On Mon, Nov 21, 2022 at 10:59:44AM +0100, Kevin Brodsky wrote:
On 18/11/2022 13:21, Beata Michalska wrote:
|diff --git a/lib/test_printf.c b/lib/test_printf.c index 07309c45f327..1b877b68a30d 100644 --- a/lib/test_printf.c +++ b/lib/test_printf.c @@ -24,6 +24,10 @@ #include <linux/property.h> +#ifdef __CHERI__ +#include <cheriintrin.h> +#endif + #include "../tools/testing/selftests/kselftest_module.h" #define BUF_SIZE 256 @@ -755,6 +759,159 @@ errptr(void) #endif } +static void __init +capability_pointer(void) +{ +#ifdef __CHERI__ + enum action { + /* No action - use as is */ + CAP_AXN_NONE, + /* Clear capability tag */ + CAP_TAG_CLEAR, + /* Derive null-capability */ + CAP_NULL_DERIVE + }; +
- struct { + const char *plain_fmt; + const char *fmt; + const char
*expected; + int action; + } const setup[] = { + { + .plain_fmt = "%lp", + .fmt = "%lpx", + .expected = "1:d800400059ab89ab:"PTR_STR, + .action = CAP_AXN_NONE, + }, + { + .plain_fmt = "%#lp", + .fmt = "%#lpx", + .expected = "0x"PTR_STR" [rwRW,0xffff0123456789ab-0xffff0123456799ab]", + .action = CAP_AXN_NONE, + }, + { + .plain_fmt = "%lp", + .fmt = "%lpx", + .expected = "0:d800400059ab89ab:"PTR_STR, + .action = CAP_TAG_CLEAR, + }, + { + .plain_fmt = "%#lp", + .fmt = "%#lpx", + .expected = "0x"PTR_STR" [rwRW,0xffff0123456789ab-0xffff0123456799ab] (invalid)",
- .action = CAP_TAG_CLEAR, + }, + { + .plain_fmt = "%lp", + .fmt =
"%lpx", + .expected = PTR_STR, + .action = CAP_NULL_DERIVE, + }, + { + .plain_fmt = "%#lp", + .fmt = "%#lpx", + .expected = PTR_STR, + .action = CAP_NULL_DERIVE, + } + }; + + char buf[PLAIN_BUF_SIZE]; + const char * const cap_fmt_non_hashed[] = {"%lp", "%#lp"}; + int nchars; + + void * __capability cap = cheri_ddc_get(); + + /* Expecting basic permissions to be set */ + size_t perms = CHERI_PERM_GLOBAL | CHERI_PERM_LOAD | CHERI_PERM_LOAD_CAP | + CHERI_PERM_STORE | CHERI_PERM_STORE_CAP; + + size_t bounds = 4096; + + cap = cheri_address_set(cap, (ptraddr_t)PTR); + cap = cheri_perms_and(cap, perms); + /* + * Basic checks so that the actual output can be safely compared + * to the expected one + */ + if (!cheri_tag_get(cap) || cheri_perms_get(cap) != perms + || cheri_is_sealed(cap)) { + pr_warn("Failed to create capability for testing - skipping"); + skipped_tests += no_hash_pointers ? + ARRAY_SIZE(cap_fmt_non_hashed) + ARRAY_SIZE(setup) * 2 : + ARRAY_SIZE(cap_fmt_non_hashed) + ARRAY_SIZE(setup); + return; + } + + cap = cheri_bounds_set_exact(cap, bounds); + + /* Verify hashing */ + if (no_hash_pointers) { + pr_warn("Skipping capability hashing tests\n"); + skipped_tests += ARRAY_SIZE(cap_fmt_non_hashed); + goto non_hashed; + } + + for (int i = 0; i < ARRAY_SIZE(cap_fmt_non_hashed); ++i) { + nchars = snprintf(buf, PLAIN_BUF_SIZE, cap_fmt_non_hashed[i], + cap); + + total_tests++; + /*
- Should be ADDR_WIDTH in this case , but hey, let's not be picky +
- about it, at least not here ... not yet ... + */ + if (nchars !=
PTR_WIDTH) { + /* + * This also covers the case when the value has not been + * actually hashed, as nchars would then be greater than + * PTR_WIDTH + */ + pr_warn("Something went wrong with hashing capability value\n"); + failed_tests++; + continue; + } + + if (strncmp(buf, PTR_VAL_NO_CRNG, PTR_WIDTH) == 0) { + pr_warn("crng possibly not yet initialized - capability value buffer contains "%s"", + PTR_VAL_NO_CRNG); + } else if (strncmp(buf, ZEROS, strlen(ZEROS)) != 0) { + pr_warn("Unexpected format for supposedly hashed capability value\n"); + failed_tests++; + continue; + } + } + +non_hashed: + for (int i = 0; i < ARRAY_SIZE(setup); ++i) { + void * __capability current_cap; + + switch (setup[i].action) { + case CAP_TAG_CLEAR: + current_cap = cheri_tag_clear(cap); + break; + case CAP_NULL_DERIVE: + /* Null-derived capability */ + current_cap = cheri_address_set(0, cheri_address_get(cap)); + break; + default: + current_cap = cap; + break; + } + + if (no_hash_pointers) + test(setup[i].expected, setup[i].plain_fmt, current_cap); + else + ++skipped_tests; + + test(setup[i].expected, setup[i].fmt, current_cap); + } + + return;|
Not needed any more.
Nothing else to complain about, so if you're happy with it I can remove it myself when applying the patch.
That would be appreciated so go ahead with the change. Thanks
--- BR B.
Kevin
|+ +#endif /* CONFIG_ARM64_MORELLO */ +} + static void __init test_pointer(void) {|