[PATCH AUTOSEL 5.15 01/23] selftests/bpf: Add test for bpf_timer overwriting crash

[PATCH AUTOSEL 5.15 01/23] selftests/bpf: Add test for bpf_timer overwriting crash

[Sasha Levin]

From: Kumar Kartikeya Dwivedi <memxor@gmail.com>

[ Upstream commit a7e75016a0753c24d6c995bc02501ae35368e333 ]

Add a test that validates that timer value is not overwritten when doing
a copy_map_value call in the kernel. Without the prior fix, this test
triggers a crash.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20220209070324.1093182-3-memxor@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 .../selftests/bpf/prog_tests/timer_crash.c    | 32 +++++++++++
 .../testing/selftests/bpf/progs/timer_crash.c | 54 +++++++++++++++++++
 2 files changed, 86 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/timer_crash.c
 create mode 100644 tools/testing/selftests/bpf/progs/timer_crash.c

diff --git a/tools/testing/selftests/bpf/prog_tests/timer_crash.c b/tools/testing/selftests/bpf/prog_tests/timer_crash.c
new file mode 100644
index 0000000000000..f74b82305da8c
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/timer_crash.c
@@ -0,0 +1,32 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include "timer_crash.skel.h"
+
+enum {
+	MODE_ARRAY,
+	MODE_HASH,
+};
+
+static void test_timer_crash_mode(int mode)
+{
+	struct timer_crash *skel;
+
+	skel = timer_crash__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "timer_crash__open_and_load"))
+		return;
+	skel->bss->pid = getpid();
+	skel->bss->crash_map = mode;
+	if (!ASSERT_OK(timer_crash__attach(skel), "timer_crash__attach"))
+		goto end;
+	usleep(1);
+end:
+	timer_crash__destroy(skel);
+}
+
+void test_timer_crash(void)
+{
+	if (test__start_subtest("array"))
+		test_timer_crash_mode(MODE_ARRAY);
+	if (test__start_subtest("hash"))
+		test_timer_crash_mode(MODE_HASH);
+}
diff --git a/tools/testing/selftests/bpf/progs/timer_crash.c b/tools/testing/selftests/bpf/progs/timer_crash.c
new file mode 100644
index 0000000000000..f8f7944e70dae
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/timer_crash.c
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <vmlinux.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_helpers.h>
+
+struct map_elem {
+	struct bpf_timer timer;
+	struct bpf_spin_lock lock;
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(max_entries, 1);
+	__type(key, int);
+	__type(value, struct map_elem);
+} amap SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__uint(max_entries, 1);
+	__type(key, int);
+	__type(value, struct map_elem);
+} hmap SEC(".maps");
+
+int pid = 0;
+int crash_map = 0; /* 0 for amap, 1 for hmap */
+
+SEC("fentry/do_nanosleep")
+int sys_enter(void *ctx)
+{
+	struct map_elem *e, value = {};
+	void *map = crash_map ? (void *)&hmap : (void *)&amap;
+
+	if (bpf_get_current_task_btf()->tgid != pid)
+		return 0;
+
+	*(void **)&value = (void *)0xdeadcaf3;
+
+	bpf_map_update_elem(map, &(int){0}, &value, 0);
+	/* For array map, doing bpf_map_update_elem will do a
+	 * check_and_free_timer_in_array, which will trigger the crash if timer
+	 * pointer was overwritten, for hmap we need to use bpf_timer_cancel.
+	 */
+	if (crash_map == 1) {
+		e = bpf_map_lookup_elem(map, &(int){0});
+		if (!e)
+			return 0;
+		bpf_timer_cancel(&e->timer);
+	}
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";
-- 
2.34.1

[PATCH AUTOSEL 5.15 22/23] selftest/vm: fix map_fixed_noreplace test failure

[Sasha Levin]

From: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>

[ Upstream commit f39c58008dee7ab5fc94c3f1995a21e886801df0 ]

