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b=LKvEeupGPfe5VDHeVwLcPZcsNl9mbdjcbAGupYVSESJqXFas1bc6prQk88qYU4em nWUqkEI/UZE4Z5VcM8pS5YadDBlpdaLASU5quHqwE1xT36cQ7yaxrg/vjxIWTLuIL 3gID7IkRTR/OsWRw8Dm+/aca2X66m5lqGcxzAztn/BhKUOK2GQGmrGISTj2Oc90js cnzGbzz1DVO7UVL85mvZNkKYVbkLMo/VHUHJXEtABEwshSZkt6oD2NQqsDmeiCjb/ t+N8d43rR88zAFeWZuBb3EsSz97IesWLdDkd/mCJ7gtDvnZIjZJq/FjRP6EKb9Y1I oi48YSkuRNjVkHGhmg== X-UI-Sender-Class: 55c96926-9e95-11ee-ae09-1f7a4046a0f6 Received: from localhost ([69.171.251.14]) by mrelay.perfora.net (mreueus003 [74.208.5.2]) with ESMTPSA (Nemesis) id 0LiF41-1t3pED2EV9-00mb9D; Mon, 10 Feb 2025 23:16:38 +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 v7 2/3] bpf: Add bpf_copy_from_user_task_str kfunc Date: Mon, 10 Feb 2025 14:16:25 -0800 Message-ID: <20250210221626.2098522-2-linux@jordanrome.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20250210221626.2098522-1-linux@jordanrome.com> References: <20250210221626.2098522-1-linux@jordanrome.com> MIME-Version: 1.0 X-Provags-ID: V03:K1:iLPVhn1+1T95Aqyp/JoIzbEjvhwnm9MHdVWbq76iWd1Re8CFMgw rw6VicYNKMeojX/XL2VmjLIFPKguyvuuU+J6EyYOAzGPQySiFSjF7ctjENRQvCrZj6Im6kz 2J8ksGTtnLnS40qhd8iKGnWzhTDvXQJMdaFq68jYYtZMNFeG2sJTYO+nWDltRNpYuoEA7BA aYeT/Kun571gsnGj4oHzA== UI-OutboundReport: notjunk:1;M01:P0:chudMfkribQ=;9xayh3pkTZc/XYyilRffcHsje+n Ln2UqEkPNsEeWzt8Dj7X8+1gvMU7c06r/bF4BkGwjOncdvAG501E6pKHkLoE0QWeJ0UtAZEkc Q3HJbCiF9toUTc8I5qN8tzxGPVutmO6lyfFJj43d2X92UjIbOGudc7z+2imbziWVk0HxDlUCv q9BIhZnrfPHaVBMWOtkNRnIgaBqJUrfPUyuW9BRlzEkPnlpdRUp0UPy4GqZtUbkerHyYvKt9h HJFS12daS93TFSCNGLvqTB8ZncJiJh9R+pzYxwaMFgJ3aDkNZVbif9r8RORA/EAtaDJB/EO+w DUgyZqyG5M7WbxVQ6nA7BGmAxY8MZfUjY+0rwCxwSXWiBK8skpTMNjz0Bq1jjHOqB8XCpkpcW lpUvOPkba4inlkrf4wkiGCpAKK27bdrUki5bzhNxqY+7qcyUjsQ6Dc/Cmx+bc5ty9JoRTwHX8 hCMBwfXAwVuem99djaJLmgxj28T+WwJxl/58bRfnFiAtmHNvP65rat0FmIpUyq3r0M1Q7zCTP SPPHiZGzATVvKY786tSI0ukFU6eFCf9YokZ9pZ2sUVhk3fsFwky+Pa858xhso2VRGAeBF6lQ+ 0zyD0v92E7z277r5TBV8w0Zz8IFoKGS5oRXRkOaXj1wMqiAE3kkdzlLeqtoYDbhDOgZ286PSP