"value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix a kernel verifier crash in stacksafe()\n\nDaniel Hodges reported a kernel verifier crash when playing with sched-ext.\nFurther investigation shows that the crash is due to invalid memory access\nin stacksafe(). More specifically, it is the following code:\n\n if (exact != NOT_EXACT &&\n old->stack[spi].slot_type[i % BPF_REG_SIZE] !=\n cur->stack[spi].slot_type[i % BPF_REG_SIZE])\n return false;\n\nThe 'i' iterates old->allocated_stack.\nIf cur->allocated_stack < old->allocated_stack the out-of-bound\naccess will happen.\n\nTo fix the issue add 'i >= cur->allocated_stack' check such that if\nthe condition is true, stacksafe() should fail. Otherwise,\ncur->stack[spi].slot_type[i % BPF_REG_SIZE] memory access is legal."
"value":"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: bpf: Se corrige un fallo del verificador del kernel en stacksafe() Daniel Hodges inform\u00f3 de un fallo del verificador del kernel al jugar con sched-ext. Una investigaci\u00f3n m\u00e1s profunda muestra que el fallo se debe a un acceso a memoria no v\u00e1lido en stacksafe(). M\u00e1s espec\u00edficamente, es el siguiente c\u00f3digo: if (exact != NOT_EXACT && old->stack[spi].slot_type[i % BPF_REG_SIZE] != cur->stack[spi].slot_type[i % BPF_REG_SIZE]) return false; La 'i' itera old->allocated_stack. Si cur->allocated_stack < old->allocated_stack, se producir\u00e1 el acceso fuera de l\u00edmites. Para solucionar el problema, agregue la comprobaci\u00f3n 'i >= cur->allocated_stack' de modo que, si la condici\u00f3n es verdadera, stacksafe() deber\u00eda fallar. De lo contrario, el acceso a la memoria cur->stack[spi].slot_type[i % BPF_REG_SIZE] es legal."