[ Upstream commit 1da6c4d9140cb7c13e87667dc4e1488d6c8fc10f ]
syzkaller was able to generate the following UAF in bpf:
BUG: KASAN: use-after-free in lookup_last fs/namei.c:2269 [inline]
BUG: KASAN: use-after-free in path_lookupat.isra.43+0x9f8/0xc00 fs/namei.c:2318
Read of size 1 at addr ffff8801c4865c47 by task syz-executor2/9423
CPU: 0 PID: 9423 Comm: syz-executor2 Not tainted 4.20.0-rc1-next-20181109+
#110
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x244/0x39d lib/dump_stack.c:113
print_address_description.cold.7+0x9/0x1ff mm/kasan/report.c:256
kasan_report_error mm/kasan/report.c:354 [inline]
kasan_report.cold.8+0x242/0x309 mm/kasan/report.c:412
__asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430
lookup_last fs/namei.c:2269 [inline]
path_lookupat.isra.43+0x9f8/0xc00 fs/namei.c:2318
filename_lookup+0x26a/0x520 fs/namei.c:2348
user_path_at_empty+0x40/0x50 fs/namei.c:2608
user_path include/linux/namei.h:62 [inline]
do_mount+0x180/0x1ff0 fs/namespace.c:2980
ksys_mount+0x12d/0x140 fs/namespace.c:3258
__do_sys_mount fs/namespace.c:3272 [inline]
__se_sys_mount fs/namespace.c:3269 [inline]
__x64_sys_mount+0xbe/0x150 fs/namespace.c:3269
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457569
Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff
ff 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fde6ed96c78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 0000000000457569
RDX: 0000000020000040 RSI: 0000000020000000 RDI: 0000000000000000
RBP: 000000000072bf00 R08: 0000000020000340 R09: 0000000000000000
R10: 0000000000200000 R11: 0000000000000246 R12: 00007fde6ed976d4
R13: 00000000004c2c24 R14: 00000000004d4990 R15: 00000000ffffffff
Allocated by task 9424:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
__do_kmalloc mm/slab.c:3722 [inline]
__kmalloc_track_caller+0x157/0x760 mm/slab.c:3737
kstrdup+0x39/0x70 mm/util.c:49
bpf_symlink+0x26/0x140 kernel/bpf/inode.c:356
vfs_symlink+0x37a/0x5d0 fs/namei.c:4127
do_symlinkat+0x242/0x2d0 fs/namei.c:4154
__do_sys_symlink fs/namei.c:4173 [inline]
__se_sys_symlink fs/namei.c:4171 [inline]
__x64_sys_symlink+0x59/0x80 fs/namei.c:4171
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Freed by task 9425:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
__cache_free mm/slab.c:3498 [inline]
kfree+0xcf/0x230 mm/slab.c:3817
bpf_evict_inode+0x11f/0x150 kernel/bpf/inode.c:565
evict+0x4b9/0x980 fs/inode.c:558
iput_final fs/inode.c:1550 [inline]
iput+0x674/0xa90 fs/inode.c:1576
do_unlinkat+0x733/0xa30 fs/namei.c:4069
__do_sys_unlink fs/namei.c:4110 [inline]
__se_sys_unlink fs/namei.c:4108 [inline]
__x64_sys_unlink+0x42/0x50 fs/namei.c:4108
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
In this scenario path lookup under RCU is racing with the final
unlink in case of symlinks. As Linus puts it in his analysis:
[...] We actually RCU-delay the inode freeing itself, but
when we do the final iput(), the "evict()" function is called
synchronously. Now, the simple fix would seem to just RCU-delay
the kfree() of the symlink data in bpf_evict_inode(). Maybe
that's the right thing to do. [...]
Al suggested to piggy-back on the ->destroy_inode() callback in
order to implement RCU deferral there which can then kfree() the
inode->i_link eventually right before putting inode back into
inode cache. By reusing free_inode_nonrcu() from there we can
avoid the need for our own inode cache and just reuse generic
one as we currently do.
And in-fact on top of all this we should just get rid of the
bpf_evict_inode() entirely. This means truncate_inode_pages_final()
and clear_inode() will then simply be called by the fs core via
evict(). Dropping the reference should really only be done when
inode is unhashed and nothing reachable anymore, so it's better
also moved into the final ->destroy_inode() callback.
