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Also chunks reads by page and utilizes `strscpy` for handling null termination. Signed-off-by: Jordan Rome --- include/linux/mm.h | 3 ++ mm/memory.c | 118 +++++++++++++++++++++++++++++++++++++++++++++ mm/nommu.c | 66 +++++++++++++++++++++++++ 3 files changed, 187 insertions(+) -- 2.43.5 diff --git a/include/linux/mm.h b/include/linux/mm.h index f02925447e59..f3a05b3eb2f2 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2485,6 +2485,9 @@ extern int access_process_vm(struct task_struct *tsk, unsigned long addr, extern int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, unsigned int gup_flags); +extern int copy_remote_vm_str(struct task_struct *tsk, unsigned long addr, + void *buf, int len, unsigned int gup_flags); + long get_user_pages_remote(struct mm_struct *mm, unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, diff --git a/mm/memory.c b/mm/memory.c index 398c031be9ba..e1ed5095b258 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -6714,6 +6714,124 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, } EXPORT_SYMBOL_GPL(access_process_vm); +/* + * Copy a string from another process's address space as given in mm. + * If there is any error return -EFAULT. + */ +static int __copy_remote_vm_str(struct mm_struct *mm, unsigned long addr, + void *buf, int len, unsigned int gup_flags) +{ + void *old_buf = buf; + int err = 0; + + if (mmap_read_lock_killable(mm)) + return -EFAULT; + + /* Untag the address before looking up the VMA */ + addr = untagged_addr_remote(mm, addr); + + /* Avoid triggering the temporary warning in __get_user_pages */ + if (!vma_lookup(mm, addr)) { + err = -EFAULT; + goto out; + } + + while (len) { + int bytes, offset, retval; + void *maddr; + struct page *page; + struct vm_area_struct *vma = NULL; + + page = get_user_page_vma_remote(mm, addr, gup_flags, &vma); + + if (IS_ERR(page)) { + /* + * Treat as a total failure for now until we decide how + * to handle the CONFIG_HAVE_IOREMAP_PROT case and + * stack expansion. + */ + err = -EFAULT; + goto out; + } + + bytes = len; + offset = addr & (PAGE_SIZE - 1); + if (bytes > PAGE_SIZE - offset) + bytes = PAGE_SIZE - offset; + + maddr = kmap_local_page(page); + retval = strscpy(buf, maddr + offset, bytes); + unmap_and_put_page(page, maddr); + + if (retval > -1) { + /* Found the end of the string */ + buf += retval; + goto out; + } + + retval = bytes - 1; + buf += retval; + + if (bytes == len) + goto out; + + /* + * Because strscpy always NUL terminates we need to + * copy the last byte in the page if we are going to + * load more pages + */ + addr += retval; + len -= retval; + copy_from_user_page(vma, + page, + addr, + buf, + maddr + (PAGE_SIZE - 1), + 1); + len -= 1; + buf += 1; + addr += 1; + } + +out: + mmap_read_unlock(mm); + if (err) + return err; + + return buf - old_buf; +} + +/** + * copy_remote_vm_str - copy a string from another process's address space. + * @tsk: the task of the target address space + * @addr: start address to read from + * @buf: destination buffer + * @len: number of bytes to copy + * @gup_flags: flags modifying lookup behaviour + * + * The caller must hold a reference on @mm. + * + * Return: number of bytes copied from @addr (source) to @buf (destination); + * not including the trailing NUL. On any error, return -EFAULT. + */ +int copy_remote_vm_str(struct task_struct *tsk, unsigned long addr, + void *buf, int len, unsigned int gup_flags) +{ + struct mm_struct *mm; + int ret; + + mm = get_task_mm(tsk); + if (!mm) + return -EFAULT; + + ret = __copy_remote_vm_str(mm, addr, buf, len, gup_flags); + + mmput(mm); + + return ret; +} +EXPORT_SYMBOL_GPL(copy_remote_vm_str); + /* * Print the name of a VMA. */ diff --git a/mm/nommu.c b/mm/nommu.c index 9cb6e99215e2..480ddf50dec1 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -1701,6 +1701,72 @@ int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, in } EXPORT_SYMBOL_GPL(access_process_vm); +/* + * Copy a string from another process's address space as given in mm. + * If there is any error return -EFAULT. + */ +static int __copy_remote_vm_str(struct mm_struct *mm, unsigned long addr, + void *buf, int len) +{ + int ret; + + if (mmap_read_lock_killable(mm)) + return -EFAULT; + + /* the access must start within one of the target process's mappings */ + vma = find_vma(mm, addr); + if (vma) { + /* don't overrun this mapping */ + if (addr + len >= vma->vm_end) + len = vma->vm_end - addr; + + /* only read mappings where it is permitted */ + if (vma->vm_flags & VM_MAYREAD) { + ret = strscpy(buf, addr, len); + if (ret < 0) + ret = len - 1; + } else { + ret = -EFAULT; + } + } else { + ret = -EFAULT; + } + + mmap_read_unlock(mm); + return ret; +} + +/** + * copy_remote_vm_str - copy a string from another process's address space. + * @tsk: the task of the target address space + * @addr: start address to read from + * @buf: destination buffer + * @len: number of bytes to copy + * @gup_flags: flags modifying lookup behaviour (unused) + * + * The caller must hold a reference on @mm. + * + * Return: number of bytes copied from @addr (source) to @buf (destination); + * not including the trailing NUL. On any error, return -EFAULT. + */ +int copy_remote_vm_str(struct task_struct *tsk, unsigned long addr, + void *buf, int len, unsigned int gup_flags) +{ + struct mm_struct *mm; + int ret; + + mm = get_task_mm(tsk); + if (!mm) + return -EFAULT; + + ret = __copy_remote_vm_str(mm, addr, buf, len); + + mmput(mm); + + return ret; +} +EXPORT_SYMBOL_GPL(copy_remote_vm_str); + /** * nommu_shrink_inode_mappings - Shrink the shared mappings on an inode * @inode: The inode to check From patchwork Sun Jan 26 12:41:46 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jordan Rome X-Patchwork-Id: 13950669 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2ED87C02181 for ; Sun, 26 Jan 2025 12:42:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 40D736B00D2; 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Sun, 26 Jan 2025 13:41:57 +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 v4 2/3] bpf: Add bpf_copy_from_user_task_str kfunc Date: Sun, 26 Jan 2025 04:41:46 -0800 Message-ID: <20250126124147.3154108-2-linux@jordanrome.