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Fixing invalid reads in find_elf_note due to setenv invocation

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Resolves issue on mailing list and Red Hat Bugzilla 1163404.
This commit is contained in:
Jan Rybar 2016-08-05 15:21:49 +02:00
parent b4fdb27a05
commit ecabdaca41
1 changed files with 62 additions and 7 deletions
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69
proc/sysinfo.c
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@ -36,6 +36,9 @@
#include <netinet/in.h> /* htons */
#endif
#include <link.h>
#include <elf.h>
long smp_num_cpus; /* number of CPUs */
long page_bytes; /* this architecture's page size */
@ -249,15 +252,67 @@ static void old_Hertz_hack(void){
extern char** environ;
/* for ELF executables, notes are pushed before environment and args */
static unsigned long find_elf_note(unsigned long findme){
static unsigned long find_elf_note(unsigned long type)
{
ElfW(auxv_t) auxv_struct;
ElfW(auxv_t) *auxv_temp;
FILE *fd;
int i;
static ElfW(auxv_t) *auxv = NULL;
unsigned long *ep = (unsigned long *)environ;
while(*ep++);
while(*ep){
if(ep[0]==findme) return ep[1];
ep+=2;
unsigned long ret_val = NOTE_NOT_FOUND;
if(!auxv) {
fd = fopen("/proc/self/auxv", "rb");
if(!fd) { // can't open auxv? that could be caused by euid change
// ... and we need to fall back to the old and unsafe
// ... method that doesn't work when calling library
// ... functions with dlopen -> FIXME :(
while(*ep++); // for ELF executables, notes are pushed
while(*ep){ // ... before environment and args
if(ep[0]==type) return ep[1];
ep+=2;
}
return NOTE_NOT_FOUND;
}
auxv = (ElfW(auxv_t) *) malloc(getpagesize());
if (!auxv) {
perror("malloc");
exit(EXIT_FAILURE);
}
i = 0;
do {
fread(&auxv_struct, sizeof(ElfW(auxv_t)), 1, fd);
auxv[i] = auxv_struct;
i++;
} while (auxv_struct.a_type != AT_NULL);
fclose(fd);
}
return NOTE_NOT_FOUND;
auxv_temp = auxv;
i = 0;
do {
if(auxv_temp[i].a_type == type) {
ret_val = (unsigned long)auxv_temp[i].a_un.a_val;
break;
}
i++;
} while (auxv_temp[i].a_type != AT_NULL);
if (auxv){
auxv_temp = NULL;
free(auxv);
auxv = NULL;
}
return ret_val;
}
int have_privs;