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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: 13950673 X-Patchwork-Delegate: bpf@iogearbox.net Received: from mout.perfora.net (mout.perfora.net [74.208.4.197]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 62DAF4430 for ; Sun, 26 Jan 2025 12:47:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; 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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> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Provags-ID: V03:K1:Bjg3kl/SxsbzXz54Tq5IdMdSap5RqVJxqDCBn1QQsJVhmBA5fWt i3KvIk8h/8wJN6K33pHR+p3RJz8FlsKAYVvZX68rB3vegnqmMhe2zTbq8joxYRK7Iyb5Q2w i2mfbEmT7NMgu6RCfi0sBKmIIvklmsCW3XSp8gMZps2QY7WKJI1kU3j9rlRIEnuaTla+9jb WqGOz/w53TIzcAVVdt7Tg== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:f/te/EooV/M=;0OEjHM0ACfJU79+pV0mUP1QMJHm e98PzfhlPGPLIx8npitoHy60BI82bfP1g+QJNDMzjdBnQCxZ/Vif5/3hicC00XGu9AvCRaV6e VtR64ccsZ0sL2kww0DqQkzX8JUsqJ4Eq5w55SXUl4y22PYSWv1QrzE35RgnL+R/T+1p6py7py vcbcm5clWZVAlrnDfxYfp4Z608VPkB/YnBMezhRYi9n5QnQTPF1YgBTUcn6ooj2QRlV+UhkRy 1uxGIrAhhvxkvNADLAyxtRskziqVY7Hyc1ZLDpBf3S/4FPo0lRz++GxTZ+YjmK9lSH/OL96tz rh0jdeYzuhUaNCEzgD3IudPYJWHeO99iHNaJk/ap5Bb4wLJ83hmPQV7SHeWLIUg6gntTrI0RE H+r3klWiAhNUSPgHjfT3sqe0nZ0nSB2PVbwHAYNVZlWwO8kgPWxSqwz47psVKMJirSn/LjSYg p6UY6WUqPSUQaAs1IRPYuyIlLFXEZacMbrPme8Y73/2ss2Kqt8t0rQxhZylIFVslu4V2oXQv1 nbKjzXiLilbR/HwtynPj4MzS1FQyr2ToB0u4ckHBpnKBGEeIB+4N1XayQfDa4DquiMMEobTM2 EP9UezlZUDkN63qLwwyOyMPF/bI7y/3nd2+zWlCY04swNa3MU7Gs7Ff3oHrLaC6QxxHSblmzW JeDLlJV8vkBH0NHwkfdyZ9cwIFcpyuKOUwdvvPRsnCcZzvBMDhs3SxSW/JDtiIpmKV/VIe0wf CndO6KS/cOmSLlPWLVKU2mqw2ncpRsVvJgH1H2HbD7mX5DlKLNXV7scvAuDx9WYVBJVM0S1Lw jMuCNeROlmbZa711J4Ho2IrY09YxDZskcRXxxSYCtHLlPv+PRi197mrnFgAxbomugWUbgLw2h LCxePMjgb/36Fer2VUu1wedAEWaWdhwUxIF18pVYfcD2RVosQKmgQQ2nTAlqlrInkhCe0W53O nqM9QkjWjlDqVNbHO8ZxV4M3q6vBQMGzl6j4fwNqmqETw2fQEmh8rB1+L4yf8AgADhIc4PbAw RopvBvgQgSuggf5AW9rW+MlSaiuCS6hfkH7oHovlNeFPfj2EcluuBBmJk9HZYMudbQ3+piPY/ JfcO6aqSbEcQXkuQLwPBQUTLgb/UtKJXe6bx7iFAfSKOx2cxQwfg== X-Patchwork-Delegate: bpf@iogearbox.net 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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b=eYsALRRHMxzb+aOIRMWtuDMvLEPtjNqjUeM6I1UtOMet8wNzYtHzRHw4DN6qHnHJ EAbPjNZPgNUXmd6FxMB/TTqyTmg7T9pEtr4nZ+H4hEf/8iWZS1pLnhmkhMgYmzoDT