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test string system call arguments that cross over the end of the last page.

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This commit is contained in:
Robert Morris 2020-08-07 16:56:00 -04:00 committed by Frans Kaashoek
parent 76d6c57ede
commit d8fe1773b2
1 changed files with 53 additions and 0 deletions
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53
user/usertests.c
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@ -22,6 +22,8 @@
char buf[BUFSZ];
char name[3];
// what if you pass ridiculous pointers to system calls
// that read user memory with copyin?
void
copyin(char *s)
{
@ -64,6 +66,8 @@ copyin(char *s)
}
}
// what if you pass ridiculous pointers to system calls
// that write user memory with copyout?
void
copyout(char *s)
{
@ -104,6 +108,7 @@ copyout(char *s)
}
}
// what if you pass ridiculous string pointers to system calls?
void
copyinstr1(char *s)
{
@ -120,6 +125,9 @@ copyinstr1(char *s)
}
}
// what if a string system call argument is exactly the size
// of the kernel buffer it is copied into, so that the null
// would fall just beyond the end of the kernel buffer?
void
copyinstr2(char *s)
{
@ -181,6 +189,50 @@ copyinstr2(char *s)
}
}
// what if a string argument crosses over the end of last user page?
void
copyinstr3(char *s)
{
sbrk(8192);
uint64 top = (uint64) sbrk(0);
if((top % PGSIZE) != 0){
sbrk(PGSIZE - (top % PGSIZE));
}
top = (uint64) sbrk(0);
if(top % PGSIZE){
printf("oops\n");
exit(1);
}
char *b = (char *) (top - 1);
*b = 'x';
int ret = unlink(b);
if(ret != -1){
printf("unlink(%s) returned %d, not -1\n", b, ret);
exit(1);
}
int fd = open(b, O_CREATE | O_WRONLY);
if(fd != -1){
printf("open(%s) returned %d, not -1\n", b, fd);
exit(1);
}
ret = link(b, b);
if(ret != -1){
printf("link(%s, %s) returned %d, not -1\n", b, b, ret);
exit(1);
}
char *args[] = { "xx", 0 };
ret = exec(b, args);
if(ret != -1){
printf("exec(%s) returned %d, not -1\n", b, fd);
exit(1);
}
}
// test O_TRUNC.
void
truncate1(char *s)
@ -2470,6 +2522,7 @@ main(int argc, char *argv[])
{copyout, "copyout"},
{copyinstr1, "copyinstr1"},
{copyinstr2, "copyinstr2"},
{copyinstr3, "copyinstr3"},
{truncate1, "truncate1"},
{truncate2, "truncate2"},
{truncate3, "truncate3"},