From 0abf854d7cbbb405e39e0f93d5c1da98dca24bc0 Mon Sep 17 00:00:00 2001 From: Anders Roxell Date: Tue, 10 Apr 2018 14:24:21 +0200 Subject: selftests: bpf: update .gitignore with missing generated files Signed-off-by: Anders Roxell Signed-off-by: Daniel Borkmann --- tools/testing/selftests/bpf/.gitignore | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/testing/selftests/bpf/.gitignore b/tools/testing/selftests/bpf/.gitignore index 9cf83f895d98..5e1ab2f0eb79 100644 --- a/tools/testing/selftests/bpf/.gitignore +++ b/tools/testing/selftests/bpf/.gitignore @@ -12,3 +12,6 @@ test_tcpbpf_user test_verifier_log feature test_libbpf_open +test_sock +test_sock_addr +urandom_read -- cgit v1.2.3-59-g8ed1b From 3a38bb98d9abdc3856f26b5ed4332803065cd7cf Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Tue, 10 Apr 2018 09:37:32 -0700 Subject: bpf/tracing: fix a deadlock in perf_event_detach_bpf_prog syzbot reported a possible deadlock in perf_event_detach_bpf_prog. The error details: ====================================================== WARNING: possible circular locking dependency detected 4.16.0-rc7+ #3 Not tainted ------------------------------------------------------ syz-executor7/24531 is trying to acquire lock: (bpf_event_mutex){+.+.}, at: [<000000008a849b07>] perf_event_detach_bpf_prog+0x92/0x3d0 kernel/trace/bpf_trace.c:854 but task is already holding lock: (&mm->mmap_sem){++++}, at: [<0000000038768f87>] vm_mmap_pgoff+0x198/0x280 mm/util.c:353 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&mm->mmap_sem){++++}: __might_fault+0x13a/0x1d0 mm/memory.c:4571 _copy_to_user+0x2c/0xc0 lib/usercopy.c:25 copy_to_user include/linux/uaccess.h:155 [inline] bpf_prog_array_copy_info+0xf2/0x1c0 kernel/bpf/core.c:1694 perf_event_query_prog_array+0x1c7/0x2c0 kernel/trace/bpf_trace.c:891 _perf_ioctl kernel/events/core.c:4750 [inline] perf_ioctl+0x3e1/0x1480 kernel/events/core.c:4770 vfs_ioctl fs/ioctl.c:46 [inline] do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 -> #0 (bpf_event_mutex){+.+.}: lock_acquire+0x1d5/0x580 kernel/locking/lockdep.c:3920 __mutex_lock_common kernel/locking/mutex.c:756 [inline] __mutex_lock+0x16f/0x1a80 kernel/locking/mutex.c:893 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 perf_event_detach_bpf_prog+0x92/0x3d0 kernel/trace/bpf_trace.c:854 perf_event_free_bpf_prog kernel/events/core.c:8147 [inline] _free_event+0xbdb/0x10f0 kernel/events/core.c:4116 put_event+0x24/0x30 kernel/events/core.c:4204 perf_mmap_close+0x60d/0x1010 kernel/events/core.c:5172 remove_vma+0xb4/0x1b0 mm/mmap.c:172 remove_vma_list mm/mmap.c:2490 [inline] do_munmap+0x82a/0xdf0 mm/mmap.c:2731 mmap_region+0x59e/0x15a0 mm/mmap.c:1646 do_mmap+0x6c0/0xe00 mm/mmap.c:1483 do_mmap_pgoff include/linux/mm.h:2223 [inline] vm_mmap_pgoff+0x1de/0x280 mm/util.c:355 SYSC_mmap_pgoff mm/mmap.c:1533 [inline] SyS_mmap_pgoff+0x462/0x5f0 mm/mmap.c:1491 SYSC_mmap arch/x86/kernel/sys_x86_64.c:100 [inline] SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:91 do_syscall_64+0x281/0x940 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x42/0xb7 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&mm->mmap_sem); lock(bpf_event_mutex); lock(&mm->mmap_sem); lock(bpf_event_mutex); *** DEADLOCK *** ====================================================== The bug is introduced by Commit f371b304f12e ("bpf/tracing: allow user space to query prog array on the same tp") where copy_to_user, which requires mm->mmap_sem, is called inside bpf_event_mutex lock. At the same time, during perf_event file descriptor close, mm->mmap_sem is held first and then subsequent perf_event_detach_bpf_prog needs bpf_event_mutex lock. Such a senario caused a deadlock. As suggested by Daniel, moving copy_to_user out of the bpf_event_mutex lock should fix the problem. Fixes: f371b304f12e ("bpf/tracing: allow user space to query prog array on the same tp") Reported-by: syzbot+dc5ca0e4c9bfafaf2bae@syzkaller.appspotmail.com Signed-off-by: Yonghong Song Signed-off-by: Daniel Borkmann --- include/linux/bpf.h | 4 ++-- kernel/bpf/core.c | 45 +++++++++++++++++++++++++++++---------------- kernel/trace/bpf_trace.c | 25 +++++++++++++++++++++---- 3 files changed, 52 insertions(+), 22 deletions(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 95a7abd0ee92..486e65e3db26 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -339,8 +339,8 @@ int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs, void bpf_prog_array_delete_safe(struct bpf_prog_array __rcu *progs, struct bpf_prog *old_prog); int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array, - __u32 __user *prog_ids, u32 request_cnt, - __u32 __user *prog_cnt); + u32 *prog_ids, u32 request_cnt, + u32 *prog_cnt); int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, struct bpf_prog *exclude_prog, struct bpf_prog *include_prog, diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index d315b393abdd..ba03ec39efb3 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -1572,13 +1572,32 @@ int bpf_prog_array_length(struct bpf_prog_array __rcu *progs) return cnt; } +static bool bpf_prog_array_copy_core(struct bpf_prog **prog, + u32 *prog_ids, + u32 request_cnt) +{ + int i = 0; + + for (; *prog; prog++) { + if (*prog == &dummy_bpf_prog.prog) + continue; + prog_ids[i] = (*prog)->aux->id; + if (++i == request_cnt) { + prog++; + break; + } + } + + return !!(*prog); +} + int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs, __u32 __user *prog_ids, u32 cnt) { struct bpf_prog **prog; unsigned long err = 0; - u32 i = 0, *ids; bool nospc; + u32 *ids; /* users of this function are doing: * cnt = bpf_prog_array_length(); @@ -1595,16 +1614,7 @@ int bpf_prog_array_copy_to_user(struct bpf_prog_array __rcu *progs, return -ENOMEM; rcu_read_lock(); prog = rcu_dereference(progs)->progs; - for (; *prog; prog++) { - if (*prog == &dummy_bpf_prog.prog) - continue; - ids[i] = (*prog)->aux->id; - if (++i == cnt) { - prog++; - break; - } - } - nospc = !!(*prog); + nospc = bpf_prog_array_copy_core(prog, ids, cnt); rcu_read_unlock(); err = copy_to_user(prog_ids, ids, cnt * sizeof(u32)); kfree(ids); @@ -1683,22 +1693,25 @@ int bpf_prog_array_copy(struct bpf_prog_array __rcu *old_array, } int bpf_prog_array_copy_info(struct bpf_prog_array __rcu *array, - __u32 __user *prog_ids, u32 request_cnt, - __u32 __user *prog_cnt) + u32 *prog_ids, u32 request_cnt, + u32 *prog_cnt) { + struct bpf_prog **prog; u32 cnt = 0; if (array) cnt = bpf_prog_array_length(array); - if (copy_to_user(prog_cnt, &cnt, sizeof(cnt))) - return -EFAULT; + *prog_cnt = cnt; /* return early if user requested only program count or nothing to copy */ if (!request_cnt || !cnt) return 0; - return bpf_prog_array_copy_to_user(array, prog_ids, request_cnt); + /* this function is called under trace/bpf_trace.c: bpf_event_mutex */ + prog = rcu_dereference_check(array, 1)->progs; + return bpf_prog_array_copy_core(prog, prog_ids, request_cnt) ? -ENOSPC + : 0; } static void bpf_prog_free_deferred(struct work_struct *work) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index d88e96d4e12c..56ba0f2a01db 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -977,6 +977,7 @@ int perf_event_query_prog_array(struct perf_event *event, void __user *info) { struct perf_event_query_bpf __user *uquery = info; struct perf_event_query_bpf query = {}; + u32 *ids, prog_cnt, ids_len; int ret; if (!capable(CAP_SYS_ADMIN)) @@ -985,16 +986,32 @@ int perf_event_query_prog_array(struct perf_event *event, void __user *info) return -EINVAL; if (copy_from_user(&query, uquery, sizeof(query))) return -EFAULT; - if (query.ids_len > BPF_TRACE_MAX_PROGS) + + ids_len = query.ids_len; + if (ids_len > BPF_TRACE_MAX_PROGS) return -E2BIG; + ids = kcalloc(ids_len, sizeof(u32), GFP_USER | __GFP_NOWARN); + if (!ids) + return -ENOMEM; + /* + * The above kcalloc returns ZERO_SIZE_PTR when ids_len = 0, which + * is required when user only wants to check for uquery->prog_cnt. + * There is no need to check for it since the case is handled + * gracefully in bpf_prog_array_copy_info. + */ mutex_lock(&bpf_event_mutex); ret = bpf_prog_array_copy_info(event->tp_event->prog_array, - uquery->ids, - query.ids_len, - &uquery->prog_cnt); + ids, + ids_len, + &prog_cnt); mutex_unlock(&bpf_event_mutex); + if (copy_to_user(&uquery->prog_cnt, &prog_cnt, sizeof(prog_cnt)) || + copy_to_user(uquery->ids, ids, ids_len * sizeof(u32))) + ret = -EFAULT; + + kfree(ids); return ret; } -- cgit v1.2.3-59-g8ed1b From 0a0a7e00a250c117f0c7ad8e1184abd98e7c098a Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Wed, 18 Apr 2018 10:49:12 -0700 Subject: tools/bpf: fix test_sock and test_sock_addr.sh failure The bpf selftests test_sock and test_sock_addr.sh failed in my test machine. The failure looks like: $ ./test_sock Test case: bind4 load with invalid access: src_ip6 .. [PASS] Test case: bind4 load with invalid access: mark .. [PASS] Test case: bind6 load with invalid access: src_ip4 .. [PASS] Test case: sock_create load with invalid access: src_port .. [PASS] Test case: sock_create load w/o expected_attach_type (compat mode) .. [FAIL] Test case: sock_create load w/ expected_attach_type .. [FAIL] Test case: attach type mismatch bind4 vs bind6 .. [FAIL] ... Summary: 4 PASSED, 12 FAILED $ ./test_sock_addr.sh Wait for testing IPv4/IPv6 to become available ..... ERROR: Timeout waiting for test IP to become available. In test_sock, bpf program loads failed due to hitting memlock limits. In test_sock_addr.sh, my test machine is a ipv6 only test box and using "ping" without specifying address family for an ipv6 address does not work. This patch fixed the issue by including header bpf_rlimit.h in test_sock.c and test_sock_addr.c, and specifying address family for ping command. Cc: Andrey Ignatov Signed-off-by: Yonghong Song Acked-by: Andrey Ignatov Signed-off-by: Daniel Borkmann --- tools/testing/selftests/bpf/test_sock.c | 1 + tools/testing/selftests/bpf/test_sock_addr.c | 1 + tools/testing/selftests/bpf/test_sock_addr.sh | 4 ++-- 3 files changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/bpf/test_sock.c b/tools/testing/selftests/bpf/test_sock.c index 73bb20cfb9b7..f4d99fabc56d 100644 --- a/tools/testing/selftests/bpf/test_sock.c +++ b/tools/testing/selftests/bpf/test_sock.c @@ -13,6 +13,7 @@ #include #include "cgroup_helpers.h" +#include "bpf_rlimit.h" #ifndef ARRAY_SIZE # define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0])) diff --git a/tools/testing/selftests/bpf/test_sock_addr.c b/tools/testing/selftests/bpf/test_sock_addr.c index d488f20926e8..2950f80ba7fb 100644 --- a/tools/testing/selftests/bpf/test_sock_addr.c +++ b/tools/testing/selftests/bpf/test_sock_addr.c @@ -15,6 +15,7 @@ #include #include "cgroup_helpers.h" +#include "bpf_rlimit.h" #define CG_PATH "/foo" #define CONNECT4_PROG_PATH "./connect4_prog.o" diff --git a/tools/testing/selftests/bpf/test_sock_addr.sh b/tools/testing/selftests/bpf/test_sock_addr.sh index c6e1dcf992c4..9832a875a828 100755 --- a/tools/testing/selftests/bpf/test_sock_addr.sh +++ b/tools/testing/selftests/bpf/test_sock_addr.sh @@ -4,7 +4,7 @@ set -eu ping_once() { - ping -q -c 1 -W 1 ${1%%/*} >/dev/null 2>&1 + ping -${1} -q -c 1 -W 1 ${2%%/*} >/dev/null 2>&1 } wait_for_ip() @@ -13,7 +13,7 @@ wait_for_ip() echo -n "Wait for testing IPv4/IPv6 to become available " for _i in $(seq ${MAX_PING_TRIES}); do echo -n "." - if ping_once ${TEST_IPv4} && ping_once ${TEST_IPv6}; then + if ping_once 4 ${TEST_IPv4} && ping_once 6 ${TEST_IPv6}; then echo " OK" return fi -- cgit v1.2.3-59-g8ed1b From 6ab690aa439803347743c0d899ac422774fdd5e7 Mon Sep 17 00:00:00 2001 From: Jann Horn Date: Fri, 20 Apr 2018 18:16:30 +0200 Subject: bpf: sockmap remove dead check Remove dead code that bails on `attr->value_size > KMALLOC_MAX_SIZE` - the previous check already bails on `attr->value_size != 4`. Signed-off-by: Jann Horn Signed-off-by: Daniel Borkmann --- kernel/bpf/sockmap.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index 8dd9210d7db7..a3b21385e947 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -1442,9 +1442,6 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr) attr->value_size != 4 || attr->map_flags & ~SOCK_CREATE_FLAG_MASK) return ERR_PTR(-EINVAL); - if (attr->value_size > KMALLOC_MAX_SIZE) - return ERR_PTR(-E2BIG); - err = bpf_tcp_ulp_register(); if (err && err != -EEXIST) return ERR_PTR(err); -- cgit v1.2.3-59-g8ed1b