diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-26 03:03:04 +0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-01-26 03:03:04 +0400 |
commit | 3074c0350b173c9e98b62685e0a61a66d9ff8728 (patch) | |
tree | 28f2cd48f1278983b1fa7d5b4a5895882ce5ca84 | |
parent | f8275f9694b8adf9f3498e747ea4c3e8b984499b (diff) | |
parent | 58ded24f0fcb85bddb665baba75892f6ad0f4b8a (diff) | |
download | linux-3074c0350b173c9e98b62685e0a61a66d9ff8728.tar.xz |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs
Says Tyler:
"Tim's logging message update will be really helpful to users when
they're trying to locate a problematic file in the lower filesystem
with filename encryption enabled.
You'll recognize the fix from Li, as you commented on that.
You should also be familiar with my setattr/truncate improvements,
since you were the one that pointed them out to us (thanks again!).
Andrew noted the /dev/ecryptfs write count sanitization needed to be
improved, so I've got a fix in there for that along with some other
less important cleanups of the /dev/ecryptfs read/write code."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs:
eCryptfs: Fix oops when printing debug info in extent crypto functions
eCryptfs: Remove unused ecryptfs_read()
eCryptfs: Check inode changes in setattr
eCryptfs: Make truncate path killable
eCryptfs: Infinite loop due to overflow in ecryptfs_write()
eCryptfs: Replace miscdev read/write magic numbers
eCryptfs: Report errors in writes to /dev/ecryptfs
eCryptfs: Sanitize write counts of /dev/ecryptfs
ecryptfs: Remove unnecessary variable initialization
ecryptfs: Improve metadata read failure logging
MAINTAINERS: Update eCryptfs maintainer address
-rw-r--r-- | MAINTAINERS | 2 | ||||
-rw-r--r-- | fs/ecryptfs/crypto.c | 54 | ||||
-rw-r--r-- | fs/ecryptfs/ecryptfs_kernel.h | 5 | ||||
-rw-r--r-- | fs/ecryptfs/inode.c | 48 | ||||
-rw-r--r-- | fs/ecryptfs/keystore.c | 5 | ||||
-rw-r--r-- | fs/ecryptfs/miscdev.c | 140 | ||||
-rw-r--r-- | fs/ecryptfs/read_write.c | 96 |
7 files changed, 155 insertions, 195 deletions
diff --git a/MAINTAINERS b/MAINTAINERS index 93c68d5f1cf4..260d9c1785d0 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2402,7 +2402,7 @@ F: net/bridge/netfilter/ebt*.c ECRYPT FILE SYSTEM M: Tyler Hicks <tyhicks@canonical.com> -M: Dustin Kirkland <kirkland@canonical.com> +M: Dustin Kirkland <dustin.kirkland@gazzang.com> L: ecryptfs@vger.kernel.org W: https://launchpad.net/ecryptfs S: Supported diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c index 2a834255c75d..63ab24510649 100644 --- a/fs/ecryptfs/crypto.c +++ b/fs/ecryptfs/crypto.c @@ -417,17 +417,6 @@ static int ecryptfs_encrypt_extent(struct page *enc_extent_page, (unsigned long long)(extent_base + extent_offset), rc); goto out; } - if (unlikely(ecryptfs_verbosity > 0)) { - ecryptfs_printk(KERN_DEBUG, "Encrypting extent " - "with iv:\n"); - ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes); - ecryptfs_printk(KERN_DEBUG, "First 8 bytes before " - "encryption:\n"); - ecryptfs_dump_hex((char *) - (page_address(page) - + (extent_offset * crypt_stat->extent_size)), - 8); - } rc = ecryptfs_encrypt_page_offset(crypt_stat, enc_extent_page, 0, page, (extent_offset * crypt_stat->extent_size), @@ -440,14 +429,6 @@ static int ecryptfs_encrypt_extent(struct page *enc_extent_page, goto out; } rc = 0; - if (unlikely(ecryptfs_verbosity > 0)) { - ecryptfs_printk(KERN_DEBUG, "Encrypt extent [0x%.16llx]; " - "rc = [%d]\n", - (unsigned long long)(extent_base + extent_offset), rc); - ecryptfs_printk(KERN_DEBUG, "First 8 bytes after " - "encryption:\n"); - ecryptfs_dump_hex((char *)(page_address(enc_extent_page)), 8); - } out: return rc; } @@ -543,17 +524,6 @@ static int ecryptfs_decrypt_extent(struct page *page, (unsigned long long)(extent_base + extent_offset), rc); goto out; } - if (unlikely(ecryptfs_verbosity > 0)) { - ecryptfs_printk(KERN_DEBUG, "Decrypting extent " - "with iv:\n"); - ecryptfs_dump_hex(extent_iv, crypt_stat->iv_bytes); - ecryptfs_printk(KERN_DEBUG, "First 