On the latest RHEL the test fails due to executable mapped at 256MB
address

     # ./map_fixed_noreplace
    mmap() @ 0x10000000-0x10050000 p=0xffffffffffffffff result=File exists
    10000000-10010000 r-xp 00000000 fd:04 34905657                           /root/rpmbuild/BUILD/kernel-5.14.0-56.el9/linux-5.14.0-56.el9.ppc64le/tools/testing/selftests/vm/map_fixed_noreplace
    10010000-10020000 r--p 00000000 fd:04 34905657                           /root/rpmbuild/BUILD/kernel-5.14.0-56.el9/linux-5.14.0-56.el9.ppc64le/tools/testing/selftests/vm/map_fixed_noreplace
    10020000-10030000 rw-p 00010000 fd:04 34905657                           /root/rpmbuild/BUILD/kernel-5.14.0-56.el9/linux-5.14.0-56.el9.ppc64le/tools/testing/selftests/vm/map_fixed_noreplace
    10029b90000-10029bc0000 rw-p 00000000 00:00 0                            [heap]
    7fffbb510000-7fffbb750000 r-xp 00000000 fd:04 24534                      /usr/lib64/libc.so.6
    7fffbb750000-7fffbb760000 r--p 00230000 fd:04 24534                      /usr/lib64/libc.so.6
    7fffbb760000-7fffbb770000 rw-p 00240000 fd:04 24534                      /usr/lib64/libc.so.6
    7fffbb780000-7fffbb7a0000 r--p 00000000 00:00 0                          [vvar]
    7fffbb7a0000-7fffbb7b0000 r-xp 00000000 00:00 0                          [vdso]
    7fffbb7b0000-7fffbb800000 r-xp 00000000 fd:04 24514                      /usr/lib64/ld64.so.2
    7fffbb800000-7fffbb810000 r--p 00040000 fd:04 24514                      /usr/lib64/ld64.so.2
    7fffbb810000-7fffbb820000 rw-p 00050000 fd:04 24514                      /usr/lib64/ld64.so.2
    7fffd93f0000-7fffd9420000 rw-p 00000000 00:00 0                          [stack]
    Error: couldn't map the space we need for the test

Fix this by finding a free address using mmap instead of hardcoding
BASE_ADDRESS.

Link: https://lkml.kernel.org/r/20220217083417.373823-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Jann Horn <jannh@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 .../selftests/vm/map_fixed_noreplace.c        | 49 ++++++++++++++-----
 1 file changed, 37 insertions(+), 12 deletions(-)

diff --git a/tools/testing/selftests/vm/map_fixed_noreplace.c b/tools/testing/selftests/vm/map_fixed_noreplace.c
index d91bde5112686..eed44322d1a63 100644
--- a/tools/testing/selftests/vm/map_fixed_noreplace.c
+++ b/tools/testing/selftests/vm/map_fixed_noreplace.c
@@ -17,9 +17,6 @@
 #define MAP_FIXED_NOREPLACE 0x100000
 #endif
 
-#define BASE_ADDRESS	(256ul * 1024 * 1024)
-
-
 static void dump_maps(void)
 {
 	char cmd[32];
@@ -28,18 +25,46 @@ static void dump_maps(void)
 	system(cmd);
 }
 
+static unsigned long find_base_addr(unsigned long size)
+{
+	void *addr;
+	unsigned long flags;
+
+	flags = MAP_PRIVATE | MAP_ANONYMOUS;
+	addr = mmap(NULL, size, PROT_NONE, flags, -1, 0);
+	if (addr == MAP_FAILED) {
+		printf("Error: couldn't map the space we need for the test\n");
+		return 0;
+	}
+
+	if (munmap(addr, size) != 0) {
+		printf("Error: couldn't map the space we need for the test\n");
+		return 0;
+	}
+	return (unsigned long)addr;
+}
+
 int main(void)
 {
+	unsigned long base_addr;
 	unsigned long flags, addr, size, page_size;
 	char *p;
 
 	page_size = sysconf(_SC_PAGE_SIZE);
 
+	//let's find a base addr that is free before we start the tests
+	size = 5 * page_size;
+	base_addr = find_base_addr(size);
+	if (!base_addr) {
+		printf("Error: couldn't map the space we need for the test\n");
+		return 1;
+	}
+
 	flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_FIXED_NOREPLACE;
 
 	// Check we can map all the areas we need below
 	errno = 0;
-	addr = BASE_ADDRESS;
+	addr = base_addr;
 	size = 5 * page_size;
 	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
 
