Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit fd88d16c authored by Robert Sesek's avatar Robert Sesek Committed by Shuah Khan
Browse files

selftests/seccomp: Be more precise with syscall arguments. 



Certain syscall emulation layers strictly check that the number of
arguments match what the syscall handler expects. The KILL_one_arg_one and
KILL_one_arg_six tests passed more parameters than expected to various
syscalls, causing failures in this emulation mode. Instead, test using
syscalls that take the appropriate number of arguments.

Signed-off-by: default avatarRobert Sesek <rsesek@google.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarShuah Khan <shuahkh@osg.samsung.com>
parent 256d0afb

tools/testing/selftests/seccomp/seccomp_bpf.c

+35 −11
Original line number Diff line number Diff line
@@ -29,6 +29,9 @@ 
#include <linux/elf.h>

#include <sys/uio.h>

#include <sys/utsname.h>

#include <sys/fcntl.h>

#include <sys/mman.h>

#include <sys/times.h>



#define _GNU_SOURCE

#include <unistd.h>
@@ -429,14 +432,16 @@ TEST_SIGNAL(KILL_one, SIGSYS) 


TEST_SIGNAL(KILL_one_arg_one, SIGSYS)

{

	void *fatal_address;

	struct sock_filter filter[] = {

		BPF_STMT(BPF_LD|BPF_W|BPF_ABS,

			offsetof(struct seccomp_data, nr)),

		BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0),

		BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_times, 1, 0),

		BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),

		/* Only both with lower 32-bit for now. */

		BPF_STMT(BPF_LD|BPF_W|BPF_ABS, syscall_arg(0)),

		BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, 0x0C0FFEE, 0, 1),

		BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K,

			(unsigned long)&fatal_address, 0, 1),

		BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_KILL),

		BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),

	};
@@ -446,7 +451,8 @@ TEST_SIGNAL(KILL_one_arg_one, SIGSYS) 
	};

	long ret;

	pid_t parent = getppid();

	pid_t pid = getpid();

	struct tms timebuf;

	clock_t clock = times(&timebuf);



	ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);

	ASSERT_EQ(0, ret);
@@ -455,17 +461,22 @@ TEST_SIGNAL(KILL_one_arg_one, SIGSYS) 
	ASSERT_EQ(0, ret);



	EXPECT_EQ(parent, syscall(__NR_getppid));

	EXPECT_EQ(pid, syscall(__NR_getpid));

	/* getpid() should never return. */

	EXPECT_EQ(0, syscall(__NR_getpid, 0x0C0FFEE));

	EXPECT_LE(clock, syscall(__NR_times, &timebuf));

	/* times() should never return. */

	EXPECT_EQ(0, syscall(__NR_times, &fatal_address));

}



TEST_SIGNAL(KILL_one_arg_six, SIGSYS)

{

#ifndef __NR_mmap2

	int sysno = __NR_mmap;

#else

	int sysno = __NR_mmap2;

#endif

	struct sock_filter filter[] = {

		BPF_STMT(BPF_LD|BPF_W|BPF_ABS,

			offsetof(struct seccomp_data, nr)),

		BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, __NR_getpid, 1, 0),

		BPF_JUMP(BPF_JMP|BPF_JEQ|BPF_K, sysno, 1, 0),

		BPF_STMT(BPF_RET|BPF_K, SECCOMP_RET_ALLOW),

		/* Only both with lower 32-bit for now. */

		BPF_STMT(BPF_LD|BPF_W|BPF_ABS, syscall_arg(5)),
@@ -479,7 +490,8 @@ TEST_SIGNAL(KILL_one_arg_six, SIGSYS) 
	};

	long ret;

	pid_t parent = getppid();

	pid_t pid = getpid();

	int fd;

	void *map1, *map2;



	ret = prctl(PR_SET_NO_NEW_PRIVS, 1, 0, 0, 0);

	ASSERT_EQ(0, ret);
@@ -487,10 +499,22 @@ TEST_SIGNAL(KILL_one_arg_six, SIGSYS) 
	ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &prog);

	ASSERT_EQ(0, ret);



	fd = open("/dev/zero", O_RDONLY);

	ASSERT_NE(-1, fd);



	EXPECT_EQ(parent, syscall(__NR_getppid));

	EXPECT_EQ(pid, syscall(__NR_getpid));

	/* getpid() should never return. */

	EXPECT_EQ(0, syscall(__NR_getpid, 1, 2, 3, 4, 5, 0x0C0FFEE));

	map1 = (void *)syscall(sysno,

		NULL, PAGE_SIZE, PROT_READ, MAP_PRIVATE, fd, PAGE_SIZE);

	EXPECT_NE(MAP_FAILED, map1);

	/* mmap2() should never return. */

	map2 = (void *)syscall(sysno,

		 NULL, PAGE_SIZE, PROT_READ, MAP_PRIVATE, fd, 0x0C0FFEE);

	EXPECT_EQ(MAP_FAILED, map2);



	/* The test failed, so clean up the resources. */

	munmap(map1, PAGE_SIZE);

	munmap(map2, PAGE_SIZE);

	close(fd);

}



/* TODO(wad) add 64-bit versus 32-bit arg tests. */