- Linux-kselftest-mirror - lists.linaro.org

[PATCH] selftests/tracing: Add basic test for trace_marker_raw file

by Steven Rostedt

From: Steven Rostedt <rostedt(a)goodmis.org> Commit 64cf7d058a00 ("tracing: Have trace_marker use per-cpu data to read user space") made an update that fixed both trace_marker and trace_marker_raw. But the small difference made to trace_marker_raw had a blatant bug in it that any basic testing would have uncovered. Unfortunately, the self tests have tests for trace_marker but nothing for trace_marker_raw which allowed the bug to get upstream. Add basic selftests to test trace_marker_raw so that this doesn't happen again. Signed-off-by: Steven Rostedt (Google) <rostedt(a)goodmis.org> --- .../ftrace/test.d/00basic/trace_marker_raw.tc | 107 ++++++++++++++++++ 1 file changed, 107 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc diff --git a/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc new file mode 100644 index 000000000000..7daf7292209e --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/00basic/trace_marker_raw.tc @@ -0,0 +1,107 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: Basic tests on writing to trace_marker_raw +# requires: trace_marker_raw +# flags: instance + +is_little_endian() { + if lscpu | grep -q 'Little Endian'; then + echo 1; + else + echo 0; + fi +} + +little=`is_little_endian` + +make_str() { + id=$1 + cnt=$2 + + if [ $little -eq 1 ]; then + val=`printf "\\%03o\\%03o\\%03o\\%03o" \ + $(($id & 0xff)) \ + $((($id >> 8) & 0xff)) \ + $((($id >> 16) & 0xff)) \ + $((($id >> 24) & 0xff))` + else + val=`printf "\\%03o\\%03o\\%03o\\%03o" \ + $((($id >> 24) & 0xff)) \ + $((($id >> 16) & 0xff)) \ + $((($id >> 8) & 0xff)) \ + $(($id & 0xff))` + fi + + data=`printf -- 'X%.0s' $(seq $cnt)` + + printf "${val}${data}" +} + +write_buffer() { + id=$1 + size=$2 + + # write the string into the raw marker + make_str $id $size > trace_marker_raw +} + + +test_multiple_writes() { + + # Write a bunch of data where the id is the count of + # data to write + for i in `seq 1 10` `seq 101 110` `seq 1001 1010`; do + write_buffer $i $i + done + + # add a little buffer + echo stop > trace_marker + + # Check to make sure the number of entries is the id (rounded up by 4) + awk '/.*: # [0-9a-f]* / { + print; + cnt = -1; + for (i = 0; i < NF; i++) { + # The counter is after the "#" marker + if ( $i == "#" ) { + i++; + cnt = strtonum("0x" $i); + num = NF - (i + 1); + # The number of items is always rounded up by 4 + cnt2 = int((cnt + 3) / 4) * 4; + if (cnt2 != num) { + exit 1; + } + break; + } + } + } + // { if (NR > 30) { exit 0; } } ' trace_pipe; +} + + +get_buffer_data_size() { + sed -ne 's/^.*data.*size:$[0-9][0-9]*$.*/\1/p' events/header_page +} + +test_buffer() { + + # The id must be four bytes, test that 3 bytes fails a write + if echo -n abc > ./trace_marker_raw ; then + echo "Too small of write expected to fail but did not" + exit_fail + fi + + size=`get_buffer_data_size` + echo size = $size + + # Now add a little more than what it can handle + + if write_buffer 0xdeadbeef $size ; then + echo "Too big of write expected to fail but did not" + exit_fail + fi +} + +test_buffer +test_multiple_writes -- 2.51.0

1 day, 4 hours

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[PATCH v6 0/2] KVM: guest_memfd: use write for population

by Kalyazin, Nikita

[ based on kvm/next ] Implement guest_memfd population via the write syscall. This is useful in non-CoCo use cases where the host can access guest memory. Even though the same can also be achieved via userspace mapping and memcpying from userspace, write provides a more performant option because it does not need to set page tables and it does not cause a page fault for every page like memcpy would. Note that memcpy cannot be accelerated via MADV_POPULATE_WRITE as it is not supported by guest_memfd and relies on GUP. Populating 512MiB of guest_memfd on a x86 machine: - via memcpy: 436 ms - via write: 202 ms (-54%) The write syscall support is conditional on kvm_gmem_supports_mmap. When in-place shared/private conversion is supported, write should only be allowed on shared pages. v6: - Make write support conditional on mmap support instead of relying on the up-to-date flag to decide whether writing to a page is allowed - James: Remove depenendencies on folio_test_large - James: Remove page alignment restriction - James: Formatting fixes v5: - https://lore.kernel.org/kvm/20250902111951.58315-1-kalyazin@amazon.com/ - Replace the call to the unexported filemap_remove_folio with zeroing the bytes that could not be copied - Fix checkpatch findings v4: - https://lore.kernel.org/kvm/20250828153049.3922-1-kalyazin@amazon.com - Switch from implementing the write callback to write_iter - Remove conditional compilation v3: - https://lore.kernel.org/kvm/20250303130838.28812-1-kalyazin@amazon.com - David/Mike D: Only compile support for the write syscall if CONFIG_KVM_GMEM_SHARED_MEM (now gone) is enabled. v2: - https://lore.kernel.org/kvm/20241129123929.64790-1-kalyazin@amazon.com - Switch from an ioctl to the write syscall to implement population v1: - https://lore.kernel.org/kvm/20241024095429.54052-1-kalyazin@amazon.com Nikita Kalyazin (2): KVM: guest_memfd: add generic population via write KVM: selftests: update guest_memfd write tests .../testing/selftests/kvm/guest_memfd_test.c | 51 ++++++++++++++++--- virt/kvm/guest_memfd.c | 49 ++++++++++++++++++ 2 files changed, 94 insertions(+), 6 deletions(-) base-commit: 6b36119b94d0b2bb8cea9d512017efafd461d6ac -- 2.50.1

