From: Jiri Olsa <jolsa@kernel.org> To: stable@vger.kernel.org Cc: linux-mm@kvack.org, bpf@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, "Masami Hiramatsu" <mhiramat@kernel.org>, "Tsahee Zidenberg" <tsahee@annapurnalabs.com>, "Andrii Nakryiko" <andrii@kernel.org>, "Christoph Hellwig" <hch@lst.de>, "Daniel Borkmann" <daniel@iogearbox.net>, "Thomas Gleixner" <tglx@linutronix.de>, "Mahé Tardy" <mahe.tardy@isovalent.com>, linux-arm-kernel@lists.infradead.org Subject: [RFC PATCH stable 5.4 0/8] bpf: Fix bpf_probe_read/bpf_probe_read_str helpers Date: Mon, 22 May 2023 22:33:44 +0200 [thread overview] Message-ID: <20230522203352.738576-1-jolsa@kernel.org> (raw) hi, we see broken access to user space with bpf_probe_read/bpf_probe_read_str helpers on arm64 with 5.4 kernel. The problem is that both helpers try to read user memory by calling probe_kernel_read, which seems to work on x86 but fails on arm64. There are several fixes after v5.4 to address this issue. There was an attempt to fix that in past [1], but it deviated far from upstream changes. This patchset tries to follow the upstream changes with 2 notable exceptions: 1) bpf: Add probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers - this upsgream patch adds new helpers, which we don't need to do, we just need following functions (and related helper's glue): bpf_probe_read_kernel_common bpf_probe_read_kernel_str_common that implement bpf_probe_read* helpers and receive fix in next patch below, ommiting any other hunks 2) bpf: rework the compat kernel probe handling - taking only fixes for functions and realted helper's glue that we took from patch above, ommiting any other hunks It's possible to add new helpers and keep the patches closer to upstream, but I thought trying this way first as RFC without adding any new helpers into stable kernel, which might possibly end up later with additional fixes. Also I'm sending this as RFC, because I might be missing some mm related dependency change, that I'm not aware of. We tested new kernel with our use case on arm64 and x86. thanks, jirka [1] https://yhbt.net/lore/all/YHGMFzQlHomDtZYG@kroah.com/t/ --- Andrii Nakryiko (1): bpf: bpf_probe_read_kernel_str() has to return amount of data read on success Christoph Hellwig (4): maccess: clarify kerneldoc comments maccess: rename strncpy_from_unsafe_user to strncpy_from_user_nofault maccess: rename strncpy_from_unsafe_strict to strncpy_from_kernel_nofault bpf: rework the compat kernel probe handling Daniel Borkmann (3): uaccess: Add strict non-pagefault kernel-space read function bpf: Add probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers bpf: Restrict bpf_probe_read{, str}() only to archs where they work arch/arm/Kconfig | 1 + arch/arm64/Kconfig | 1 + arch/x86/Kconfig | 1 + arch/x86/mm/Makefile | 2 +- arch/x86/mm/maccess.c | 43 ++++++++++++++++++++++++++++++++++++++ include/linux/uaccess.h | 8 +++++-- init/Kconfig | 3 +++ kernel/trace/bpf_trace.c | 140 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------------------------------- kernel/trace/trace_kprobe.c | 2 +- mm/maccess.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++------- 10 files changed, 207 insertions(+), 57 deletions(-) create mode 100644 arch/x86/mm/maccess.c
WARNING: multiple messages have this Message-ID (diff)
From: Jiri Olsa <jolsa@kernel.org> To: stable@vger.kernel.org Cc: linux-mm@kvack.org, bpf@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, "Masami Hiramatsu" <mhiramat@kernel.org>, "Tsahee Zidenberg" <tsahee@annapurnalabs.com>, "Andrii Nakryiko" <andrii@kernel.org>, "Christoph Hellwig" <hch@lst.de>, "Daniel Borkmann" <daniel@iogearbox.net>, "Thomas Gleixner" <tglx@linutronix.de>, "Mahé Tardy" <mahe.tardy@isovalent.com>, linux-arm-kernel@lists.infradead.org Subject: [RFC PATCH stable 5.4 0/8] bpf: Fix bpf_probe_read/bpf_probe_read_str helpers Date: Mon, 22 May 2023 22:33:44 +0200 [thread overview] Message-ID: <20230522203352.738576-1-jolsa@kernel.org> (raw) hi, we see broken access to user space with bpf_probe_read/bpf_probe_read_str helpers on arm64 with 5.4 kernel. The problem is that both helpers try to read user memory by calling probe_kernel_read, which seems to work on x86 but fails on arm64. There are several fixes after v5.4 to address this issue. There was an attempt to fix that in past [1], but it deviated far from upstream changes. This patchset tries to follow the upstream changes with 2 notable exceptions: 1) bpf: Add probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers - this upsgream patch adds new helpers, which we don't need to do, we just need following functions (and related helper's glue): bpf_probe_read_kernel_common bpf_probe_read_kernel_str_common that implement bpf_probe_read* helpers and receive fix in next patch below, ommiting any other hunks 2) bpf: rework the compat kernel probe handling - taking only fixes for functions and realted helper's glue that we took from patch above, ommiting any other hunks It's possible to add new helpers and keep the patches closer to upstream, but I thought trying this way first as RFC without adding any new helpers into stable kernel, which might possibly end up later with additional fixes. Also I'm sending this as RFC, because I might be missing some mm related dependency change, that I'm not aware of. We tested new kernel with our use case on arm64 and x86. thanks, jirka [1] https://yhbt.net/lore/all/YHGMFzQlHomDtZYG@kroah.com/t/ --- Andrii Nakryiko (1): bpf: bpf_probe_read_kernel_str() has to return amount of data read on success Christoph Hellwig (4): maccess: clarify kerneldoc comments maccess: rename strncpy_from_unsafe_user to strncpy_from_user_nofault maccess: rename strncpy_from_unsafe_strict to strncpy_from_kernel_nofault bpf: rework the compat kernel probe handling Daniel Borkmann (3): uaccess: Add strict non-pagefault kernel-space read function bpf: Add probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers bpf: Restrict bpf_probe_read{, str}() only to archs where they work arch/arm/Kconfig | 1 + arch/arm64/Kconfig | 1 + arch/x86/Kconfig | 1 + arch/x86/mm/Makefile | 2 +- arch/x86/mm/maccess.c | 43 ++++++++++++++++++++++++++++++++++++++ include/linux/uaccess.h | 8 +++++-- init/Kconfig | 3 +++ kernel/trace/bpf_trace.c | 140 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------------------------------- kernel/trace/trace_kprobe.c | 2 +- mm/maccess.c | 63 ++++++++++++++++++++++++++++++++++++++++++++++++------- 10 files changed, 207 insertions(+), 57 deletions(-) create mode 100644 arch/x86/mm/maccess.c _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next reply other threads:[~2023-05-22 20:34 UTC|newest] Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-05-22 20:33 Jiri Olsa [this message] 2023-05-22 20:33 ` [RFC PATCH stable 5.4 0/8] bpf: Fix bpf_probe_read/bpf_probe_read_str helpers Jiri Olsa 2023-05-22 20:33 ` [RFC PATCH stable 5.4 1/8] uaccess: Add strict non-pagefault kernel-space read function Jiri Olsa 2023-05-22 20:33 ` Jiri Olsa 2023-05-22 20:33 ` [RFC PATCH stable 5.4 2/8] bpf: Add probe_read_{user, kernel} and probe_read_{user, kernel}_str helpers Jiri Olsa 2023-05-22 20:33 ` Jiri Olsa 2023-05-22 20:33 ` [RFC PATCH stable 5.4 3/8] bpf: Restrict bpf_probe_read{, str}() only to archs where they work Jiri Olsa 2023-05-22 20:33 ` Jiri Olsa 2023-05-22 20:33 ` [RFC PATCH stable 5.4 4/8] maccess: clarify kerneldoc comments Jiri Olsa 2023-05-22 20:33 ` Jiri Olsa 2023-05-22 20:33 ` [RFC PATCH stable 5.4 5/8] maccess: rename strncpy_from_unsafe_user to strncpy_from_user_nofault Jiri Olsa 2023-05-22 20:33 ` Jiri Olsa 2023-05-22 20:33 ` [RFC PATCH stable 5.4 6/8] maccess: rename strncpy_from_unsafe_strict to strncpy_from_kernel_nofault Jiri Olsa 2023-05-22 20:33 ` Jiri Olsa 2023-05-22 20:33 ` [RFC PATCH stable 5.4 7/8] bpf: rework the compat kernel probe handling Jiri Olsa 2023-05-22 20:33 ` Jiri Olsa 2023-05-22 20:33 ` [RFC PATCH stable 5.4 8/8] bpf: bpf_probe_read_kernel_str() has to return amount of data read on success Jiri Olsa 2023-05-22 20:33 ` Jiri Olsa 2023-05-26 18:54 ` [RFC PATCH stable 5.4 0/8] bpf: Fix bpf_probe_read/bpf_probe_read_str helpers Greg KH 2023-05-26 18:54 ` Greg KH 2023-05-28 20:02 ` Jiri Olsa 2023-05-28 20:02 ` Jiri Olsa 2023-05-29 8:37 ` Greg KH 2023-05-29 8:37 ` Greg KH
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