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b=CwR/Zc7zCuTY4OsXyO6Qmd74qGjuvjIS1OE0pRFormT09eJ4CxF+EiqJjfRs8OG/ nKA8n9gaIpXpndrne0Wk/vN3FGF3SK3SdjlTIbJq9umQYo8EwIKTEsRqVJlcYLZtL MfYeiXJhNt7vGvz0HVneNUowxpvkY/GwI98IlhGcOCSAKEBXb/JGx16NSoCaggyOk 6oHck8x4w5A8Yb0FCt98qyqLfQG+E1inzXFsYj4COHsi/tZlo23eAVqjyoAwLslhB QJDZ2MSQSlohfaanP/C+LpuWUg2H5354T5cUDc+9iXkoGfDNV4+7S29tuueqYcBTO ccT15K6cD7soGrHstA== X-UI-Sender-Class: 55c96926-9e95-11ee-ae09-1f7a4046a0f6 Received: from localhost ([69.171.251.115]) by mrelay.perfora.net (mreueus003 [74.208.5.2]) with ESMTPSA (Nemesis) id 0MH1qm-1tdhEB1qtO-00DXUA; Thu, 13 Feb 2025 16:21:37 +0100 From: Jordan Rome To: bpf@vger.kernel.org Cc: linux-mm@kvack.org, Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Kernel Team , Andrew Morton , Shakeel Butt , Alexander Potapenko Subject: [bpf-next v8 2/3] bpf: Add bpf_copy_from_user_task_str kfunc Date: Thu, 13 Feb 2025 07:21:24 -0800 Message-ID: <20250213152125.1837400-2-linux@jordanrome.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20250213152125.1837400-1-linux@jordanrome.com> References: <20250213152125.1837400-1-linux@jordanrome.com> MIME-Version: 1.0 X-Provags-ID: V03:K1:M2HqTh52VzVoW28hZaqWA8+HYrSAYL9Nms0h4Rw5isAfIEJewQ1 twyuDCDsOcjnxNjxwbS9qKv/fJhN7ZDKDK2BJjFIyaIk2tgWwJdDxaIpFxUVZa3FH9CcQjh DQQ3eS6f6v9yds5bNQ2yO2mUtp/zc9gpi8KpG/TOcd5EaXnvIUwcr4aXwi4SQYtZD45Kwpt /QVaH9FcwHfNLezznwm9g== UI-OutboundReport: notjunk:1;M01:P0:XFeo8jdd6/k=;jZRp5DXm0QPSSXAQxaDXmup3ZT0 zR+/WroUAQFWUZCBDkVgG/V2UASfi8OoDYhzGkS89SVYOWfD0xltc0B5XkK9TXS/lRDRy6Azi d6/6O0yjD9XkWd/ZDJhVK0UuyM8MVolFgm/opRcqVBbCafACwiriTEvobZAYvxGMAgu2tvVHb iGOHV5cDB+1EINtc/Numz+kf4qFr9tSgL2ieceUJ2NeLZEFoDsV6panrVEsjcfXMI+maPd8Nk ohg4ygLEDE7MWuVpgQCrwxwXiCPc8TYJGzvjaDv0wVyb3bOTDFkZrxyTBL6Z1evwjUAcqB/EJ U0LvKowLd7lJ8YcOADqYf9lTmEszlnV6pBGboNZ0A55ElQpxjA5mPOu+vTZNVopspo3YLmRMa Wz8RlzOjlDXyTlRxglb3hNJaEHBPOAM+Q2j+ZQrGOZmEifmq5GnwAJ+6KYtrLeWPuhQJKI/ve fGgSVS50GyrpsTgQrZ5r9CzkUtDCK/J2pctHqRwdInw8Q5X0Tf5MVVgFV/2iCpzBxWms0UgNv yG+ybmgcV3pFRyRR4rbROm/VS5MQk78eqHzyDWlaB0H1+XxaLEAVCjht9ZK9mzGhwGEaV+JBr mlXO76Lroz3roGJf2TucOPu/ofHoCAldH4Yz7q8wRE7eN79t15h12Ox9AgqJ41MtYDZEIjIvD Bg1Xe/Mcqh8hDsYId7c9+sXTQ3kSRpLryCZ++8kdj1d4lldbTjZvpfU1apX6qhq0m3ycCdgZc NVNJj7qDXm0RwwAL0Wf/hZarWP8IyzAxrl0JMFoykAcnwjZhAiGEjv7FVcIph4KmmPnC//5AC k2IqMvXnTpREpcPu+rhu78eW1UAkv/fs3FmDuHDKJzYmbsvUcr26gPS+y01jf7F1GX37v7tPn 41RgAHATAPKRQTXDAQmNGCL2dj0VGovS3l7q+ibKBFFRdQP5xy9vGbT9/jrw56um6XwyhBv9Z NnHjFml9xzg4HSaEOk9r5EftwPCSUHFTS8hH0gJvuUdBQxa+vIDBOjIZtvl+hMNQgfEXX50UX AHm+YY8LMZMf3p7cMQW4o8YS6UvxphNXNWLWDKT26+AcP27V64Kc87tJFjFFya9QacsQmwhmJ zAWE6sAHdtZ1+UCxigmvTsQgqmGee5Fmdn6C4dacWuDvheioCAmfp7urnGJVPtAaZTVMFCv/4 fFKIq1RgGJZ7rLPUOJvXXqDpZ8ow0tt31xXuun+pYQcQBUv4aYJbF98uB+AaqBIVMFrIj5c1L HpNlzRy5ifc3FXnKRUarCsHsxMJnK/JQE7aYrl5j+oYjVHweOXbq4ZSUG4zd7M3/iR8Iknupx ylp1H4qd45vpxQqEvYXZnXGCUQSbdmY69DUwoul7ff13FjLV3Pcw+HFXC06mvh7wTMa X-Stat-Signature: w3wbcioaju9xe8mbcktxhy7mr3kkzj6u X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 95F9B4000F X-Rspam-User: X-HE-Tag: 1739460120-711340 X-HE-Meta: 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 