1 day, 4 hours

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[PATCH] kselftest/arm64: Align zt-test register dumps

by Mark Rutland

The zt-test output is awkward to read, as the 'Expected' value isn't dumped on its own line and isn't aligned with the 'Got' value beneath. For example: Mismatch: PID=5281, iteration=3270249 Expected [00a1146901a1146902a1146903a1146904a1146905a1146906a1146907a1146908a1146909a114690aa114690ba114690ca114690da114690ea114690fa11469] Got [00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000] SVCR: 2 Add a newline, matching the other FPSIMD/SVE/SME tests, so that we get output that can be read more easily: Mismatch: PID=5281, iteration=3270249 Expected [00a1146901a1146902a1146903a1146904a1146905a1146906a1146907a1146908a1146909a114690aa114690ba114690ca114690da114690ea114690fa11469] Got [00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000] SVCR: 2 Admittedly this isn't all that important when the 'Got' value is all zeroes, but otherwise this would be a major help for identifying which portion of the 'Got' value is not as expected. Signed-off-by: Mark Rutland <mark.rutland(a)arm.com> Cc: Catalin Marinas <catalin.marinas(a)arm.com> Cc: Mark Brown <broonie(a)kernel.org> Cc: Shuah Khan <shuah(a)kernel.org> Cc: Will Deacon <will(a)kernel.org> Cc: linux-arm-kernel(a)lists.infradead.org Cc: linux-kselftest(a)vger.kernel.org --- tools/testing/selftests/arm64/fp/zt-test.S | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/arm64/fp/zt-test.S b/tools/testing/selftests/arm64/fp/zt-test.S index 38080f3c32804..a8df057716707 100644 --- a/tools/testing/selftests/arm64/fp/zt-test.S +++ b/tools/testing/selftests/arm64/fp/zt-test.S @@ -276,7 +276,7 @@ function barf bl putdec puts ", iteration=" mov x0, x22 - bl putdec + bl putdecn puts "\tExpected [" mov x0, x10 mov x1, x12 -- 2.30.2

1 day, 5 hours

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[PATCH net v3 0/3] mptcp: Fix conflicts between MPTCP and sockmap

by Jiayuan Chen

Overall, we encountered a warning [1] that can be triggered by running the selftest I provided. MPTCP creates subflows for data transmission between two endpoints. However, BPF can use sockops to perform additional operations when TCP completes the three-way handshake. The issue arose because we used sockmap in sockops, which replaces sk->sk_prot and some handlers. Since subflows also have their own specialized handlers, this creates a conflict and leads to traffic failure. Therefore, we need to reject operations targeting subflows. This patchset simply prevents the combination of subflows and sockmap without changing any functionality. A complete integration of MPTCP and sockmap would require more effort, for example, we would need to retrieve the parent socket from subflows in sockmap and implement handlers like read_skb. If maintainers don't object, we can further improve this in subsequent work. [1] truncated warning: [ 18.234652] ------------[ cut here ]------------ [ 18.234664] WARNING: CPU: 1 PID: 388 at net/mptcp/protocol.c:68 mptcp_stream_accept+0x34c/0x380 [ 18.234726] Modules linked in: [ 18.234755] RIP: 0010:mptcp_stream_accept+0x34c/0x380 [ 18.234762] RSP: 0018:ffffc90000cf3cf8 EFLAGS: 00010202 [ 18.234800] PKRU: 55555554 [ 18.234806] Call Trace: [ 18.234810] <TASK> [ 18.234837] do_accept+0xeb/0x190 [ 18.234861] ? __x64_sys_pselect6+0x61/0x80 [ 18.234898] ? _raw_spin_unlock+0x12/0x30 [ 18.234915] ? alloc_fd+0x11e/0x190 [ 18.234925] __sys_accept4+0x8c/0x100 [ 18.234930] __x64_sys_accept+0x1f/0x30 [ 18.234933] x64_sys_call+0x202f/0x20f0 [ 18.234966] do_syscall_64+0x72/0x9a0 [ 18.234979] ? switch_fpu_return+0x60/0xf0 [ 18.234993] ? irqentry_exit_to_user_mode+0xdb/0x1e0 [ 18.235002] ? irqentry_exit+0x3f/0x50 [ 18.235005] ? clear_bhb_loop+0x50/0xa0 [ 18.235022] ? clear_bhb_loop+0x50/0xa0 [ 18.235025] ? clear_bhb_loop+0x50/0xa0 [ 18.235028] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 18.235066] </TASK> [ 18.235109] ---[ end trace 0000000000000000 ]--- --- v2: https://lore.kernel.org/bpf/20251020060503.325369-1-jiayuan.chen@linux.dev/… Some advice suggested by Jakub Sitnicki v1: https://lore.kernel.org/mptcp/a0a2b87119a06c5ffaa51427a0964a05534fe6f1@linu… Some advice from Matthieu Baerts. Jiayuan Chen (3): net,mptcp: fix proto fallback detection with BPF sockmap bpf,sockmap: disallow MPTCP sockets from sockmap selftests/bpf: Add mptcp test with sockmap net/core/sock_map.c | 27 ++++ net/mptcp/protocol.c | 9 +- .../testing/selftests/bpf/prog_tests/mptcp.c | 150 ++++++++++++++++++ .../selftests/bpf/progs/mptcp_sockmap.c | 43 +++++ 4 files changed, 227 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/mptcp_sockmap.c -- 2.43.0