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20250126124147.3154108-1-linux@jordanrome.com> References: <20250126124147.3154108-1-linux@jordanrome.com> MIME-Version: 1.0 X-Provags-ID: V03:K1:Bjg3kl/SxsbzXz54Tq5IdMdSap5RqVJxqDCBn1QQsJVhmBA5fWt i3KvIk8h/8wJN6K33pHR+p3RJz8FlsKAYVvZX68rB3vegnqmMhe2zTbq8joxYRK7Iyb5Q2w i2mfbEmT7NMgu6RCfi0sBKmIIvklmsCW3XSp8gMZps2QY7WKJI1kU3j9rlRIEnuaTla+9jb WqGOz/w53TIzcAVVdt7Tg== UI-OutboundReport: notjunk:1;M01:P0:d/sj0gjjfgE=;aswIhU3hj3vC18Bfd3tWFjpnAmO BG/h6/Q98SHTzh4tGkg/t5QK8dgNqS/cQ5buVxrVWO7FTjtYcOWAD8Nxtay77T/wpTrY4pizC nK3nvSfGhG+Y6pK213bEH1B/f1xvDEfErntifpyqA/sA1I07ebrY1L1KwnNvMwbmyg0GKmVuQ 8YDHlMKEHA7LLjW/tglgmqtyEEQaICwl6AslmN+b3j9XK/ymCqEOP4tbVWUkMGZdMkC/9S43b EvkyXCeaPaWCVlgCP2s4fjZ8Iol+m76sA4PgwGHfAvuVHIFqGGhCSygChMIgsTSxcJYPVBByv bAedOLbGNBDkqVgF/UFU4Vq1vXrx01IwY/zbCmwsl8kiFcDLKBLDysSSqHoF5ao0dydFvMR7Y HKn5eeK84BEzpU4+YMpOn801Du0tY+upbSZ1c2SUEUOGimyteSc9qvCBcZUAGaMEecmPOgiCn hCpK9wKVX/OaZq4OPFcDxqXpm7TLIah6Ghup3JnQ/UWC4B3lt9HLnmXWFggL/5fHIUKtUI8EZ R3d+s/R8RowyxnpgDQjBeu5usPUhK/0HRDW836UqjfjqLceHOcQw1lvCUFUuthDB42RG7jSWi 8zAbWBUcZ5oxOHjthcfWbtuRd0C02TXq51nn5PhYQop7/n+8CTlnb5hkBdPwLaddvCWE/x+Mq InL4hFHOBFfBl/6+l/LuS/jF49Js4IvgdgbgZuHoxdq5Ez7eTxTPgmQTW5opfRsGQ1n3Eevd3 QP8yzGPBCWEFToxdVNqtnvM4W7vAH+eHlsSo4Sc1HwQ4c8dEIXdKEWDBe8YepH0CnR/ncNARD bVaTTS9lZS4U4iSQF9YJONRWp61tT2UUeNCiLQVbY3WFF1HGN2uIRt5AQ0TiCPToLurHJqCg+ 2BPbmwjF/7xsTQzafzFUtofl5l/XbWQHqqWuw+hmT4Yqt73MJWMxWHIFebHHPn2J5EgNzZti1 pujHwlZe4WbliPEI6F2ARWKn+ALgkX4t9Oijakp4AFIvW5cqlmKzaC3x9uui/QVZZvfZiYEwP y54+qh+l5t7CPSMfsN6XY7IG1Y8MNA+5rMajQPUQVL+rNsBcaT5iUclGK8L8nbxv6ZK+44Yri So0X23wyuBh7cxA8XTc0zkQG5ExV04WKH3OifknM7tZ1lxC9zUnA== X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 85EC6C0008 X-Stat-Signature: boa6tiy9m71gjk1jfjg3jgxzkrp54gsy X-HE-Tag: 1737895319-627698 X-HE-Meta: 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 LTxgvXjV w4xwHVEEggDASyNUJus9zGGzlc5W65e29oPSfIBUmnKYkcCMUkZ3TnRXdwdEptqLgGKNy52ggV1IxkQYuOjfqZV4UH9Awwk0qK1djBHEclq5tAEb5aWiYC9lsTAltR8SUvR583phjTMQ0dZZjn+y6N1Cx+FT1eCugmj8CbBlrLMMHZbHwks1uIjw1C+IbDXDvbDcdAb4PurDtjuLl61UG7KhG3pTGd3/j+KuDpiEffYJIi+g+daWitREXIbrKvpgP2i2yBzxIY/NpZgv1P/giWUrubKVams/jNEh01dKv6648JLQ5yfgywk1gT3dF+57ISIqmzz2ZbanMXpQ1pJ+gWOYiG1kk+0Q9xXXri8XokERqTQmNuRb01Vz0iQrjl032pUah 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. 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) From patchwork Sun Jan 26 12:41:47 2025 Content-Type: text/plain; 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Sun, 26 Jan 2025 13:42:00 +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 v4 3/3] selftests/bpf: Add tests for bpf_copy_from_user_task_str Date: Sun, 26 Jan 2025 04:41:47 -0800 Message-ID: <20250126124147.3154108-3-linux@jordanrome.com> X-Mailer: git-send-email 2.43.5 In-Reply-To: <20250126124147.3154108-1-linux@jordanrome.com> References: <20250126124147.3154108-1-linux@jordanrome.com> MIME-Version: 1.0 X-Provags-ID: V03:K1:cWTJwAxb+id7fL4BjntpqNqgIcH3atbrD3oI1oa6Wwi1d6Hyx/n