Fixes: 0f98621bef5d ("bpf, inode: add support for symlinks and fix mtime/ctime")
Reported-by: syzbot+fb731ca573367b7f6564@syzkaller.appspotmail.com
Reported-by: syzbot+a13e5ead792d6df37818@syzkaller.appspotmail.com
Reported-by: syzbot+7a8ba368b47fdefca61e@syzkaller.appspotmail.com
Suggested-by: Al Viro <viro@zeniv.linux.org.uk>
Analyzed-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/lkml/0000000000006946d2057bbd0eef@google.com/T/
Signed-off-by: Sasha Levin (Microsoft) <sashal@kernel.org>
commit 0803278b0b4d8eeb2b461fb698785df65a725d9e upstream.
Syzkaller hit 'KASAN: use-after-free Write in sanitize_ptr_alu' bug.
Call trace:
dump_stack+0xbf/0x12e
print_address_description+0x6a/0x280
kasan_report+0x237/0x360
sanitize_ptr_alu+0x85a/0x8d0
adjust_ptr_min_max_vals+0x8f2/0x1ca0
adjust_reg_min_max_vals+0x8ed/0x22e0
do_check+0x1ca6/0x5d00
bpf_check+0x9ca/0x2570
bpf_prog_load+0xc91/0x1030
__se_sys_bpf+0x61e/0x1f00
do_syscall_64+0xc8/0x550
entry_SYSCALL_64_after_hwframe+0x49/0xbe
Fault injection trace:
kfree+0xea/0x290
free_func_state+0x4a/0x60
free_verifier_state+0x61/0xe0
push_stack+0x216/0x2f0 <- inject failslab
sanitize_ptr_alu+0x2b1/0x8d0
adjust_ptr_min_max_vals+0x8f2/0x1ca0
adjust_reg_min_max_vals+0x8ed/0x22e0
do_check+0x1ca6/0x5d00
bpf_check+0x9ca/0x2570
bpf_prog_load+0xc91/0x1030
__se_sys_bpf+0x61e/0x1f00
do_syscall_64+0xc8/0x550
entry_SYSCALL_64_after_hwframe+0x49/0xbe
When kzalloc() fails in push_stack(), free_verifier_state() will free
current verifier state. As push_stack() returns, dst_reg was restored
if ptr_is_dst_reg is false. However, as member of the cur_state,
dst_reg is also freed, and error occurs when dereferencing dst_reg.
Simply fix it by testing ret of push_stack() before restoring dst_reg.
Fixes: 979d63d50c0c ("bpf: prevent out of bounds speculation on pointer arithmetic")
Signed-off-by: Xu Yu <xuyu@linux.alibaba.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 7c0cdf0b3940f63d9777c3fcf250a2f83859ca54 ]
trie_delete_elem() was deleting an entry even though it was not matching
if the prefixlen was correct. This patch adds a check on matchlen.
Reproducer:
$ sudo bpftool map create /sys/fs/bpf/mylpm type lpm_trie key 8 value 1 entries 128 name mylpm flags 1
$ sudo bpftool map update pinned /sys/fs/bpf/mylpm key hex 10 00 00 00 aa bb cc dd value hex 01
$ sudo bpftool map dump pinned /sys/fs/bpf/mylpm
key: 10 00 00 00 aa bb cc dd value: 01
Found 1 element
$ sudo bpftool map delete pinned /sys/fs/bpf/mylpm key hex 10 00 00 00 ff ff ff ff
$ echo $?
0
$ sudo bpftool map dump pinned /sys/fs/bpf/mylpm
Found 0 elements
A similar reproducer is added in the selftests.
Without the patch:
$ sudo ./tools/testing/selftests/bpf/test_lpm_map
test_lpm_map: test_lpm_map.c:485: test_lpm_delete: Assertion `bpf_map_delete_elem(map_fd, key) == -1 && errno == ENOENT' failed.
Aborted
With the patch: test_lpm_map runs without errors.
Fixes: e454cf595853 ("bpf: Implement map_delete_elem for BPF_MAP_TYPE_LPM_TRIE")
Cc: Craig Gallek <kraig@google.com>
Signed-off-by: Alban Crequy <alban@kinvolk.io>
Acked-by: Craig Gallek <kraig@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 3defaf2f15b2bfd86c6664181ac009e91985f8ac ]
Lockdep warns about false positive:
[ 11.211460] ------------[ cut here ]------------
[ 11.211936] DEBUG_LOCKS_WARN_ON(depth <= 0)
[ 11.211985] WARNING: CPU: 0 PID: 141 at ../kernel/locking/lockdep.c:3592 lock_release+0x1ad/0x280
[ 11.213134] Modules linked in:
[ 11.214954] RIP: 0010:lock_release+0x1ad/0x280
[ 11.223508] Call Trace:
[ 11.223705] <IRQ>
[ 11.223874] ? __local_bh_enable+0x7a/0x80
[ 11.224199] up_read+0x1c/0xa0
[ 11.224446] do_up_read+0x12/0x20
[ 11.224713] irq_work_run_list+0x43/0x70
[ 11.225030] irq_work_run+0x26/0x50
[ 11.225310] smp_irq_work_interrupt+0x57/0x1f0
[ 11.225662] irq_work_interrupt+0xf/0x20
since rw_semaphore is released in a different task vs task that locked the sema.