1 day, 5 hours

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[PATCH] selftests/timers: Skip some posix_timers tests on kernels < 6.13

by Wake Liu

Several tests in the posix_timers selftest fail on kernels older than 6.13. These tests check for timer behavior related to SIG_IGN, which was refactored in the 6.13 kernel cycle, notably by commit caf77435dd8a ("signal: Handle ignored signals in do_sigaction(action != SIG_IGN)"). To ensure the selftests pass on older, stable kernels, gate the affected tests with a ksft_min_kernel_version(6, 13) check. Signed-off-by: Wake Liu <wakel(a)google.com> --- tools/testing/selftests/timers/posix_timers.c | 21 +++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/tools/testing/selftests/timers/posix_timers.c b/tools/testing/selftests/timers/posix_timers.c index f0eceb0faf34..f228e51f8b58 100644 --- a/tools/testing/selftests/timers/posix_timers.c +++ b/tools/testing/selftests/timers/posix_timers.c @@ -256,6 +256,11 @@ static void *ignore_thread(void *arg) static void check_sig_ign(int thread) { + if (!ksft_min_kernel_version(6, 13)) { + // see caf77435dd8a + ksft_test_result_skip("Depends on refactor of posix timers in 6.13\n"); + return; + } struct tmrsig tsig = { }; struct itimerspec its; unsigned int tid = 0; @@ -342,6 +347,10 @@ static void check_sig_ign(int thread) static void check_rearm(void) { + if (!ksft_min_kernel_version(6, 13)) { + ksft_test_result_skip("Depends on refactor of posix timers in 6.13\n"); + return; + } struct tmrsig tsig = { }; struct itimerspec its; struct sigaction sa; @@ -398,6 +407,10 @@ static void check_rearm(void) static void check_delete(void) { + if (!ksft_min_kernel_version(6, 13)) { + ksft_test_result_skip("Depends on refactor of posix timers in 6.13\n"); + return; + } struct tmrsig tsig = { }; struct itimerspec its; struct sigaction sa; @@ -455,6 +468,10 @@ static inline int64_t calcdiff_ns(struct timespec t1, struct timespec t2) static void check_sigev_none(int which, const char *name) { + if (!ksft_min_kernel_version(6, 13)) { + ksft_test_result_skip("Depends on refactor of posix timers in 6.13\n"); + return; + } struct timespec start, now; struct itimerspec its; struct sigevent sev; @@ -493,6 +510,10 @@ static void check_sigev_none(int which, const char *name) static void check_gettime(int which, const char *name) { + if (!ksft_min_kernel_version(6, 13)) { + ksft_test_result_skip("Depends on refactor of posix timers in 6.13\n"); + return; + } struct itimerspec its, prev; struct timespec start, now; struct sigevent sev; -- 2.50.1.703.g449372360f-goog

1 day, 9 hours

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[PATCH bpf-next 0/4] selftests/bpf: convert test_tc_edt.sh into test_progs

by Alexis Lothoré (eBPF Foundation)