lKkZz9WaIW6hdWXuQIfToU6jQ7r9jUY/Z282qG8W77kLRzmrZU8Ipr56QTlWv6R6S3jZVKB 8Wyxk6oqj0v3bzG4hP5EmzYxFuISxQ2Mkow6tRBWS2Fmkma79c1kDVhrykFIDPdfo9kf9Ar Btt802nJ8WQe/RzefKF6A== UI-OutboundReport: notjunk:1;M01:P0:W5ZslOkFoBA=;VD+DcmRhs77493Td4mLX6DRtaMH /VDbT/vLSIwJE5etfSwce02ZxWRVnxzibO0Th3Msh5NTWhGVhlpOBTI+oEDj2g8XIHvWxc2OC ltn/QTiGEtw3PnGFb+v3cBib8F6CG4Dh9YRVTkEcHqeHkXBxM+I05dUdnnK+U2Uj1KhNzZqYR Rr0n6Kxap7QJ9bWwS1rNZOk+QLPyX13oqVC5pWa9cwNhVYITOdgPfUXOAdCI2e9OwdVO/YvJ4 A1oIUgjWrnNvLDlhaeAMOYO+eAm8zt3KFkXhP1bn7+0HDaXW3h2+O0WHRErvQCqE/UTzT2ylV AGFjOaNKR8+mDyzcmWA/r68tZftMJDdgrRZ53FqeRpXbo7AJNuaDt1dkTLnYYgA+H1pJ7ue9n nVM6gG3889KeBWT8nLG8V7W0zSXEYEzLsM4skssTIjQBXAa8YDDQ+LnuAwMVCV8AA/YOsbuh7 1Oz9Jsr/X3w1YaEAp+XFk66YxGU9x3/obxMNHRNi3pg/EAYuxjhq631PBiyT00TYVWe7OEte9 hvIm1ox/6Ab0UHNb3QQJWBnFhGv+Q8LhrzTtMfuNLL/UaVPkk11+2eCxO6uhZkaXgJw+9TKeI jYB3MSyBgkqi3vdM8aIx20b09MhJQA3CTtWjzCQhe1r6Rq981G92JQHHQUNaON3wdsXslrzr4 DsNmuxG2hU/V2RK80C3LDwubMO8g6VPrdt8cl4QX2CPkCC3SQMNL4tEBtx4u+QTpN0Kj6vUH3 hKSIVZRXBmb5glb2fNy/bO7FnIwg6KFH10Z75x8Nsv+jVbfr2q9HTE511gTaL7eDGnOL1k/W4 nwYNRMrMxwxZlMCv+mTh31utqlG70+4D038SGRMsRaPEB7H1lSm/w77lB+s3NKiOmmNNAAeAb HEs6LE6n4ylmwzPXmcB7hVNrFzuVKBIz42tJqmgoXxNCQsiHXeW1O0eMDVTmhKD467j7adc8E Vm6d4E9E6UmpKl84ylOyuRvNCS8gEKOTz/0hl5jtYfdEpPPWqzDNIou+WrNWfxBlziQO6h78N sdhMm98jiD1sqa3hq37NGptrgF6WRAVET8JCN4G7V8o/PDLX4+qvIMe+tkaRequdsSyQtd/tr 8WEy6R7ptXNHQWSii1DjRUVZNAIJKCtnjLWOVU+0bBrsM7lOgooQ== X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 8342340008 X-Stat-Signature: qi7kzqoghotbqnobahbo35niyoef4sn5 X-Rspam-User: X-HE-Tag: 1737895327-30141 X-HE-Meta: U2FsdGVkX19HPVQbJVJD1Av2+I20mxfzROSJFNtTxa6Wg0Z3h2Cp6nou0bDem5fHT4YMhVwMJGVBgraWc7+PlsYkR00v9RsqwBSzwxDASHnp8dqdTOaWUPxlMjdtYcbnzSdnzrw5K9nl8iImHu11125EQud0YeTU7l/bKUBfK/mSMC/uDx9saTDKbNzNxyq67gh4m5YoiZCKrkNzBG7RTWtaqho2TH4ek8SF4225XidVV1ShKA0vhYW4XGwUaH0XWf5uKgkyVxPPUwObbn9yhQw851w9uSlkr2p2uo2GZytWzsAJIMPQ1ovNHgOkKxdaQURh2lNcP5QBSE1eZ3c/JqaD0vWvPuTYgTN2L/eBQ1tR6qEWNYEHgeJmax+dRyLEOImd51t9unGaFNu7y/rqntFAGVyyhgcWxjSXHsDLGer64inZHBSZJeMepU8nqVnxvkyyEGPaXqi/xLDWUGXaAATHdEbPd18NrjLuh0ug1r21EeSzysdG29LxbikNpCV+78tuRWKNiRkbE6084hugFGkHJfnc0qKlkvxfFESaZxOUZS9h1pal5SAqFgDz7+3Jd0gGadBYd0y/mP4vx2rLBQlCuDEC423CdS4gJB3nPZkWlMkjgXIUbk+uRgX2YOooKOsnVw0WKYqnk/08kv5cKCwMIHXYV42LFDUrrfH3lsalOtE/d6xgl6qzXQ+ShuDSu+EQ93Cb1WsrZ1KwwykcA2UmA9V+ubzrf9u2fDInpVruAvEkeo7uzYJ45p6sETzXey1m86r3064IR9WUk1qNBZFtUH4vgSPcYQzimLdTRtnRER4IWmEJtJaGsRELiypVGalY7l3jwZBiR4nwWY+zYaGc6r77fLfA8P15YtSoOOiEx2qcVzdS1MsMx35X6YX1qNeN6xs7EsHrwtYG2WL89BvFmgrbyTPLjLz97xPmG/+W0imfffTLDVNCBCPzhFxGiBepmMxFxS++63gXRLC ii7UMpQv CNu644p7JsPE+W+bgCdINNANkDrbRSYdkChf6KCiHB2dLknq2mVMmTN1zkAAgUqn+90O7Ud0juLb5lCznMOJ+5IxkTmGA9ecg8BtiT0EhAioto7dhaaaLnrdgKcR1pFKkbAi4oiijYnCvWIgAuM2bUpMJaw2zM9zgIsxWt0iSNaKpygaNKpWID7sYuXcWPgr/AP5LWfPL3zTzsEG4hsuVrEdJAiMmnOV4KCQdvjP5++vL0l1RPd7xCTGHzQTQ/3QuvrLnsBL+WphXGAYj3/8R9/R/lnJEmqw2Kwxw1Sv1rFpNl1m5r31xgOeuFbifeU34bBE9FaDL7pZnywwG0XQLL5R0unmhvMVncTLMh6DuP9mb5JVrrcdFsqXH/C3SxiRvPPws 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 adds tests for both the happy path