OTCUW6xewfxS9BnmSvbUVFR94IYf4Bo8C2x8XByfqeOL/pRv8K352sD3PDiGVzMqypEwFg63R VF5EvgPmoarKf7brmaNvXwh3mLPPZcOjAE++AtRMGg6dIDik6ZgIxD6Hi9IQShvtXqCV/oc47 uO23umGm6aYpXHZHu2mPZRE0n2cIbSTPuV5rTTZW++dqnDpAve57JjC86O3LPUC1oq4VQ8It/ SJuRaVbET8RGPMOZSzUc7Shjrxln7ReClmki8llBw+UasB1s0lZrJy/ltOJGkDPMNBBMkZ0OY SVD7J6cc2JV/xaxVEiLRdXsTCcmtjWudA9nRtK9U8+OixIRshd5d6zrRbENf2dOINbu26fGuB SbNY80cl1el9uhYwFCjjqe8ke2Q0bldzI/ViASJ3N8aSsu0GgIl+pXNLqzLvzGOEYoBN7MPQv V/7Zuu1RkGZEjIwLU7lwrraEP52+4r9Twy7FMdw+DLg5Rqiqsd/LlXf8KMxv654UBxeX+QTgz 9ZMkTA8V1RaG9Bb1sJJ9ofr01joUZ7Z14QnPq8mFjwWMqdYOns6VuJxyFd5z8SAqYh3u68C8O 1hPiq0uOqr/aRrFA2DJibSGorAlJ3FvHPpgvbOhhLp+30it+Q9/OL4Z3/aF4MPHHophgN9YB/ eAoU2CS1V/D142OBDZEJFCI02GOHvdKe9RkBSBeKk60bbc= X-Stat-Signature: 6moi1djcwugmbtp6mt1zoqytfb7wpw6z X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 99B17120007 X-Rspam-User: X-HE-Tag: 1739225824-235767 X-HE-Meta: U2FsdGVkX18WAg+WJ18jX6R+PbQ7q8NklcdlpSGZDRAwu2C+Txz+vhXjt3YjLUiCkVP69psooEJcVrqVTIC6AAlb/Jnp1luJZLBJfI8UL9v5yM1dvU/v/St1QuKkncwKzEofnJVPRzgQJrhu+frSMneyCYqYxjnhkFhxoemmOsUrTB/cib8O873gTt+2zNAEnRHRYxTfwqdkKOMsvxOLLMDCEKosdyS1ZCXVXad9ILBB0OVWMVnKDtXty46aHeoFbzrQy8qJ+pzE58wnrBKUcI7r2Y1M4/J8gEFNSSkgP+rdYbagd69lw16lt6aWY9BYVPx6f+C8SvOtV40hK8wpoEisnQMAlIZFirRrcJn5XJfGplAooT6gkmY4dH787Eky9Lo7GuGXwbVeMT8vy8zJbdmNQCKw6bkmR0uJzVltnzW9IInyuX8/5ulbuIr/Plmd3gy11cXK9d6fp+2ZMnZvhZHockZXvaSa2cy2pJVVU5XygHFE6yBmuqXK4EbdK89tZ9pBVETtRaqp7P3YWDFgIKZKLRpYxwMpJ274lWJ/Fbvvg48sJn5BE6x3KuvpbfcThdhNHtixa+NAHC2s4rvl4aU0PpRFWn3DtK3+gtsK2ASF2lz7/bHjFlxa3zQWprDqkMlGP/YjIW8IqdMGFMMwYgE+xm2E8/MP3rq5GTxd59lMhBNRkdzSo1i/LDpIXGA3e6PH+XJLbmW7dFEJ0YXlDADNwtAkRL1eLCahzKe1P6HkMK5ay7EEf2oFuUdq8SLeOi82TU1WHk8ZNPL8YmlV56mImHnnSKPNVxhyNm52F7nEYQ4TLt8jIVtudIpNoVYJxSsuY1yzPKf9M+fMfhfvvERbsgrdtsPF1MY6Bd1mBOJIU1JNsT/t6tRNiown1RsQmdPB1gr4RJvh3Vm1v+jmIxGhdV2AdxC2kQymBAYEC3b/oI+EKkb8WYZ+OyDsPYtTe3AVCpNk+NxJEXSsrPm rQf0rQ0+ 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 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)