It is expected behavior.
Fix the warning with up_read_non_owner() and rwsem_release() annotation.
Fixes: bae77c5eb5b2 ("bpf: enable stackmap with build_id in nmi context")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 7c4cd051add3d00bbff008a133c936c515eaa8fe ]
The map_lookup_elem used to not acquiring spinlock
in order to optimize the reader.
It was true until commit 557c0c6e7df8 ("bpf: convert stackmap to pre-allocation")
The syscall's map_lookup_elem(stackmap) calls bpf_stackmap_copy().
bpf_stackmap_copy() may find the elem no longer needed after the copy is done.
If that is the case, pcpu_freelist_push() saves this elem for reuse later.
This push requires a spinlock.
If a tracing bpf_prog got run in the middle of the syscall's
map_lookup_elem(stackmap) and this tracing bpf_prog is calling
bpf_get_stackid(stackmap) which also requires the same pcpu_freelist's
spinlock, it may end up with a dead lock situation as reported by
Eric Dumazet in https://patchwork.ozlabs.org/patch/1030266/
The situation is the same as the syscall's map_update_elem() which
needs to acquire the pcpu_freelist's spinlock and could race
with tracing bpf_prog. Hence, this patch fixes it by protecting
bpf_stackmap_copy() with this_cpu_inc(bpf_prog_active)
to prevent tracing bpf_prog from running.
A later syscall's map_lookup_elem commit f1a2e44a3aec ("bpf: add queue and stack maps")
also acquires a spinlock and races with tracing bpf_prog similarly.
Hence, this patch is forward looking and protects the majority
of the map lookups. bpf_map_offload_lookup_elem() is the exception
since it is for network bpf_prog only (i.e. never called by tracing
bpf_prog).
Fixes: 557c0c6e7df8 ("bpf: convert stackmap to pre-allocation")
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit a89fac57b5d080771efd4d71feaae19877cf68f0 ]
Lockdep warns about false positive:
[ 12.492084] 00000000e6b28347 (&head->lock){+...}, at: pcpu_freelist_push+0x2a/0x40
[ 12.492696] but this lock was taken by another, HARDIRQ-safe lock in the past:
[ 12.493275] (&rq->lock){-.-.}
[ 12.493276]
[ 12.493276]
[ 12.493276] and interrupts could create inverse lock ordering between them.
[ 12.493276]
[ 12.494435]
[ 12.494435] other info that might help us debug this:
[ 12.494979] Possible interrupt unsafe locking scenario:
[ 12.494979]
[ 12.495518] CPU0 CPU1
[ 12.495879] ---- ----
[ 12.496243] lock(&head->lock);
[ 12.496502] local_irq_disable();
[ 12.496969] lock(&rq->lock);
[ 12.497431] lock(&head->lock);
[ 12.497890] <Interrupt>
[ 12.498104] lock(&rq->lock);
[ 12.498368]
[ 12.498368] *** DEADLOCK ***
[ 12.498368]
[ 12.498837] 1 lock held by dd/276:
[ 12.499110] #0: 00000000c58cb2ee (rcu_read_lock){....}, at: trace_call_bpf+0x5e/0x240
[ 12.499747]
[ 12.499747] the shortest dependencies between 2nd lock and 1st lock:
[ 12.500389] -> (&rq->lock){-.-.} {
[ 12.500669] IN-HARDIRQ-W at:
[ 12.500934] _raw_spin_lock+0x2f/0x40
[ 12.501373] scheduler_tick+0x4c/0xf0
[ 12.501812] update_process_times+0x40/0x50
[ 12.502294] tick_periodic+0x27/0xb0
[ 12.502723] tick_handle_periodic+0x1f/0x60
[ 12.503203] timer_interrupt+0x11/0x20
[ 12.503651] __handle_irq_event_percpu+0x43/0x2c0
[ 12.504167] handle_irq_event_percpu+0x20/0x50
[ 12.504674] handle_irq_event+0x37/0x60
[ 12.505139] handle_level_irq+0xa7/0x120
[ 12.505601] handle_irq+0xa1/0x150
[ 12.506018] do_IRQ+0x77/0x140
[ 12.506411] ret_from_intr+0x0/0x1d
[ 12.506834] _raw_spin_unlock_irqrestore+0x53/0x60
