithm Make the set Z = {Fields} U {Parameters} Make the set M= object of set Z Make the set U = Z U M U { method, Context} Step 1- Create nodes for all items in set U Step 2- Apply the Pointe-Rule for elements in set Z and set M Step 3- Apply the rule Context-R if you are in mode R, otherwise apply rule Context-RW if you are in mode RW. publicclass A { B x,y,r; publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w z x y P P P P x_object y_object z_object w_object R R R R context http://www3.uma.pt/ncatano/aeminium/GAP.html

  10. Analysis of method1 High Level Algorithm Step 4- For every statement s in the method body, apply a graph construction rule according to the syntax of s. Step 5- Generate Pre-Permissions by applying Pre-Traversal Rules for items in set Z Step 6- Generate Post-Permissions by applying Post-Traversal Rules for items in set Z. publicclass A { B x,y,r; publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w z x y P P P P x_object y_object z_object w_object R R R R context http://www3.uma.pt/ncatano/aeminium/GAP.html

  11. Analysis of method1 High Level Algorithm Step 4- For every statement s in the method body, apply a graph construction rule according to the syntax of s. Step 5- Generate Pre-Permissions by applying Pre-Traversal Rules for items in set Z Step 6- Generate Post-Permissions by applying Post-Traversal Rules for items in set Z. publicclass A { B x,y,r; publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w z x y P P P P x_object y_object z_object w_object R R R R context http://www3.uma.pt/ncatano/aeminium/GAP.html

  12. Analysis of method1 High Level Algorithm Step 4- For every statement s in the method body, apply a graph construction rule according to the syntax of s. Step 5- Generate Pre-Permissions by applying Pre-Traversal Rules for items in set Z Step 6- Generate Post-Permissions by applying Post-Traversal Rules for items in set Z. publicclass A { B x,y,r; publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w z x y P P P P x_object y_object z_object w_object R R R R context http://www3.uma.pt/ncatano/aeminium/GAP.html

  13. Analysis of method1 High Level Algorithm Step 4- For every statement s in the method body, apply a graph construction rule according to the syntax of s. Step 5- Generate Pre-Permissions by applying Pre-Traversal Rules for items in set Z Step 6- Generate Post-Permissions by applying Post-Traversal Rules for items in set Z. publicclass A { B x,y,r; publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w t z x y P P P P P x_object y_object z_object w_object R R R R context http://www3.uma.pt/ncatano/aeminium/GAP.html

  14. Analysis of method1 High Level Algorithm Step 4- For every statement s in the method body, apply a graph construction rule according to the syntax of s. Step 5- Generate Pre-Permissions by applying Pre-Traversal Rules for items in set Z Step 6- Generate Post-Permissions by applying Post-Traversal Rules for items in set Z. publicclass A { B x,y,r; publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w t z x y P P P P P x_object y_object z_object w_object R R R R context http://www3.uma.pt/ncatano/aeminium/GAP.html

  15. Analysis of method1 High Level Algorithm Step 4- For every statement s in the method body, apply a graph construction rule according to the syntax of s. Step 5- Generate Pre-Permissions by applying Pre-Traversal Rules for items in set Z Step 6- Generate Post-Permissions by applying Post-Traversal Rules for items in set Z. publicclass A { B x,y,r; publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w t z x y P P P P x_object y_object z_object w_object R R R R context http://www3.uma.pt/ncatano/aeminium/GAP.html

  16. Analysis of method1 High Level Algorithm Step 4- For every statement s in the method body, apply a graph construction rule according to the syntax of s. Step 5- Generate Pre-Permissions by applying Pre-Traversal Rules for items in set Z Step 6- Generate Post-Permissions by applying Post-Traversal Rules for items in set Z. publicclass A { B x,y,r; publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w t z x y P P P P x_object y_object z_object w_object R R R R context http://www3.uma.pt/ncatano/aeminium/GAP.html

