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Commit e2f71230 authored by Brian Carlstrom's avatar Brian Carlstrom
Browse files

Revert "Debuggerd now outputs the offset of libc.so on the device as a separate item." 

This reverts commit c031a3b0.

Conflicts:

	debuggerd/debuggerd.c

Change-Id: Ib37ae793bbffdb4a81837bc51171cc62b12abe7d
parent 9a752273

debuggerd/debuggerd.c

+0 −69
Original line number Diff line number Diff line
@@ -37,7 +37,6 @@ 


#include <private/android_filesystem_config.h>



#include <byteswap.h>

#include "debuggerd.h"

#include "utility.h"
@@ -196,73 +195,6 @@ void dump_crash_banner(int tfd, unsigned pid, unsigned tid, int sig) 
    if(sig) dump_fault_addr(tfd, tid, sig);

}



/* After randomization (ASLR), stack contents that point to randomized

 * code become uninterpretable (e.g. can't be resolved to line numbers).

 * Here, we bundle enough information so that stack analysis on the

 * server side can still be performed. This means we are leaking some

 * information about the device (its randomization base). We have to make

 * sure an attacker has no way of intercepting the tombstone.

 */



typedef struct {

    int32_t mmap_addr;

    char tag[4]; /* 'P', 'R', 'E', ' ' */

} prelink_info_t __attribute__((packed));



static inline void set_prelink(long *prelink_addr,

                               prelink_info_t *info)

{

    // We will assume the binary is little-endian, and test the

    // host endianness here.

    unsigned long test_endianness = 0xFF;



    if (sizeof(prelink_info_t) == 8 && prelink_addr) {

        if (*(unsigned char *)&test_endianness)

            *prelink_addr = info->mmap_addr;

        else

            *prelink_addr = bswap_32(info->mmap_addr);

    }

}



static int check_prelinked(const char *fname,

                           long *prelink_addr)

{

    *prelink_addr = 0;

    if (sizeof(prelink_info_t) != 8) return 0;



    int fd = open(fname, O_RDONLY);

    if (fd < 0) return 0;

    off_t end = lseek(fd, 0, SEEK_END);

    int nr = sizeof(prelink_info_t);



    off_t sz = lseek(fd, -nr, SEEK_CUR);

    if ((long)(end - sz) != (long)nr) return 0;

    if (sz == (off_t)-1) return 0;



    prelink_info_t info;

    int num_read = read(fd, &info, nr);

    if (num_read < 0) return 0;

    if (num_read != sizeof(info)) return 0;



    int prelinked = 0;

    if (!strncmp(info.tag, "PRE ", 4)) {

        set_prelink(prelink_addr, &info);

        prelinked = 1;

    }

    if (close(fd) < 0) return 0;

    return prelinked;

}



void dump_randomization_base(int tfd, bool at_fault) {

    bool only_in_tombstone = !at_fault;

    long prelink_addr;

    check_prelinked("/system/lib/libc.so", &prelink_addr);

    _LOG(tfd, only_in_tombstone,

         "\nlibc base address: %08x\n", prelink_addr);

}



/* End of ASLR-related logic. */



static void parse_elf_info(mapinfo *milist, pid_t pid)

{

    mapinfo *mi;
@@ -353,7 +285,6 @@ void dump_crash_report(int tfd, unsigned pid, unsigned tid, bool at_fault) 
        dump_pc_and_lr(tfd, tid, milist, stack_depth, at_fault);

    }



    dump_randomization_base(tfd, at_fault);

    dump_stack_and_code(tfd, tid, milist, stack_depth, sp_list, at_fault);

#elif __i386__

    /* If stack unwinder fails, use the default solution to dump the stack