[ 12.507362] __setup_irq+0x481/0x730
[ 12.507789] setup_irq+0x49/0x80
[ 12.508195] hpet_time_init+0x21/0x32
[ 12.508644] x86_late_time_init+0xb/0x16
[ 12.509106] start_kernel+0x390/0x42a
[ 12.509554] secondary_startup_64+0xa4/0xb0
[ 12.510034] IN-SOFTIRQ-W at:
[ 12.510305] _raw_spin_lock+0x2f/0x40
[ 12.510772] try_to_wake_up+0x1c7/0x4e0
[ 12.511220] swake_up_locked+0x20/0x40
[ 12.511657] swake_up_one+0x1a/0x30
[ 12.512070] rcu_process_callbacks+0xc5/0x650
[ 12.512553] __do_softirq+0xe6/0x47b
[ 12.512978] irq_exit+0xc3/0xd0
[ 12.513372] smp_apic_timer_interrupt+0xa9/0x250
[ 12.513876] apic_timer_interrupt+0xf/0x20
[ 12.514343] default_idle+0x1c/0x170
[ 12.514765] do_idle+0x199/0x240
[ 12.515159] cpu_startup_entry+0x19/0x20
[ 12.515614] start_kernel+0x422/0x42a
[ 12.516045] secondary_startup_64+0xa4/0xb0
[ 12.516521] INITIAL USE at:
[ 12.516774] _raw_spin_lock_irqsave+0x38/0x50
[ 12.517258] rq_attach_root+0x16/0xd0
[ 12.517685] sched_init+0x2f2/0x3eb
[ 12.518096] start_kernel+0x1fb/0x42a
[ 12.518525] secondary_startup_64+0xa4/0xb0
[ 12.518986] }
[ 12.519132] ... key at: [<ffffffff82b7bc28>] __key.71384+0x0/0x8
[ 12.519649] ... acquired at:
[ 12.519892] pcpu_freelist_pop+0x7b/0xd0
[ 12.520221] bpf_get_stackid+0x1d2/0x4d0
[ 12.520563] ___bpf_prog_run+0x8b4/0x11a0
[ 12.520887]
[ 12.521008] -> (&head->lock){+...} {
[ 12.521292] HARDIRQ-ON-W at:
[ 12.521539] _raw_spin_lock+0x2f/0x40
[ 12.521950] pcpu_freelist_push+0x2a/0x40
[ 12.522396] bpf_get_stackid+0x494/0x4d0
[ 12.522828] ___bpf_prog_run+0x8b4/0x11a0
[ 12.523296] INITIAL USE at:
[ 12.523537] _raw_spin_lock+0x2f/0x40
[ 12.523944] pcpu_freelist_populate+0xc0/0x120
[ 12.524417] htab_map_alloc+0x405/0x500
[ 12.524835] __do_sys_bpf+0x1a3/0x1a90
[ 12.525253] do_syscall_64+0x4a/0x180
[ 12.525659] entry_SYSCALL_64_after_hwframe+0x49/0xbe
[ 12.526167] }
[ 12.526311] ... key at: [<ffffffff838f7668>] __key.13130+0x0/0x8
[ 12.526812] ... acquired at:
[ 12.527047] __lock_acquire+0x521/0x1350
[ 12.527371] lock_acquire+0x98/0x190
[ 12.527680] _raw_spin_lock+0x2f/0x40
[ 12.527994] pcpu_freelist_push+0x2a/0x40
[ 12.528325] bpf_get_stackid+0x494/0x4d0
[ 12.528645] ___bpf_prog_run+0x8b4/0x11a0
[ 12.528970]
[ 12.529092]
[ 12.529092] stack backtrace:
[ 12.529444] CPU: 0 PID: 276 Comm: dd Not tainted 5.0.0-rc3-00018-g2fa53f892422 #475
[ 12.530043] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014
[ 12.530750] Call Trace:
[ 12.530948] dump_stack+0x5f/0x8b
[ 12.531248] check_usage_backwards+0x10c/0x120
[ 12.531598] ? ___bpf_prog_run+0x8b4/0x11a0
[ 12.531935] ? mark_lock+0x382/0x560
[ 12.532229] mark_lock+0x382/0x560
[ 12.532496] ? print_shortest_lock_dependencies+0x180/0x180
[ 12.532928] __lock_acquire+0x521/0x1350
[ 12.533271] ? find_get_entry+0x17f/0x2e0
[ 12.533586] ? find_get_entry+0x19c/0x2e0
[ 12.533902] ? lock_acquire+0x98/0x190
[ 12.534196] lock_acquire+0x98/0x190
[ 12.534482] ? pcpu_freelist_push+0x2a/0x40
[ 12.534810] _raw_spin_lock+0x2f/0x40
[ 12.535099] ? pcpu_freelist_push+0x2a/0x40
[ 12.535432] pcpu_freelist_push+0x2a/0x40
[ 12.535750] bpf_get_stackid+0x494/0x4d0
[ 12.536062] ___bpf_prog_run+0x8b4/0x11a0
It has been explained that is a false positive here:
https://lkml.org/lkml/2018/7/25/756
Recap:
- stackmap uses pcpu_freelist
- The lock in pcpu_freelist is a percpu lock
- stackmap is only used by tracing bpf_prog
- A tracing bpf_prog cannot be run if another bpf_prog
has already been running (ensured by the percpu bpf_prog_active counter).
