Imbus/xv6-riscv-kernel
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Compile user binary to map text without W and data without X

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Use the flags in elf header to set vm permissions
Modify pgbug() so that usertests text segment is without W
Add test to check app cannot write text segment
This commit is contained in:
Frans Kaashoek 2022-08-15 19:02:19 -04:00
parent 2175c6b0b6
commit cef1b57d4a
3 changed files with 49 additions and 11 deletions
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31
user/usertests.c
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@ -2508,17 +2508,40 @@ stacktest(char *s)
exit(xstatus);
}
// check that writes to text segment fault
void
texttest(char *s)
{
int pid;
int xstatus;
pid = fork();
if(pid == 0) {
volatile int *addr = (int *) 0;
*addr = 10;
exit(1);
} else if(pid < 0){
printf("%s: fork failed\n", s);
exit(1);
}
wait(&xstatus);
if(xstatus == -1) // kernel killed child?
exit(0);
else
exit(xstatus);
}
// regression test. copyin(), copyout(), and copyinstr() used to cast
// the virtual page address to uint, which (with certain wild system
// call arguments) resulted in a kernel page faults.
void *big = (void*) 0xeaeb0b5b00002f5e;
void
pgbug(char *s)
{
char *argv[1];
argv[0] = 0;
exec((char*)0xeaeb0b5b00002f5e, argv);
pipe((int*)0xeaeb0b5b00002f5e);
exec(big, argv);
pipe(big);
exit(0);
}
@ -2607,6 +2630,7 @@ sbrklast(char *s)
exit(1);
}
// does sbrk handle signed int32 wrap-around with
// negative arguments?
void
@ -2617,6 +2641,7 @@ sbrk8000(char *s)
*(top-1) = *(top-1) + 1;
}
// regression test. does write() with an invalid buffer pointer cause
// a block to be allocated for a file that is then not freed when the
// file is deleted? if the kernel has this bug, it will panic: balloc: