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selftest/sigaltstack: Use the AT_MINSIGSTKSZ aux vector if available

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The SIGSTKSZ constant may not represent enough stack size in some
architectures as the hardware state size grows.

Use getauxval(AT_MINSIGSTKSZ) to increase the stack size.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Len Brown <len.brown@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20210518200320.17239-5-chang.seok.bae@intel.com
This commit is contained in:
Chang S. Bae
2021-05-18 13:03:18 -07:00
committed by Borislav Petkov
parent 1c33bb0507
commit bdf6c8b84a
1 changed files with 15 additions and 5 deletions
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20
tools/testing/selftests/sigaltstack/sas.c
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@@ -17,6 +17,7 @@
#include <string.h> #include <string.h>
#include <assert.h> #include <assert.h>
#include <errno.h> #include <errno.h>
#include <sys/auxv.h>
#include "../kselftest.h" #include "../kselftest.h"
@@ -24,6 +25,11 @@
#define SS_AUTODISARM (1U << 31) #define SS_AUTODISARM (1U << 31)
#endif #endif
#ifndef AT_MINSIGSTKSZ
#define AT_MINSIGSTKSZ 51
#endif
static unsigned int stack_size;
static void *sstack, *ustack; static void *sstack, *ustack;
static ucontext_t uc, sc; static ucontext_t uc, sc;
static const char *msg = "[OK]\tStack preserved"; static const char *msg = "[OK]\tStack preserved";
@@ -47,7 +53,7 @@ void my_usr1(int sig, siginfo_t *si, void *u)
#endif #endif
if (sp < (unsigned long)sstack || if (sp < (unsigned long)sstack ||
sp >= (unsigned long)sstack + SIGSTKSZ) { sp >= (unsigned long)sstack + stack_size) {
ksft_exit_fail_msg("SP is not on sigaltstack\n"); ksft_exit_fail_msg("SP is not on sigaltstack\n");
} }
/* put some data on stack. other sighandler will try to overwrite it */ /* put some data on stack. other sighandler will try to overwrite it */
@@ -108,6 +114,10 @@ int main(void)
stack_t stk; stack_t stk;
int err; int err;
/* Make sure more than the required minimum. */
stack_size = getauxval(AT_MINSIGSTKSZ) + SIGSTKSZ;
ksft_print_msg("[NOTE]\tthe stack size is %lu\n", stack_size);
ksft_print_header(); ksft_print_header();
ksft_set_plan(3); ksft_set_plan(3);
@@ -117,7 +127,7 @@ int main(void)
sigaction(SIGUSR1, &act, NULL); sigaction(SIGUSR1, &act, NULL);
act.sa_sigaction = my_usr2; act.sa_sigaction = my_usr2;
sigaction(SIGUSR2, &act, NULL); sigaction(SIGUSR2, &act, NULL);
sstack = mmap(NULL, SIGSTKSZ, PROT_READ | PROT_WRITE, sstack = mmap(NULL, stack_size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0); MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
if (sstack == MAP_FAILED) { if (sstack == MAP_FAILED) {
ksft_exit_fail_msg("mmap() - %s\n", strerror(errno)); ksft_exit_fail_msg("mmap() - %s\n", strerror(errno));
@@ -139,7 +149,7 @@ int main(void)
} }
stk.ss_sp = sstack; stk.ss_sp = sstack;
stk.ss_size = SIGSTKSZ; stk.ss_size = stack_size;
stk.ss_flags = SS_ONSTACK | SS_AUTODISARM; stk.ss_flags = SS_ONSTACK | SS_AUTODISARM;
err = sigaltstack(&stk, NULL); err = sigaltstack(&stk, NULL);
if (err) { if (err) {
@@ -161,7 +171,7 @@ int main(void)
} }
} }
ustack = mmap(NULL, SIGSTKSZ, PROT_READ | PROT_WRITE, ustack = mmap(NULL, stack_size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0); MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
if (ustack == MAP_FAILED) { if (ustack == MAP_FAILED) {
ksft_exit_fail_msg("mmap() - %s\n", strerror(errno)); ksft_exit_fail_msg("mmap() - %s\n", strerror(errno));
@@ -170,7 +180,7 @@ int main(void)
getcontext(&uc); getcontext(&uc);
uc.uc_link = NULL; uc.uc_link = NULL;
uc.uc_stack.ss_sp = ustack; uc.uc_stack.ss_sp = ustack;
uc.uc_stack.ss_size = SIGSTKSZ; uc.uc_stack.ss_size = stack_size;
makecontext(&uc, switch_fn, 0); makecontext(&uc, switch_fn, 0);
raise(SIGUSR1); raise(SIGUSR1);