@@ -60,7 +85,7 @@ int main(void)
 	printf("unmap() successful\n");
 
 	errno = 0;
-	addr = BASE_ADDRESS + page_size;
+	addr = base_addr + page_size;
 	size = 3 * page_size;
 	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
 	printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);
@@ -80,7 +105,7 @@ int main(void)
 	 *     +4 |  free  | new
 	 */
 	errno = 0;
-	addr = BASE_ADDRESS;
+	addr = base_addr;
 	size = 5 * page_size;
 	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
 	printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);
@@ -101,7 +126,7 @@ int main(void)
 	 *     +4 |  free  |
 	 */
 	errno = 0;
-	addr = BASE_ADDRESS + (2 * page_size);
+	addr = base_addr + (2 * page_size);
 	size = page_size;
 	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
 	printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);
@@ -121,7 +146,7 @@ int main(void)
 	 *     +4 |  free  | new
 	 */
 	errno = 0;
-	addr = BASE_ADDRESS + (3 * page_size);
+	addr = base_addr + (3 * page_size);
 	size = 2 * page_size;
 	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
 	printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);
@@ -141,7 +166,7 @@ int main(void)
 	 *     +4 |  free  |
 	 */
 	errno = 0;
-	addr = BASE_ADDRESS;
+	addr = base_addr;
 	size = 2 * page_size;
 	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
 	printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);
@@ -161,7 +186,7 @@ int main(void)
 	 *     +4 |  free  |
 	 */
 	errno = 0;
-	addr = BASE_ADDRESS;
+	addr = base_addr;
 	size = page_size;
 	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
 	printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);
@@ -181,7 +206,7 @@ int main(void)
 	 *     +4 |  free  |  new
 	 */
 	errno = 0;
-	addr = BASE_ADDRESS + (4 * page_size);
+	addr = base_addr + (4 * page_size);
 	size = page_size;
 	p = mmap((void *)addr, size, PROT_NONE, flags, -1, 0);
 	printf("mmap() @ 0x%lx-0x%lx p=%p result=%m\n", addr, addr + size, p);
@@ -192,7 +217,7 @@ int main(void)
 		return 1;
 	}
 
-	addr = BASE_ADDRESS;
+	addr = base_addr;
 	size = 5 * page_size;
 	if (munmap((void *)addr, size) != 0) {
 		dump_maps();
-- 
2.34.1

[PATCH AUTOSEL 5.15 23/23] selftests/memfd: clean up mapping in mfd_fail_write

[Sasha Levin]

From: Mike Kravetz <mike.kravetz@oracle.com>

[ Upstream commit fda153c89af344d21df281009a9d046cf587ea0f ]

Running the memfd script ./run_hugetlbfs_test.sh will often end in error
as follows:

    memfd-hugetlb: CREATE
    memfd-hugetlb: BASIC
    memfd-hugetlb: SEAL-WRITE
    memfd-hugetlb: SEAL-FUTURE-WRITE
    memfd-hugetlb: SEAL-SHRINK
    fallocate(ALLOC) failed: No space left on device
    ./run_hugetlbfs_test.sh: line 60: 166855 Aborted                 (core dumped) ./memfd_test hugetlbfs
    opening: ./mnt/memfd
    fuse: DONE

If no hugetlb pages have been preallocated, run_hugetlbfs_test.sh will
allocate 'just enough' pages to run the test.  In the SEAL-FUTURE-WRITE
test the mfd_fail_write routine maps the file, but does not unmap.  As a
result, two hugetlb pages remain reserved for the mapping.  When the
fallocate call in the SEAL-SHRINK test attempts allocate all hugetlb
pages, it is short by the two reserved pages.

Fix by making sure to unmap in mfd_fail_write.

Link: https://lkml.kernel.org/r/20220219004340.56478-1-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/testing/selftests/memfd/memfd_test.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/testing/selftests/memfd/memfd_test.c b/tools/testing/selftests/memfd/memfd_test.c
index 192a2899bae8f..94df2692e6e4a 100644
--- a/tools/testing/selftests/memfd/memfd_test.c
+++ b/tools/testing/selftests/memfd/memfd_test.c
@@ -455,6 +455,7 @@ static void mfd_fail_write(int fd)
 			printf("mmap()+mprotect() didn't fail as expected\n");
 			abort();
 		}
+		munmap(p, mfd_def_size);
 	}
 
 	/* verify PUNCH_HOLE fails */
-- 
2.34.1