Eric pointed out that this lockdep splats stops other
legit lockdep splats in selftests/bpf/test_progs.c.
Fix this by calling local_irq_save/restore for stackmap.
Another false positive had also been worked around by calling
local_irq_save in commit 89ad2fa3f043 ("bpf: fix lockdep splat").
That commit added unnecessary irq_save/restore to fast path of
bpf hash map. irqs are already disabled at that point, since htab
is holding per bucket spin_lock with irqsave.
Let's reduce overhead for htab by introducing __pcpu_freelist_push/pop
function w/o irqsave and convert pcpu_freelist_push/pop to irqsave
to be used elsewhere (right now only in stackmap).
It stops lockdep false positive in stackmap with a bit of acceptable overhead.
Fixes: 557c0c6e7df8 ("bpf: convert stackmap to pre-allocation")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 3612af783cf52c74a031a2f11b82247b2599d3cd upstream.
Marek reported that he saw an issue with the below snippet in that
timing measurements where off when loaded as unpriv while results
were reasonable when loaded as privileged:
[...]
uint64_t a = bpf_ktime_get_ns();
uint64_t b = bpf_ktime_get_ns();
uint64_t delta = b - a;
if ((int64_t)delta > 0) {
[...]
Turns out there is a bug where a corner case is missing in the fix
d3bd7413e0ca ("bpf: fix sanitation of alu op with pointer / scalar
type from different paths"), namely fixup_bpf_calls() only checks
whether aux has a non-zero alu_state, but it also needs to test for
the case of BPF_ALU_NON_POINTER since in both occasions we need to
skip the masking rewrite (as there is nothing to mask).
Fixes: d3bd7413e0ca ("bpf: fix sanitation of alu op with pointer / scalar type from different paths")
Reported-by: Marek Majkowski <marek@cloudflare.com>
Reported-by: Arthur Fabre <afabre@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/netdev/CAJPywTJqP34cK20iLM5YmUMz9KXQOdu1-+BZrGMAGgLuBWz7fg@mail.gmail.com/T/
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 4af396ae4836c4ecab61e975b8e61270c551894d ]
When returning BPF_STACK_BUILD_ID_IP from stack_map_get_build_id_offset,
make sure that build_id field is empty. Since we are using percpu
free list, there is a possibility that we might reuse some previous
bpf_stack_build_id with non-zero build_id.
Fixes: 615755a77b24 ("bpf: extend stackmap to save binary_build_id+offset instead of address")
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit 0b698005a9d11c0e91141ec11a2c4918a129f703 ]
Build-id length is not fixed to 20, it can be (`man ld` /--build-id):
* 128-bit (uuid)
* 160-bit (sha1)
* any length specified in ld --build-id=0xhexstring
To fix the issue of missing BPF_STACK_BUILD_ID_VALID for shorter build-ids,
assume that build-id is somewhere in the range of 1 .. 20.
Set the remaining bytes to zero.
v2:
* don't introduce new "len = min(BPF_BUILD_ID_SIZE, nhdr->n_descsz)",
we already know that nhdr->n_descsz <= BPF_BUILD_ID_SIZE if we enter
this 'if' condition
Fixes: 615755a77b24 ("bpf: extend stackmap to save binary_build_id+offset instead of address")
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
[ Upstream commit beaf3d1901f4ea46fbd5c9d857227d99751de469 ]
As Naresh reported, test_stacktrace_build_id() causes panic on i386 and
arm32 systems. This is caused by page_address() returns NULL in certain
cases.
This patch fixes this error by using kmap_atomic/kunmap_atomic instead
of page_address.
Fixes: 615755a77b24 (" bpf: extend stackmap to save binary_build_id+offset instead of address")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>