and the error path (with and without the BPF_F_PAD_ZEROS flag). Signed-off-by: Jordan Rome --- .../selftests/bpf/prog_tests/bpf_iter.c | 68 +++++++++++ .../selftests/bpf/prog_tests/read_vsyscall.c | 1 + .../selftests/bpf/progs/bpf_iter_tasks.c | 110 ++++++++++++++++++ .../selftests/bpf/progs/read_vsyscall.c | 11 +- 4 files changed, 188 insertions(+), 2 deletions(-) -- 2.43.5 diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c index 6f1bfacd7375..add4a18c33bd 100644 --- a/tools/testing/selftests/bpf/prog_tests/bpf_iter.c +++ b/tools/testing/selftests/bpf/prog_tests/bpf_iter.c @@ -323,19 +323,87 @@ static void test_task_pidfd(void) static void test_task_sleepable(void) { struct bpf_iter_tasks *skel; + int pid, status, err, data_pipe[2], finish_pipe[2], c; + char *test_data = NULL; + char *test_data_long = NULL; + char *data[2]; + + if (!ASSERT_OK(pipe(data_pipe), "data_pipe") || + !ASSERT_OK(pipe(finish_pipe), "finish_pipe")) + return; skel = bpf_iter_tasks__open_and_load(); if (!ASSERT_OK_PTR(skel, "bpf_iter_tasks__open_and_load")) return; + pid = fork(); + if (!ASSERT_GE(pid, 0, "fork")) + return; + + if (pid == 0) { + /* child */ + close(data_pipe[0]); + close(finish_pipe[1]); + + test_data = malloc(sizeof(char) * 10); + strncpy(test_data, "test_data", 10); + test_data[9] = '\0'; + + test_data_long = malloc(sizeof(char) * 5000); + for (int i = 0; i < 5000; ++i) { + if (i % 2 == 0) + test_data_long[i] = 'b'; + else + test_data_long[i] = 'a'; + } + test_data_long[4999] = '\0'; + + data[0] = test_data; + data[1] = test_data_long; + + write(data_pipe[1], &data, sizeof(data)); + + /* keep child alive until after the test */ + err = read(finish_pipe[0], &c, 1); + if (err != 1) + exit(-1); + + close(data_pipe[1]); + close(finish_pipe[0]); + _exit(0); + } + + /* parent */ + close(data_pipe[1]); + close(finish_pipe[0]); + + err = read(data_pipe[0], &data, sizeof(data)); + ASSERT_EQ(err, sizeof(data), "read_check"); + + skel->bss->user_ptr = data[0]; + skel->bss->user_ptr_long = data[1]; + skel->bss->pid = pid; + do_dummy_read(skel->progs.dump_task_sleepable); ASSERT_GT(skel->bss->num_expected_failure_copy_from_user_task, 0, "num_expected_failure_copy_from_user_task"); ASSERT_GT(skel->bss->num_success_copy_from_user_task, 0, "num_success_copy_from_user_task"); + ASSERT_GT(skel->bss->num_expected_failure_copy_from_user_task_str, 0, + "num_expected_failure_copy_from_user_task_str"); + ASSERT_GT(skel->bss->num_success_copy_from_user_task_str, 0, + "num_success_copy_from_user_task_str"); bpf_iter_tasks__destroy(skel); + + write(finish_pipe[1], &c, 1); + err = waitpid(pid, &status, 0); + ASSERT_EQ(err, pid, "waitpid"); + ASSERT_EQ(status, 0, "zero_child_exit"); + + close(data_pipe[0]); + close(finish_pipe[1]); } static void test_task_stack(void) diff --git a/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c b/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c index c7b9ba8b1d06..a8d1eaa67020 100644 --- a/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c +++ b/tools/testing/selftests/bpf/prog_tests/read_vsyscall.c @@ -24,6 +24,7 @@ struct read_ret_desc { { .name = "copy_from_user", .ret = -EFAULT }, { .name = "copy_from_user_task", .ret = -EFAULT }, { .name = "copy_from_user_str", .ret = -EFAULT }, + { .name = "copy_from_user_task_str", .ret = -EFAULT }, }; void test_read_vsyscall(void) diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_tasks.c b/tools/testing/selftests/bpf/progs/bpf_iter_tasks.c index bc10c4e4b4fa..d28d642a64c3 100644 --- a/tools/testing/selftests/bpf/progs/bpf_iter_tasks.c +++ b/tools/testing/selftests/bpf/progs/bpf_iter_tasks.c @@ -9,6 +9,13 @@ char _license[] SEC("license") = "GPL"; uint32_t tid = 0; int num_unknown_tid = 0; int num_known_tid = 0; +void *user_ptr = 0; +void *user_ptr_long = 0; +uint32_t pid = 0; + +static char big_str1[5000]; +static char big_str2[5005]; +static char big_str3[4996]; SEC("iter/task") int dump_task(struct bpf_iter__task *ctx) @@ -35,7 +42,9 @@ int dump_task(struct bpf_iter__task *ctx) } int num_expected_failure_copy_from_user_task = 0; +int num_expected_failure_copy_from_user_task_str = 0; int num_success_copy_from_user_task = 0; +int num_success_copy_from_user_task_str = 0; SEC("iter.s/task") int dump_task_sleepable(struct bpf_iter__task *ctx) @@ -44,6 +53,9 @@ int dump_task_sleepable(struct bpf_iter__task *ctx) struct task_struct *task = ctx->task; static const char info[] = " === END ==="; struct pt_regs *regs; + char task_str1[10] = "aaaaaaaaaa"; + char task_str2[10], task_str3[10]; + char task_str4[20] = "aaaaaaaaaaaaaaaaaaaa"; void *ptr; uint32_t user_data = 0; int ret; @@ -78,8 +90,106 @@ int dump_task_sleepable(struct bpf_iter__task *ctx) BPF_SEQ_PRINTF(seq, "%s\n", info); return 0; } + ++num_success_copy_from_user_task; + /* Read an invalid pointer and ensure we get an error */ + ptr = NULL; + ret = bpf_copy_from_user_task_str((char *)task_str1, sizeof(task_str1), ptr, task, 0); + if (ret >= 0 || task_str1[9] != 'a') { + BPF_SEQ_PRINTF(seq, "%s\n", info); + return 0; + } + + /* Read an invalid pointer and ensure we get error with pad zeros flag */ + ptr = NULL; + ret = bpf_copy_from_user_task_str((char *)task_str1, sizeof(task_str1), + ptr, task, BPF_F_PAD_ZEROS); + if (ret >= 0 || task_str1[9] != '\0') { + BPF_SEQ_PRINTF(seq, "%s\n", info); + return 0; + } + + ++num_expected_failure_copy_from_user_task_str; + + /* Same length as the string */ + ret = bpf_copy_from_user_task_str((char *)task_str2, 10, user_ptr, task, 0); + /* only need to do the task pid check once */ + if (bpf_strncmp(task_str2, 10, "test_data\0") != 0 || ret != 10 || task->tgid != pid) { + BPF_SEQ_PRINTF(seq, "%s\n", info); + return 0; + } + + /* Shorter length than the string */ + ret = bpf_copy_from_user_task_str((char *)task_str3, 2, user_ptr, task, 0); + if (bpf_strncmp(task_str3, 2, "t\0") != 0 || ret != 2) { + BPF_SEQ_PRINTF(seq, "%s\n", info); + return 0; + } + + /* Longer length than the string */ + ret = bpf_copy_from_user_task_str((char *)task_str4, 20, user_ptr, task, 0); + if (bpf_strncmp(task_str4, 10, "test_data\0") != 0 || ret != 10 + || task_str4[sizeof(task_str4) - 