Hello, this is yet another conversion series, this time tackling the test_tc_edt.sh. This one was at the bottom of our list due to the fact that it is based on some bandwith measurement (and so, increasing the risk to make it flaky in CI), but here is an attempt anyway, as it also showcases a nice example of BPF-based rate shaping. The converted test roughly follows the original script logic, with two veths in two namespaces, a TCP connection between a client and a server, and the client pushing as much data as possible during a specific period. We then compute the effective data rate, shaped by the eBPF program, by reading the RX interface stats, and compare it to the target rate. The test passes if the measured rate is within a defined error margin. There are two knobs driving the robustness of the test in CI: - the test duration (the higher, the more precise is the effective rate) - the tolerated error margin The original test was configured with a 20s duration and a 1% error margin. The new test is configured with a 2s duration and a 2% error margin, to: - make the duration tolerable in CI - while keeping enough margin for rate measure fluctuations depending on the CI machines load This has been run multiple times locally to ensure that those values are sane, and once in CI before sending the series, but I suggest to let it live a few days in CI to see how it really behaves. Signed-off-by: Alexis Lothoré (eBPF Foundation) <alexis.lothore(a)bootlin.com> --- Alexis Lothoré (eBPF Foundation) (4): selftests/bpf: rename test_tc_edt.bpf.c section to expose program type selftests/bpf: integrate test_tc_edt into test_progs selftests/bpf: remove test_tc_edt.sh selftests/bpf: do not hardcode target rate in test_tc_edt BPF program tools/testing/selftests/bpf/Makefile | 2 - .../testing/selftests/bpf/prog_tests/test_tc_edt.c | 274 +++++++++++++++++++++ tools/testing/selftests/bpf/progs/test_tc_edt.c | 9 +- tools/testing/selftests/bpf/test_tc_edt.sh | 100 -------- 4 files changed, 279 insertions(+), 106 deletions(-) --- base-commit: 1e2d874b04ba46a3b9fe6697097aa437641f4339 change-id: 20251030-tc_edt-3ea8e8d3d14e Best regards, -- Alexis Lothoré, Bootlin Embedded Linux and Kernel engineering https://bootlin.com

1 day, 12 hours

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[PATCH 0/3] introduce VM_MAYBE_GUARD and make it sticky

by Lorenzo Stoakes

Currently, guard regions are not visible to users except through /proc/$pid/pagemap, with no explicit visibility at the VMA level. This makes the feature less useful, as it isn't entirely apparent which VMAs may have these entries present, especially when performing actions which walk through memory regions such as those performed by CRIU. This series addresses this issue by introducing the VM_MAYBE_GUARD flag which fulfils this role, updating the smaps logic to display an entry for these. The semantics of this flag are that a guard region MAY be present if set (we cannot be sure, as we can't efficiently track whether an MADV_GUARD_REMOVE finally removes all the guard regions in a VMA) - but if not set the VMA definitely does NOT have any guard regions present. It's problematic to establish this flag without further action, because that means that VMAs with guard regions in them become non-mergeable with adjacent VMAs for no especially good reason. To work around this, this series also introduces the concept of 'sticky' VMA flags - that is flags which: a. if set in one VMA and not in another still permit those VMAs to be merged (if otherwise compatible). b. When they are merged, the resultant VMA must have the flag set. The VMA logic is updated to propagate these flags correctly. Additionally, VM_MAYBE_GUARD being an explicit VMA flag allows us to solve an issue with file-backed guard regions - previously these established an anon_vma object for file-backed mappings solely to have vma_needs_copy() correctly propagate guard region mappings to child processes. We introduce a new flag alias VM_COPY_ON_FORK (which currently only specifies VM_MAYBE_GUARD) and update vma_needs_copy() to check explicitly for this flag and to copy page tables if it is present, which resolves this issue. Finally we introduce extensive VMA userland tests to assert that the sticky VMA logic behaves correctly as well as guard region self tests to assert that smaps visibility is correctly implemented. Lorenzo Stoakes (3): mm: introduce VM_MAYBE_GUARD and make visible for guard regions mm: implement sticky, copy on fork VMA flags selftests/mm/guard-regions: add smaps visibility test Documentation/filesystems/proc.rst | 1 + fs/proc/task_mmu.c | 1 + include/linux/mm.h | 33 ++++++ include/trace/events/mmflags.h | 1 + mm/madvise.c | 22 ++-- mm/memory.c | 3 + mm/vma.c | 22 ++-- tools/testing/selftests/mm/guard-regions.c | 120 +++++++++++++++++++++ tools/testing/selftests/mm/vm_util.c | 5 + tools/testing/selftests/mm/vm_util.h | 1 + tools/testing/vma/vma.c | 89 +++++++++++++-- tools/testing/vma/vma_internal.h | 33 ++++++ 12 files changed, 303 insertions(+), 28 deletions(-) -- 2.51.0

1 day, 12 hours

5
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[PATCH bpf-next v3 0/2] bpf: Skip bounds adjustment for conditional jumps on same scalar register

by KaFai Wan

This small patchset is about avoid verifier bug warning when conditional jumps on same register when the register holds a scalar with range. v3: - Enhance is_scalar_branch_taken() to handle scalar case. (Eduard) - Update the selftest to cover all conditional jump opcodes. (Eduard) v2: https://lore.kernel.org/bpf/20251025053017.2308823-1-kafai.wan@linux.dev/ - Enhance is_branch_taken() and is_scalar_branch_taken() to handle branch direction computation for same register. (Eduard and Alexei) - Update the selftest. v1: https://lore.kernel.org/bpf/20251022164457.1203756-1-kafai.wan@linux.dev/ --- KaFai Wan (2): bpf: Skip bounds adjustment for conditional jumps on same scalar register selftests/bpf: Add test for conditional jumps on same scalar register kernel/bpf/verifier.c | 33 ++++ .../selftests/bpf/progs/verifier_bounds.c | 154 ++++++++++++++++++ 2 files changed, 187 insertions(+) -- 2.43.0