L4VeNS2kxmRdSB5/wFHH+TJvSBJv6kCpmQC0wLV7k1xSb6v9DjzVlHma0DIKDiPE5 9iiEuQan2x/40s8l9h2CNZNJK5Cf5HODYKNcwoBkDhlO1UIozXWB5yjLPxGvIjNIz cstKivbMMm4WRGky5I+qro/gmc75z0n9pv0tmTJNV/nwCwa1CqDMsmeD1fWe5k/RU DibjuDV8BeFN1uWKLQ== X-UI-Sender-Class: 55c96926-9e95-11ee-ae09-1f7a4046a0f6 Received: from localhost ([69.171.251.4]) by mrelay.perfora.net (mreueus002 [74.208.5.2]) with ESMTPSA (Nemesis) id 0MYQD9-1tyM4c3gn3-00KmA8; 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> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Provags-ID: V03:K1:cWTJwAxb+id7fL4BjntpqNqgIcH3atbrD3oI1oa6Wwi1d6Hyx/n lKkZz9WaIW6hdWXuQIfToU6jQ7r9jUY/Z282qG8W77kLRzmrZU8Ipr56QTlWv6R6S3jZVKB 8Wyxk6oqj0v3bzG4hP5EmzYxFuISxQ2Mkow6tRBWS2Fmkma79c1kDVhrykFIDPdfo9kf9Ar Btt802nJ8WQe/RzefKF6A== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:QBEUf+27ax0=;fL+3l6QhyGx68BbSyn32ng9uq8O JJAtTkt0U9JDREHS1RgZpXPaJdbbVDtt97gViF62ApQQIwtzfaGek/MLdHvNf747L/c6nr7tU l90gyidPExT0emwvdMKip/ueP/9pLya2NcpQlQ4KWZJWqNMIPutaxs+HXaLKvsF5yHDGyyaBs +VvzhoGN6ZnxUevJT3bNTQ9ejXklcZyv1S8tI50lxODRxA2+B/reAI7CFTl3Zb27DYTflnWtz hmp6HuOJvg4hA28MjC6qLcRRQgcP/CCOLyNTd0ejy7DICXt39x4SuJkto2Ba1OnuLttg7xKMf NZdCgTE3OKpbmqRLl5MYru4ml735EWU28mXPzSz7LfD0V6t+T/xTb3AOyb1jNPoKeh/og0eT3 WDD6FX/sEjC4d1I3gbrCGdqcx9ViQmdIzi0p3utGYg7bdrxSEF6OG0UqN5S/WX7Uai2v8Mj5o 0G7tQjpHpbfbjs1rJXdO3DGY46VJxGBmm0yGa2zivAU1Zl27luzxxRSwDHQsjA3UaKkuakAzU +E8l2kMOnZUG746mHSfwbyU9ponpl6phdc2aIejg2+2GStrZZdEwmiTLxtliPLWRb/uGLLEcO M9VHnqQgAyc9k+jnHX4PpVy1btRVrqHaXnNPHyVosCyXFLhlhj76aSZKnwNvwwrcDOM5ufPH4 vr0A+4BK3UM8RuCzBsJNy8r0z6iXFyPNSRkC8332yKm8PvewuCyYi89Vma/0BSlQRRZ/27WR1 yfUB8ieNtnqL2ho/Mf3TIN/7AwLP3HIy4g22Dzgg2Yzan6Agn77qbi2pRcPOTKo3zs5Ta8lhS V88Ev4qimoT5Lk4733hBEEBhUzZ+Gz/xmxn6rMQWqh1I8Pk+Lz0GxZqIbRB2MNDljR7zuXp01 Gj8KCQZ3UcLAcqAsmbpr73Sx39zrf143160/tPsKn8XvZkKcwEWM7xMch3pFcaXdAa+vQmnr5 ZQBtycWmnUqw0TG5aMunIuCkx7HQSp+f5LHZzI2Y4D7eDKJEoTF9HfFttIHhChnciNOF8cHAt gsPd7M4DEKLlyrOYbikoOTANTBXh/HJFrK3ZsWhsDOmkNtMfFeAFN20CqT/FpCibREF+t0YTC SnrAx32y66uwFqv8dkyk3iO8aLORi2TBqTmIqeqO29aDANHFjodgxDfk4q0fgBteMxk0G/GVD MUGxmky8xrlamOV2GW2zK+p2zoPq3AijET4ZlTOxF8sxYw4/TEJbZBliUbLw+73w/xMCtoDda OiN0kai8bzDWvroy2sGx0Wo4rA4CNBjzUA== X-Patchwork-Delegate: bpf@iogearbox.net 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; }