U+HR4r5l ZwWh6mFTaHrFxhk6F8zTMw+O/Za34/n9v1IqS8C0d6CScrISSgVblYcELaC3QGsUg0IFFJ5CSs4YhWiiohj7WYKM8XMud+ntsl/e4o7l+vKxbwMRiGxwCnzYOheifS7RX8FCh9YnIfLhjQE7heHbg3lslpczx/HQL/JugixQLsgnXbuta8wbkpxBx17LF7aGOsxdnFYcfCnbIpJuUw1nm/254QVta0donqEXa3tszpX+ii2qNtK4QmyuOaWCWNYxu0NyXkQiDQBBQmpBqAzF0mGZaWf+JyuvMtM0QIY/hYAj6BhBh1xJY5MO/2/5ecdPG446OW+bJep3fLsOSgTB/Ze1yEk/ndwaV6tBEkHjdIayHKvweylbbuTXLyMKFSSIEbSG9Fv2TYinmdkaKbI2VlITelQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: This new kfunc will be able to copy a string from another process's/task's address space. This is similar to `bpf_copy_from_user_str` but accepts a `struct task_struct*` argument. Acked-by: Andrii Nakryiko Signed-off-by: Jordan Rome --- kernel/bpf/helpers.c | 48 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 48 insertions(+) -- 2.43.5 diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index f27ce162427a..a33f72a4c31f 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -3082,6 +3082,53 @@ __bpf_kfunc void bpf_local_irq_restore(unsigned long *flags__irq_flag) local_irq_restore(*flags__irq_flag); } +/** + * bpf_copy_from_user_task_str() - Copy a string from an task's address space + * @dst: Destination address, in kernel space. This buffer must be + * at least @dst__sz bytes long. + * @dst__sz: Maximum number of bytes to copy, includes the trailing NUL. + * @unsafe_ptr__ign: Source address in the task's address space. + * @tsk: The task whose address space will be used + * @flags: The only supported flag is BPF_F_PAD_ZEROS + * + * Copies a NUL terminated string from a task's address space to @dst__sz + * buffer. If user string is too long this will still ensure zero termination + * in the @dst__sz buffer unless buffer size is 0. + * + * If BPF_F_PAD_ZEROS flag is set, memset the tail of @dst__sz to 0 on success + * and memset all of @dst__sz on failure. + * + * Return: The number of copied bytes on success including the NUL terminator. + * A negative error code on failure. + */ +__bpf_kfunc int bpf_copy_from_user_task_str(void *dst, + u32 dst__sz, + const void __user *unsafe_ptr__ign, + struct task_struct *tsk, + u64 flags) +{ + int ret; + + if (unlikely(flags & ~BPF_F_PAD_ZEROS)) + return -EINVAL; + + if (unlikely(!dst__sz)) + return 0; + + ret = copy_remote_vm_str(tsk, (unsigned long)unsafe_ptr__ign, dst, dst__sz, 0); + + if (ret < 0) { + if (flags & BPF_F_PAD_ZEROS) + memset(dst, 0, dst__sz); + return ret; + } + + if (flags & BPF_F_PAD_ZEROS) + memset(dst + ret, 0, dst__sz - ret); + + return ret + 1; +} + __bpf_kfunc_end_defs(); BTF_KFUNCS_START(generic_btf_ids) @@ -3174,6 +3221,7 @@ BTF_ID_FLAGS(func, bpf_iter_bits_new, KF_ITER_NEW) BTF_ID_FLAGS(func, bpf_iter_bits_next, KF_ITER_NEXT | KF_RET_NULL) BTF_ID_FLAGS(func, bpf_iter_bits_destroy, KF_ITER_DESTROY) BTF_ID_FLAGS(func, bpf_copy_from_user_str, KF_SLEEPABLE) +BTF_ID_FLAGS(func, bpf_copy_from_user_task_str, KF_SLEEPABLE) BTF_ID_FLAGS(func, bpf_get_kmem_cache) BTF_ID_FLAGS(func, bpf_iter_kmem_cache_new, KF_ITER_NEW | KF_SLEEPABLE) BTF_ID_FLAGS(func, bpf_iter_kmem_cache_next, KF_ITER_NEXT | KF_RET_NULL | KF_SLEEPABLE)