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[86.156.84.164]) by smtp.googlemail.com with ESMTPSA id f18-20020a05600c155200b003ede2c59a54sm1416952wmg.37.2023.03.23.03.15.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 23 Mar 2023 03:15:24 -0700 (PDT) From: Lorenzo Stoakes To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, Andrew Morton Cc: Baoquan He , Uladzislau Rezki , Matthew Wilcox , David Hildenbrand , Liu Shixin , Jiri Olsa , Jens Axboe , Alexander Viro , Lorenzo Stoakes Subject: [PATCH v8 2/4] fs/proc/kcore: convert read_kcore() to read_kcore_iter() Date: Thu, 23 Mar 2023 10:15:17 +0000 Message-Id: X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: B09291C0002 X-Rspam-User: X-Stat-Signature: 581r9zc6pob6qyag4a1r94utokh5xmhs X-HE-Tag: 1679566526-722556 X-HE-Meta: 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 eq1itgQL 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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: For the time being we still use a bounce buffer for vread(), however in the next patch we will convert this to interact directly with the iterator and eliminate the bounce buffer altogether. Signed-off-by: Lorenzo Stoakes Reviewed-by: David Hildenbrand --- fs/proc/kcore.c | 36 ++++++++++++++++++------------------ 1 file changed, 18 insertions(+), 18 deletions(-) diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c index 556f310d6aa4..08b795fd80b4 100644 --- a/fs/proc/kcore.c +++ b/fs/proc/kcore.c @@ -24,7 +24,7 @@ #include #include #include -#include +#include #include #include #include @@ -308,9 +308,12 @@ static void append_kcore_note(char *notes, size_t *i, const char *name, } static ssize_t -read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) +read_kcore_iter(struct kiocb *iocb, struct iov_iter *iter) { + struct file *file = iocb->ki_filp; char *buf = file->private_data; + loff_t *fpos = &iocb->ki_pos; + size_t phdrs_offset, notes_offset, data_offset; size_t page_offline_frozen = 1; size_t phdrs_len, notes_len; @@ -318,6 +321,7 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) size_t tsz; int nphdr; unsigned long start; + size_t buflen = iov_iter_count(iter); size_t orig_buflen = buflen; int ret = 0; @@ -356,12 +360,11 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) }; tsz = min_t(size_t, buflen, sizeof(struct elfhdr) - *fpos); - if (copy_to_user(buffer, (char *)&ehdr + *fpos, tsz)) { + if (copy_to_iter((char *)&ehdr + *fpos, tsz, iter) != tsz) { ret = -EFAULT; goto out; } - buffer += tsz; buflen -= tsz; *fpos += tsz; } @@ -398,15 +401,14 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) } tsz = min_t(size_t, buflen, phdrs_offset + phdrs_len - *fpos); - if (copy_to_user(buffer, (char *)phdrs + *fpos - phdrs_offset, - tsz)) { + if (copy_to_iter((char *)phdrs + *fpos - phdrs_offset, tsz, + iter) != tsz) { kfree(phdrs); ret = -EFAULT; goto out; } kfree(phdrs); - buffer += tsz; buflen -= tsz; *fpos += tsz; } @@ -448,14 +450,13 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) min(vmcoreinfo_size, notes_len - i)); tsz = min_t(size_t, buflen, notes_offset + notes_len - *fpos); - if (copy_to_user(buffer, notes + *fpos - notes_offset, tsz)) { + if (copy_to_iter(notes + *fpos - notes_offset, tsz, iter) != tsz) { kfree(notes); ret = -EFAULT; goto out; } kfree(notes); - buffer += tsz; buflen -= tsz; *fpos += tsz; } @@ -497,7 +498,7 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) } if (!m) { - if (clear_user(buffer, tsz)) { + if (iov_iter_zero(tsz, iter) != tsz) { ret = -EFAULT; goto out; } @@ -508,14 +509,14 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) case KCORE_VMALLOC: vread(buf, (char *)start, tsz); /* we have to zero-fill user buffer even if no read */ - if (copy_to_user(buffer, buf, tsz)) { + if (copy_to_iter(buf, tsz, iter) != tsz) { ret = -EFAULT; goto out; } break; case KCORE_USER: /* User page is handled prior to normal kernel page: */ - if (copy_to_user(buffer, (char *)start, tsz)) { + if (copy_to_iter((char *)start, tsz, iter) != tsz) { ret = -EFAULT; goto out; } @@ -531,7 +532,7 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) */ if (!page || PageOffline(page) || is_page_hwpoison(page) || !pfn_is_ram(pfn)) { - if (clear_user(buffer, tsz)) { + if (iov_iter_zero(tsz, iter) != tsz) { ret = -EFAULT; goto out; } @@ -541,17 +542,17 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) case KCORE_VMEMMAP: case KCORE_TEXT: /* - * We use _copy_to_user() to bypass usermode hardening + * We use _copy_to_iter() to bypass usermode hardening * which would otherwise prevent this operation. */ - if (_copy_to_user(buffer, (char *)start, tsz)) { + if (_copy_to_iter((char *)start, tsz, iter) != tsz) { ret = -EFAULT; goto out; } break; default: pr_warn_once("Unhandled KCORE type: %d\n", m->type); - if (clear_user(buffer, tsz)) { + if (iov_iter_zero(tsz, iter) != tsz) { ret = -EFAULT; goto out; } @@ -559,7 +560,6 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) skip: buflen -= tsz; *fpos += tsz; - buffer += tsz; start += tsz; tsz = (buflen > PAGE_SIZE ? PAGE_SIZE : buflen); } @@ -603,7 +603,7 @@ static int release_kcore(struct inode *inode, struct file *file) } static const struct proc_ops kcore_proc_ops = { - .proc_read = read_kcore, + .proc_read_iter = read_kcore_iter, .proc_open = open_kcore, .proc_release = release_kcore, .proc_lseek = default_llseek, -- 2.39.2