1 day, 15 hours

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[PATCH v12] exec: Fix dead-lock in de_thread with ptrace_attach

by Bernd Edlinger

This introduces signal->exec_bprm, which is used to fix the case when at least one of the sibling threads is traced, and therefore the trace process may dead-lock in ptrace_attach, but de_thread will need to wait for the tracer to continue execution. The solution is to detect this situation and allow ptrace_attach to continue by temporarily releasing the cred_guard_mutex, while de_thread() is still waiting for traced zombies to be eventually released by the tracer. In the case of the thread group leader we only have to wait for the thread to become a zombie, which may also need co-operation from the tracer due to PTRACE_O_TRACEEXIT. When a tracer wants to ptrace_attach a task that already is in execve, we simply retry the ptrace_may_access check while temporarily installing the new credentials and dumpability which are about to be used after execve completes. If the ptrace_attach happens on a thread that is a sibling-thread of the thread doing execve, it is sufficient to check against the old credentials, as this thread will be waited for, before the new credentials are installed. Other threads die quickly since the cred_guard_mutex is released, but a deadly signal is already pending. In case the mutex_lock_killable misses the signal, the non-zero current->signal->exec_bprm makes sure they release the mutex immediately and return with -ERESTARTNOINTR. This means there is no API change, unlike the previous version of this patch which was discussed here: https://lore.kernel.org/lkml/b6537ae6-31b1-5c50-f32b-8b8332ace882@hotmail.d… See tools/testing/selftests/ptrace/vmaccess.c for a test case that gets fixed by this change. Note that since the test case was originally designed to test the ptrace_attach returning an error in this situation, the test expectation needed to be adjusted, to allow the API to succeed at the first attempt. Signed-off-by: Bernd Edlinger <bernd.edlinger(a)hotmail.de> --- fs/exec.c | 69 ++++++++++++++++------- fs/proc/base.c | 6 ++ include/linux/cred.h | 1 + include/linux/sched/signal.h | 18 ++++++ kernel/cred.c | 28 +++++++-- kernel/ptrace.c | 32 +++++++++++ kernel/seccomp.c | 12 +++- tools/testing/selftests/ptrace/vmaccess.c | 23 +++++--- 8 files changed, 155 insertions(+), 34 deletions(-) v10: Changes to previous version, make the PTRACE_ATTACH retun -EAGAIN, instead of execve return -ERESTARTSYS. Added some lessions learned to the description. v11: Check old and new credentials in PTRACE_ATTACH again without changing the API. Note: I got actually one response from an automatic checker to the v11 patch, https://lore.kernel.org/lkml/202107121344.wu68hEPF-lkp@intel.com/ which is complaining about: >> kernel/ptrace.c:425:26: sparse: sparse: incorrect type in assignment (different address spaces) @@ expected struct cred const *old_cred @@ got struct cred const [noderef] __rcu *real_cred @@ 417 struct linux_binprm *bprm = task->signal->exec_bprm; 418 const struct cred *old_cred; 419 struct mm_struct *old_mm; 420 421 retval = down_write_killable(&task->signal->exec_update_lock); 422 if (retval) 423 goto unlock_creds; 424 task_lock(task); > 425 old_cred = task->real_cred; v12: Essentially identical to v11. - Fixed a minor merge conflict in linux v5.17, and fixed the above mentioned nit by adding __rcu to the declaration. - re-tested the patch with all linux versions from v5.11 to v6.6 v10 was an alternative approach which did imply an API change. But I would prefer to avoid such an API change. The difficult part is getting the right dumpability flags assigned before de_thread starts, hope you like this version. If not, the v10 is of course also acceptable. Thanks Bernd. diff --git a/fs/exec.c b/fs/exec.c index 2f2b0acec4f0..902d3b230485 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1041,11 +1041,13 @@ static int exec_mmap(struct mm_struct *mm) return 0; } -static int de_thread(struct task_struct *tsk) +static int de_thread(struct task_struct *tsk, struct linux_binprm *bprm) { struct signal_struct *sig = tsk->signal; struct sighand_struct *oldsighand = tsk->sighand; spinlock_t *lock = &oldsighand->siglock; + struct task_struct *t = tsk; + bool unsafe_execve_in_progress = false; if (thread_group_empty(tsk)) goto no_thread_group; @@ -1068,6 +1070,19 @@ static int de_thread(struct task_struct *tsk) if (!thread_group_leader(tsk)) sig->notify_count--; + while_each_thread(tsk, t) { + if (unlikely(t->ptrace) + && (t != tsk->group_leader || !t->exit_state)) + unsafe_execve_in_progress = true; + } + + if (unlikely(unsafe_execve_in_progress)) { + spin_unlock_irq(lock); + sig->exec_bprm = bprm; + mutex_unlock(&sig->cred_guard_mutex); + spin_lock_irq(lock); + } + while (sig->notify_count) { __set_current_state(TASK_KILLABLE); spin_unlock_irq(lock); @@ -1158,6 +1173,11 @@ static int de_thread(struct task_struct *tsk) release_task(leader); } + if (unlikely(unsafe_execve_in_progress)) { + mutex_lock(&sig->cred_guard_mutex); + sig->exec_bprm = NULL; + } + sig->group_exec_task = NULL; sig->notify_count = 0; @@ -1169,6 +1189,11 @@ static int de_thread(struct task_struct *tsk) return 0; killed: + if (unlikely(unsafe_execve_in_progress)) { + mutex_lock(&sig->cred_guard_mutex); + sig->exec_bprm = NULL; + } + /* protects against exit_notify() and __exit_signal() */ read_lock(&tasklist_lock); sig->group_exec_task = NULL; @@ -1253,6 +1278,24 @@ int begin_new_exec(struct linux_binprm * bprm) if (retval) return retval; + /* If the binary is not readable then enforce mm->dumpable=0 */ + would_dump(bprm, bprm->file); + if (bprm->have_execfd) + would_dump(bprm, bprm->executable); + + /* + * Figure out dumpability. Note that this checking only of current + * is wrong, but userspace depends on it. This should be testing + * bprm->secureexec instead. + */ + if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP || + is_dumpability_changed(current_cred(), bprm->cred) || + !(uid_eq(current_euid(), current_uid()) && + gid_eq(current_egid(), current_gid()))) + set_dumpable(bprm->mm, suid_dumpable); + else + set_dumpable(bprm->mm, SUID_DUMP_USER); + /* * Ensure all future errors are fatal. */ @@ -1261,7 +1304,7 @@ int begin_new_exec(struct linux_binprm * bprm) /* * Make this the only thread in the thread group. */ - retval = de_thread(me); + retval = de_thread(me, bprm); if (retval) goto out; @@ -1284,11 +1327,6 @@ int begin_new_exec(struct linux_binprm * bprm) if (retval) goto out; - /* If the binary is not readable then enforce mm->dumpable=0 */ - would_dump(bprm, bprm->file); - if (bprm->have_execfd) - would_dump(bprm, bprm->executable); - /* * Release all of the old mmap stuff */ @@ -1350,18 +1388,6 @@ int begin_new_exec(struct linux_binprm * bprm) me->sas_ss_sp = me->sas_ss_size = 0; - /* - * Figure out dumpability. Note that this checking only of current - * is wrong, but userspace depends on it. This should be testing - * bprm->secureexec instead. - */ - if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP || - !(uid_eq(current_euid(), current_uid()) && - gid_eq(current_egid(), current_gid()))) - set_dumpable(current->mm, suid_dumpable); - else - set_dumpable(current->mm, SUID_DUMP_USER); - perf_event_exec(); __set_task_comm(me, kbasename(bprm->filename), true); @@ -1480,6 +1506,11 @@ static int prepare_bprm_creds(struct linux_binprm *bprm) if (mutex_lock_interruptible(&current->signal->cred_guard_mutex)) return -ERESTARTNOINTR; + if (unlikely(current->signal->exec_bprm)) { + mutex_unlock(&current->signal->cred_guard_mutex); + return -ERESTARTNOINTR; + } + bprm->cred = prepare_exec_creds(); if (likely(bprm->cred)) return 0; diff --git a/fs/proc/base.c b/fs/proc/base.c index ffd54617c354..0da9adfadb48 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2788,6 +2788,12 @@ static ssize_t proc_pid_attr_write(struct file * file, const char __user * buf, if (rv < 0) goto out_free; + if (unlikely(current->signal->exec_bprm)) { + mutex_unlock(&current->signal->cred_guard_mutex); + rv = -ERESTARTNOINTR; + goto out_free; + } + rv = security_setprocattr(PROC_I(inode)->op.lsm, file->f_path.dentry->d_name.name, page, count); diff --git a/include/linux/cred.h b/include/linux/cred.h index f923528d5cc4..b01e309f5686 100644 --- a/include/linux/cred.h +++ b/include/linux/cred.h @@ -159,6 +159,7 @@ extern const struct cred *get_task_cred(struct task_struct *); extern struct cred *cred_alloc_blank(void); extern struct cred *prepare_creds(void); extern struct cred *prepare_exec_creds(void); +extern bool is_dumpability_changed(const struct cred *, const struct cred *); extern int commit_creds(struct cred *); extern void abort_creds(struct cred *); extern const struct cred *override_creds(const struct cred *); diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h index 0014d3adaf84..14df7073a0a8 100644 --- a/include/linux/sched/signal.h +++ b/include/linux/sched/signal.h @@ -234,9 +234,27 @@ struct signal_struct { struct mm_struct *oom_mm; /* recorded mm when the thread group got * killed by the oom killer */ + struct linux_binprm *exec_bprm; /* Used to check ptrace_may_access + * against new credentials while + * de_thread is waiting for other + * traced threads to terminate. + * Set while de_thread is executing. + * The cred_guard_mutex is released + * after de_thread() has called + * zap_other_threads(), therefore + * a fatal signal is guaranteed to be + * already pending in the unlikely + * event, that + * current->signal->exec_bprm happens + * to be non-zero after the + * cred_guard_mutex was acquired. + */ + struct mutex cred_guard_mutex; /* guard against foreign influences on * credential calculations * (notably. ptrace) + * Held while execve runs, except when + * a sibling thread is being traced. * Deprecated do not use in new code. * Use exec_update_lock instead. */ diff --git a/kernel/cred.c b/kernel/cred.c index 98cb4eca23fb..586cb6c7cf6b 100644 --- a/kernel/cred.c +++ b/kernel/cred.c @@ -433,6 +433,28 @@ static bool cred_cap_issubset(const struct cred *set, const