1] != 'a') { + BPF_SEQ_PRINTF(seq, "%s\n", info); + return 0; + } + + /* Longer length than the string with pad zeros flag */ + ret = bpf_copy_from_user_task_str((char *)task_str4, 20, user_ptr, task, BPF_F_PAD_ZEROS); + if (bpf_strncmp(task_str4, 10, "test_data\0") != 0 || ret != 10 + || task_str4[sizeof(task_str4) - 1] != '\0') { + BPF_SEQ_PRINTF(seq, "%s\n", info); + return 0; + } + + /* Longer length than the string past a page boundary */ + ret = bpf_copy_from_user_task_str(big_str1, 5000, user_ptr, task, 0); + if (bpf_strncmp(big_str1, 10, "test_data\0") != 0 || ret != 10) { + BPF_SEQ_PRINTF(seq, "%s\n", info); + return 0; + } + + /* String that crosses a page boundary */ + ret = bpf_copy_from_user_task_str(big_str1, 5000, user_ptr_long, task, BPF_F_PAD_ZEROS); + if (bpf_strncmp(big_str1, 4, "baba") != 0 || ret != 5000 + || bpf_strncmp(big_str1 + 4996, 4, "bab\0") != 0) { + BPF_SEQ_PRINTF(seq, "%s\n", info); + return 0; + } + + for (int i = 0; i < 4999; ++i) { + if (i % 2 == 0) { + if (big_str1[i] != 'b') { + BPF_SEQ_PRINTF(seq, "%s\n", info); + return 0; + } + } else { + if (big_str1[i] != 'a') { + BPF_SEQ_PRINTF(seq, "%s\n", info); + return 0; + } + } + } + + /* Longer length than the string that crosses a page boundary */ + ret = bpf_copy_from_user_task_str(big_str2, 5005, user_ptr_long, task, BPF_F_PAD_ZEROS); + if (bpf_strncmp(big_str2, 4, "baba") != 0 || ret != 5000 + || bpf_strncmp(big_str2 + 4996, 5, "bab\0\0") != 0) { + BPF_SEQ_PRINTF(seq, "%s\n", info); + return 0; + } + + /* Shorter length than the string that crosses a page boundary */ + ret = bpf_copy_from_user_task_str(big_str3, 4996, user_ptr_long, task, 0); + if (bpf_strncmp(big_str3, 4, "baba") != 0 || ret != 4996 + || bpf_strncmp(big_str3 + 4992, 4, "bab\0") != 0) { + BPF_SEQ_PRINTF(seq, "%s\n", info); + return 0; + } + + ++num_success_copy_from_user_task_str; + if (ctx->meta->seq_num == 0) BPF_SEQ_PRINTF(seq, " tgid gid data\n"); diff --git a/tools/testing/selftests/bpf/progs/read_vsyscall.c b/tools/testing/selftests/bpf/progs/read_vsyscall.c index 39ebef430059..395591374d4f 100644 --- a/tools/testing/selftests/bpf/progs/read_vsyscall.c +++ b/tools/testing/selftests/bpf/progs/read_vsyscall.c @@ -8,14 +8,16 @@ int target_pid = 0; void *user_ptr = 0; -int read_ret[9]; +int read_ret[10]; char _license[] SEC("license") = "GPL"; /* - * This is the only kfunc, the others are helpers + * These are the kfuncs, the others are helpers */ int bpf_copy_from_user_str(void *dst, u32, const void *, u64) __weak __ksym; +int bpf_copy_from_user_task_str(void *dst, u32, const void *, + struct task_struct *, u64) __weak __ksym; SEC("fentry/" SYS_PREFIX "sys_nanosleep") int do_probe_read(void *ctx) @@ -47,6 +49,11 @@ int do_copy_from_user(void *ctx) read_ret[7] = bpf_copy_from_user_task(buf, sizeof(buf), user_ptr, bpf_get_current_task_btf(), 0); read_ret[8] = bpf_copy_from_user_str((char *)buf, sizeof(buf), user_ptr, 0); + read_ret[9] = bpf_copy_from_user_task_str((char *)buf, + sizeof(buf), + user_ptr, + bpf_get_current_task_btf(), + 0); return 0; }