  17. Analysis of method1 High Level Algorithm Step 4- For every statement s in the method body, apply a graph construction rule according to the syntax of s. Step 5- Generate Pre-Permissions by applying Pre-Traversal Rules for items in set Z Step 6- Generate Post-Permissions by applying Post-Traversal Rules for items in set Z. publicclass A { B x,y,r; publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w t z x y w P P P P x_object y_object z_object w_object R R R R context http://www3.uma.pt/ncatano/aeminium/GAP.html

  18. Analysis of method1 High Level Algorithm Step 4- For every statement s in the method body, apply a graph construction rule according to the syntax of s. Step 5- Generate Pre-Permissions by applying Pre-Traversal Rules for items in set Z Step 6- Generate Post-Permissions by applying Post-Traversal Rules for items in set Z. publicclass A { B x,y,r; publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w t z x y w P P P P x_object y_object z_object w_object R R R R context http://www3.uma.pt/ncatano/aeminium/GAP.html

  19. Analysis of method1 High Level Algorithm Step 4- For every statement s in the method body, apply a graph construction rule according to the syntax of s. Step 5- Generate Pre-Permissions by applying Pre-Traversal Rules for items in set Z Step 6- Generate Post-Permissions by applying Post-Traversal Rules for items in set Z. publicclass A { B x,y,r; publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w t z x y w R P P P P x_object y_object z_object w_object R R R R context http://www3.uma.pt/ncatano/aeminium/GAP.html

  20. Analysis of method1 High Level Algorithm Step 4- For every statement s in the method body, apply a graph construction rule according to the syntax of s. Step 5- Generate Pre-Permissions by applying Pre-Traversal Rules for items in set Z Step 6- Generate Post-Permissions by applying Post-Traversal Rules for items in set Z. publicclass A { B x,y,r; publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w t z x y w R P P P P x_object y_object z_object w_object R R R R context http://www3.uma.pt/ncatano/aeminium/GAP.html

  21. Analysis of method1 High Level Algorithm Step 4- For every statement s in the method body, apply a graph construction rule according to the syntax of s. Step 5- Generate Pre-Permissions by applying Pre-Traversal Rules for items in set Z Step 6- Generate Post-Permissions by applying Post-Traversal Rules for items in set Z. publicclass A { B x,y,r; full(x),full(y),full(z),Immutable(w)  publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w t z x y w R P P P P x_object y_object z_object w_object R R R R context http://www3.uma.pt/ncatano/aeminium/GAP.html

  22. Analysis of method1 High Level Algorithm Step 4- For every statement s in the method body, apply a graph construction rule according to the syntax of s. Step 5- Generate Pre-Permissions by applying Pre-Traversal Rules for items in set Z Step 6- Generate Post-Permissions by applying Post-Traversal Rules for items in set Z. publicclass A { B x,y,r; full(x),full(y),full(z),Immutable(w)  publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w t z x y w R P P P P x_object y_object z_object w_object R R R R context http://www3.uma.pt/ncatano/aeminium/GAP.html

  23. Analysis of method1 High Level Algorithm Step 4- For every statement s in the method body, apply a graph construction rule according to the syntax of s. Step 5- Generate Pre-Permissions by applying Pre-Traversal Rules for items in set Z Step 6- Generate Post-Permissions by applying Post-Traversal Rules for items in set Z. publicclass A { B x,y,r; full(x),full(y),full(z),Immutable(w)  Immutable(x),Immutable(y) publicObject method1(B z, B w ){ x=w; Object t=x; y=t; z.a=15; System.print.out(x.a+w.a+t.a); return y; } method1 w t z x y w R P P P P x_object y_object z_object w_object R R R R context http://www3.uma.pt/ncatano/aeminium/GAP.html

  24. Conclusion • Present Status • Can generate access permission for simple program • Tested with some examples • Under development • Future Work • Parser require further iterations to parse complex program • Mapping of GAP Specifications with Plural Syntax • Planning to run GAP on the MTTS application as a bench mark • Integrate as an Eclipse plug-in with Plural • Link • http://www3.uma.pt/ncatano/aeminium/GAP.html http://www3.uma.pt/ncatano/aeminium/GAP.html

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