struct cred *subset) return false; } +/** + * is_dumpability_changed - Will changing creds from old to new + * affect the dumpability in commit_creds? + * + * Return: false - dumpability will not be changed in commit_creds. + * Return: true - dumpability will be changed to non-dumpable. + * + * @old: The old credentials + * @new: The new credentials + */ +bool is_dumpability_changed(const struct cred *old, const struct cred *new) +{ + if (!uid_eq(old->euid, new->euid) || + !gid_eq(old->egid, new->egid) || + !uid_eq(old->fsuid, new->fsuid) || + !gid_eq(old->fsgid, new->fsgid) || + !cred_cap_issubset(old, new)) + return true; + + return false; +} + /** * commit_creds - Install new credentials upon the current task * @new: The credentials to be assigned @@ -467,11 +489,7 @@ int commit_creds(struct cred *new) get_cred(new); /* we will require a ref for the subj creds too */ /* dumpability changes */ - if (!uid_eq(old->euid, new->euid) || - !gid_eq(old->egid, new->egid) || - !uid_eq(old->fsuid, new->fsuid) || - !gid_eq(old->fsgid, new->fsgid) || - !cred_cap_issubset(old, new)) { + if (is_dumpability_changed(old, new)) { if (task->mm) set_dumpable(task->mm, suid_dumpable); task->pdeath_signal = 0; diff --git a/kernel/ptrace.c b/kernel/ptrace.c index 443057bee87c..eb1c450bb7d7 100644 --- a/kernel/ptrace.c +++ b/kernel/ptrace.c @@ -20,6 +20,7 @@ #include <linux/pagemap.h> #include <linux/ptrace.h> #include <linux/security.h> +#include <linux/binfmts.h> #include <linux/signal.h> #include <linux/uio.h> #include <linux/audit.h> @@ -435,6 +436,28 @@ static int ptrace_attach(struct task_struct *task, long request, if (retval) goto unlock_creds; + if (unlikely(task->in_execve)) { + struct linux_binprm *bprm = task->signal->exec_bprm; + const struct cred __rcu *old_cred; + struct mm_struct *old_mm; + + retval = down_write_killable(&task->signal->exec_update_lock); + if (retval) + goto unlock_creds; + task_lock(task); + old_cred = task->real_cred; + old_mm = task->mm; + rcu_assign_pointer(task->real_cred, bprm->cred); + task->mm = bprm->mm; + retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS); + rcu_assign_pointer(task->real_cred, old_cred); + task->mm = old_mm; + task_unlock(task); + up_write(&task->signal->exec_update_lock); + if (retval) + goto unlock_creds; + } + write_lock_irq(&tasklist_lock); retval = -EPERM; if (unlikely(task->exit_state)) @@ -508,6 +531,14 @@ static int ptrace_traceme(void) { int ret = -EPERM; + if (mutex_lock_interruptible(&current->signal->cred_guard_mutex)) + return -ERESTARTNOINTR; + + if (unlikely(current->signal->exec_bprm)) { + mutex_unlock(&current->signal->cred_guard_mutex); + return -ERESTARTNOINTR; + } + write_lock_irq(&tasklist_lock); /* Are we already being traced? */ if (!current->ptrace) { @@ -523,6 +554,7 @@ static int ptrace_traceme(void) } } write_unlock_irq(&tasklist_lock); + mutex_unlock(&current->signal->cred_guard_mutex); return ret; } diff --git a/kernel/seccomp.c b/kernel/seccomp.c index 255999ba9190..b29bbfa0b044 100644 --- a/kernel/seccomp.c +++ b/kernel/seccomp.c @@ -1955,9 +1955,15 @@ static long seccomp_set_mode_filter(unsigned int flags, * Make sure we cannot change seccomp or nnp state via TSYNC * while another thread is in the middle of calling exec. */ - if (flags & SECCOMP_FILTER_FLAG_TSYNC && - mutex_lock_killable(&current->signal->cred_guard_mutex)) - goto out_put_fd; + if (flags & SECCOMP_FILTER_FLAG_TSYNC) { + if (mutex_lock_killable(&current->signal->cred_guard_mutex)) + goto out_put_fd; + + if (unlikely(current->signal->exec_bprm)) { + mutex_unlock(&current->signal->cred_guard_mutex); + goto out_put_fd; + } + } spin_lock_irq(&current->sighand->siglock); diff --git a/tools/testing/selftests/ptrace/vmaccess.c b/tools/testing/selftests/ptrace/vmaccess.c index 4db327b44586..3b7d81fb99bb 100644 --- a/tools/testing/selftests/ptrace/vmaccess.c +++ b/tools/testing/selftests/ptrace/vmaccess.c @@ -39,8 +39,15 @@ TEST(vmaccess) f = open(mm, O_RDONLY); ASSERT_GE(f, 0); close(f); - f = kill(pid, SIGCONT); - ASSERT_EQ(f, 0); + f = waitpid(-1, NULL, 0); + ASSERT_NE(f, -1); + ASSERT_NE(f, 0); + ASSERT_NE(f, pid); + f = waitpid(-1, NULL, 0); + ASSERT_EQ(f, pid); + f = waitpid(-1, NULL, 0); + ASSERT_EQ(f, -1); + ASSERT_EQ(errno, ECHILD); } TEST(attach) @@ -57,22 +64,24 @@ TEST(attach) sleep(1); k = ptrace(PTRACE_ATTACH, pid, 0L, 0L); - ASSERT_EQ(errno, EAGAIN); - ASSERT_EQ(k, -1); + ASSERT_EQ(k, 0); k = waitpid(-1, &s, WNOHANG); ASSERT_NE(k, -1); ASSERT_NE(k, 0); ASSERT_NE(k, pid); ASSERT_EQ(WIFEXITED(s), 1); ASSERT_EQ(WEXITSTATUS(s), 0); - sleep(1); - k = ptrace(PTRACE_ATTACH, pid, 0L, 0L); + k = waitpid(-1, &s, 0); + ASSERT_EQ(k, pid); + ASSERT_EQ(WIFSTOPPED(s), 1); + ASSERT_EQ(WSTOPSIG(s), SIGTRAP); + k = ptrace(PTRACE_CONT, pid, 0L, 0L); ASSERT_EQ(k, 0); k = waitpid(-1, &s, 0); ASSERT_EQ(k, pid); ASSERT_EQ(WIFSTOPPED(s), 1); ASSERT_EQ(WSTOPSIG(s), SIGSTOP); - k = ptrace(PTRACE_DETACH, pid, 0L, 0L); + k = ptrace(PTRACE_CONT, pid, 0L, 0L); ASSERT_EQ(k, 0); k = waitpid(-1, &s, 0); ASSERT_EQ(k, pid); -- 2.39.2

