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Commit 0b4836f2 authored by Mike Dodd's avatar Mike Dodd Committed by Jean-Baptiste Queru
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Fix debuggerd (native crash dump). 

Change 44659e90 (6cc49230 in AOSP) introduced walking
both the symbol table and dynamic symbol table. The problem
is that it was dereferencing values whether or not the two tables
were both present, which could wind up reading from invalid memory.
The read from a bad address would cause debuggerd itself to crash,
which isn't handled.

Change-Id: Ie936f660018b1980dee5b6ed669588db861f1a79
parent d3f59eab

debuggerd/symbol_table.c

+19 −10
Original line number Diff line number Diff line
@@ -94,17 +94,26 @@ struct symbol_table *symbol_table_create(const char *filename) 
    table->name = strdup(filename);

    table->num_symbols = 0;



    Elf32_Sym *dynsyms = (Elf32_Sym*)(base + shdr[dynsym_idx].sh_offset);

    Elf32_Sym *syms = (Elf32_Sym*)(base + shdr[sym_idx].sh_offset);



    int dynnumsyms = shdr[dynsym_idx].sh_size / shdr[dynsym_idx].sh_entsize;

    int numsyms = shdr[sym_idx].sh_size / shdr[sym_idx].sh_entsize;

    Elf32_Sym *dynsyms = NULL;

    Elf32_Sym *syms = NULL;

    int dynnumsyms = 0;

    int numsyms = 0;

    char *dynstr = NULL;

    char *str = NULL;



    if (dynsym_idx != -1) {

        dynsyms = (Elf32_Sym*)(base + shdr[dynsym_idx].sh_offset);

        dynnumsyms = shdr[dynsym_idx].sh_size / shdr[dynsym_idx].sh_entsize;

        int dynstr_idx = shdr[dynsym_idx].sh_link;

    int str_idx = shdr[sym_idx].sh_link;

        dynstr = base + shdr[dynstr_idx].sh_offset;

    }



    char *dynstr = base + shdr[dynstr_idx].sh_offset;

    char *str = base + shdr[str_idx].sh_offset;

    if (sym_idx != -1) {

        syms = (Elf32_Sym*)(base + shdr[sym_idx].sh_offset);

        numsyms = shdr[sym_idx].sh_size / shdr[sym_idx].sh_entsize;

        int str_idx = shdr[sym_idx].sh_link;

        str = base + shdr[str_idx].sh_offset;

    }



    int symbol_count = 0;

    int dynsymbol_count = 0;
@@ -134,7 +143,7 @@ struct symbol_table *symbol_table_create(const char *filename) 
    }



    // Now, create an entry in our symbol table structure for each symbol...

    table->num_symbols += symbol_count + dynsymbol_count;;

    table->num_symbols += symbol_count + dynsymbol_count;

    table->symbols = malloc(table->num_symbols * sizeof(struct symbol));

    if(!table->symbols) {

        free(table);