Skip to content

Commit

Permalink
selftests/powerpc: Add pkey helpers for rights
Browse files Browse the repository at this point in the history 
This adds some new pkey-related helper to print
access rights of a pkey in the "rwx" format and
to generate different valid combinations of pkey
rights starting from a given combination.

Signed-off-by: Sandipan Das <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/6cc1c7d1f686618668a3e090f1d0c2a4cd9dea3f.1595821792.git.sandipan@linux.ibm.com
  • Loading branch information
@sandip4n @mpe
sandip4n authored and mpe committed Jul 29, 2020
1 parent 128d3d0 commit 264d7fc
Show file tree
Hide file tree
Showing 2 changed files with 48 additions and 16 deletions.
28 changes: 28 additions & 0 deletions tools/testing/selftests/powerpc/include/pkeys.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -105,4 +105,32 @@ int siginfo_pkey(siginfo_t *si)
#endif
}

#define pkey_rights(r) ({ \
static char buf[4] = "rwx"; \
unsigned int amr_bits; \
if ((r) & PKEY_DISABLE_EXECUTE) \
buf[2] = '-'; \
amr_bits = (r) & PKEY_BITS_MASK; \
if (amr_bits & PKEY_DISABLE_WRITE) \
buf[1] = '-'; \
if (amr_bits & PKEY_DISABLE_ACCESS & ~PKEY_DISABLE_WRITE) \
buf[0] = '-'; \
buf; \
})

unsigned long next_pkey_rights(unsigned long rights)
{
if (rights == PKEY_DISABLE_ACCESS)
return PKEY_DISABLE_EXECUTE;
else if (rights == (PKEY_DISABLE_ACCESS | PKEY_DISABLE_EXECUTE))
return 0;

if ((rights & PKEY_BITS_MASK) == 0)
rights |= PKEY_DISABLE_WRITE;
else if ((rights & PKEY_BITS_MASK) == PKEY_DISABLE_WRITE)
rights |= PKEY_DISABLE_ACCESS;

return rights;
}

#endif /* _SELFTESTS_POWERPC_PKEYS_H */
36 changes: 20 additions & 16 deletions tools/testing/selftests/powerpc/mm/pkey_exec_prot.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -102,6 +102,7 @@ static void segv_handler(int signum, siginfo_t *sinfo, void *ctx)
static int test(void)
{
struct sigaction segv_act, trap_act;
unsigned long rights;
int pkey, ret, i;

ret = pkeys_unsupported();
Expand Down Expand Up @@ -150,7 +151,8 @@ static int test(void)
insns[numinsns - 1] = PPC_INST_BLR;

/* Allocate a pkey that restricts execution */
pkey = sys_pkey_alloc(0, PKEY_DISABLE_EXECUTE);
rights = PKEY_DISABLE_EXECUTE;
pkey = sys_pkey_alloc(0, rights);
FAIL_IF(pkey < 0);

/*
Expand All @@ -175,8 +177,8 @@ static int test(void)
*/
remaining_faults = 0;
FAIL_IF(sys_pkey_mprotect(insns, pgsize, PROT_EXEC, pkey) != 0);
printf("read from %p, pkey is execute-disabled, access-enabled\n",
(void *) fault_addr);
printf("read from %p, pkey permissions are %s\n", fault_addr,
pkey_rights(rights));
i = *fault_addr;
FAIL_IF(remaining_faults != 0);

Expand All @@ -192,12 +194,13 @@ static int test(void)
*/
remaining_faults = 1;
FAIL_IF(sys_pkey_mprotect(insns, pgsize, PROT_EXEC, pkey) != 0);
printf("write to %p, pkey is execute-disabled, access-enabled\n",
(void *) fault_addr);
printf("write to %p, pkey permissions are %s\n", fault_addr,
pkey_rights(rights));
*fault_addr = PPC_INST_TRAP;
FAIL_IF(remaining_faults != 0 || fault_code != SEGV_ACCERR);

/* The following three cases will generate SEGV_PKUERR */
rights |= PKEY_DISABLE_ACCESS;
fault_type = PKEY_DISABLE_ACCESS;
fault_pkey = pkey;

Expand All @@ -211,9 +214,9 @@ static int test(void)
*/
remaining_faults = 1;
FAIL_IF(sys_pkey_mprotect(insns, pgsize, PROT_EXEC, pkey) != 0);
printf("read from %p, pkey is execute-disabled, access-disabled\n",
(void *) fault_addr);
pkey_set_rights(pkey, PKEY_DISABLE_ACCESS);
pkey_set_rights(pkey, rights);
printf("read from %p, pkey permissions are %s\n", fault_addr,
pkey_rights(rights));
i = *fault_addr;
FAIL_IF(remaining_faults != 0 || fault_code != SEGV_PKUERR);

Expand All @@ -228,9 +231,9 @@ static int test(void)
*/
remaining_faults = 2;
FAIL_IF(sys_pkey_mprotect(insns, pgsize, PROT_EXEC, pkey) != 0);
printf("write to %p, pkey is execute-disabled, access-disabled\n",
(void *) fault_addr);
pkey_set_rights(pkey, PKEY_DISABLE_ACCESS);
pkey_set_rights(pkey, rights);
printf("write to %p, pkey permissions are %s\n", fault_addr,
pkey_rights(rights));
*fault_addr = PPC_INST_NOP;
FAIL_IF(remaining_faults != 0 || fault_code != SEGV_ACCERR);

Expand All @@ -251,8 +254,8 @@ static int test(void)
remaining_faults = 1;
FAIL_IF(sys_pkey_mprotect(insns, pgsize, PROT_EXEC, pkey) != 0);
pkey_set_rights(pkey, PKEY_DISABLE_ACCESS);
printf("execute at %p, pkey is execute-disabled, access-disabled\n",
(void *) fault_addr);
printf("execute at %p, pkey permissions are %s\n", fault_addr,
pkey_rights(rights));
asm volatile("mtctr %0; bctrl" : : "r"(insns));
FAIL_IF(remaining_faults != 0 || fault_code != SEGV_PKUERR);

Expand All @@ -261,7 +264,8 @@ static int test(void)
* fully permissive.
*/
sys_pkey_free(pkey);
pkey = sys_pkey_alloc(0, 0);
rights = 0;
pkey = sys_pkey_alloc(0, rights);

/*
* Jump to the executable region when AMR bits are not set
Expand All @@ -274,8 +278,8 @@ static int test(void)
fault_pkey = pkey;
remaining_faults = 0;
FAIL_IF(sys_pkey_mprotect(insns, pgsize, PROT_EXEC, pkey) != 0);
printf("execute at %p, pkey is execute-enabled, access-enabled\n",
(void *) fault_addr);
printf("execute at %p, pkey permissions are %s\n", fault_addr,
pkey_rights(rights));
asm volatile("mtctr %0; bctrl" : : "r"(insns));
FAIL_IF(remaining_faults != 0);

Expand Down

0 comments on commit 264d7fc

Please sign in to comment.