2 days, 5 hours

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[PATCH 00/12] tools/nolibc: always use 64-bit ino_t, off_t and time-related types

by Thomas Weißschuh

nolibc currently uses 32-bit types for various APIs. These are problematic as their reduced value range can lead to truncated values. Signed-off-by: Thomas Weißschuh <linux(a)weissschuh.net> --- Thomas Weißschuh (12): tools/nolibc: use 64-bit ino_t tools/nolibc: handle 64-bit off_t for llseek tools/nolibc: prefer the llseek syscall tools/nolibc: use 64-bit off_t tools/nolibc: remove now superfluous overflow check in llseek tools/nolibc: remove more __nolibc_enosys() fallbacks tools/nolibc: prefer explicit 64-bit time-related system calls tools/nolibc: gettimeofday(): avoid libgcc 64-bit divisions tools/nolibc: use a custom struct timespec tools/nolibc: always use 64-bit time types selftests/nolibc: test compatibility of timespec and __kernel_timespec tools/nolibc: remove time conversions tools/include/nolibc/arch-s390.h | 3 + tools/include/nolibc/poll.h | 12 ++-- tools/include/nolibc/std.h | 6 +- tools/include/nolibc/sys.h | 21 +++--- tools/include/nolibc/sys/time.h | 2 +- tools/include/nolibc/sys/timerfd.h | 20 +----- tools/include/nolibc/time.h | 96 ++++++---------------------- tools/include/nolibc/types.h | 9 ++- tools/testing/selftests/nolibc/nolibc-test.c | 18 ++++++ 9 files changed, 68 insertions(+), 119 deletions(-) --- base-commit: 90ee85c0e1e4b5804ceebbd731653e10ef3849a6 change-id: 20251001-nolibc-uapi-types-1c072d10fcc7 Best regards, -- Thomas Weißschuh <linux(a)weissschuh.net>

2 days, 11 hours

3
26
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