8 bytes before " - "decryption:\n"); - ecryptfs_dump_hex((char *) - (page_address(enc_extent_page) - + (extent_offset * crypt_stat->extent_size)), - 8); - } rc = ecryptfs_decrypt_page_offset(crypt_stat, page, (extent_offset * crypt_stat->extent_size), @@ -567,16 +537,6 @@ static int ecryptfs_decrypt_extent(struct page *page, goto out; } rc = 0; - if (unlikely(ecryptfs_verbosity > 0)) { - ecryptfs_printk(KERN_DEBUG, "Decrypt extent [0x%.16llx]; " - "rc = [%d]\n", - (unsigned long long)(extent_base + extent_offset), rc); - ecryptfs_printk(KERN_DEBUG, "First 8 bytes after " - "decryption:\n"); - ecryptfs_dump_hex((char *)(page_address(page) - + (extent_offset - * crypt_stat->extent_size)), 8); - } out: return rc; } @@ -1590,8 +1550,8 @@ int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry, */ int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry) { - int rc = 0; - char *page_virt = NULL; + int rc; + char *page_virt; struct inode *ecryptfs_inode = ecryptfs_dentry->d_inode; struct ecryptfs_crypt_stat *crypt_stat = &ecryptfs_inode_to_private(ecryptfs_inode)->crypt_stat; @@ -1616,11 +1576,13 @@ int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry) ecryptfs_dentry, ECRYPTFS_VALIDATE_HEADER_SIZE); if (rc) { + /* metadata is not in the file header, so try xattrs */ memset(page_virt, 0, PAGE_CACHE_SIZE); rc = ecryptfs_read_xattr_region(page_virt, ecryptfs_inode); if (rc) { printk(KERN_DEBUG "Valid eCryptfs headers not found in " - "file header region or xattr region\n"); + "file header region or xattr region, inode %lu\n", + ecryptfs_inode->i_ino); rc = -EINVAL; goto out; } @@ -1629,7 +1591,8 @@ int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry) ECRYPTFS_DONT_VALIDATE_HEADER_SIZE); if (rc) { printk(KERN_DEBUG "Valid eCryptfs headers not found in " - "file xattr region either\n"); + "file xattr region either, inode %lu\n", + ecryptfs_inode->i_ino); rc = -EINVAL; } if (crypt_stat->mount_crypt_stat->flags @@ -1640,7 +1603,8 @@ int ecryptfs_read_metadata(struct dentry *ecryptfs_dentry) "crypto metadata only in the extended attribute " "region, but eCryptfs was mounted without " "xattr support enabled. eCryptfs will not treat " - "this like an encrypted file.\n"); + "this like an encrypted file, inode %lu\n", + ecryptfs_inode->i_ino); rc = -EINVAL; } } diff --git a/fs/ecryptfs/ecryptfs_kernel.h b/fs/ecryptfs/ecryptfs_kernel.h index a9f29b12fbf2..a2362df58ae8 100644 --- a/fs/ecryptfs/ecryptfs_kernel.h +++ b/fs/ecryptfs/ecryptfs_kernel.h @@ -151,6 +151,11 @@ ecryptfs_get_key_payload_data(struct key *key) * dentry name */ #define ECRYPTFS_TAG_73_PACKET_TYPE 0x49 /* FEK-encrypted filename as * metadata */ +#define ECRYPTFS_MIN_PKT_LEN_SIZE 1 /* Min size to specify packet length */ +#define ECRYPTFS_MAX_PKT_LEN_SIZE 2 /* Pass at least this many bytes to + * ecryptfs_parse_packet_length() and + * ecryptfs_write_packet_length() + */ /* Constraint: ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES >= * ECRYPTFS_MAX_IV_BYTES */ #define ECRYPTFS_FILENAME_MIN_RANDOM_PREPEND_BYTES 16 diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c index 19a8ca4ab1dd..19892d7d2ed1 100644 --- a/fs/ecryptfs/inode.c +++ b/fs/ecryptfs/inode.c @@ -822,18 +822,6 @@ static int truncate_upper(struct dentry *dentry, struct iattr *ia, size_t num_zeros = (PAGE_CACHE_SIZE - (ia->ia_size & ~PAGE_CACHE_MASK)); - - /* - * XXX(truncate) this should really happen at the begginning - * of ->setattr. But the code is too messy to that as part - * of a larger patch. ecryptfs is also totally missing out - * on the inode_change_ok check at the beginning of - * ->setattr while would include this. - */ - rc = inode_newsize_ok(inode, ia->ia_size); - if (rc) - goto out; - if (!(crypt_stat->flags & ECRYPTFS_ENCRYPTED)) { truncate_setsize(inode, ia->ia_size); lower_ia->ia_size = ia->ia_size; @@ -883,6 +871,28 @@ out: return rc; } +static int ecryptfs_inode_newsize_ok(struct inode *inode, loff_t offset) +{ + struct ecryptfs_crypt_stat *crypt_stat; + loff_t lower_oldsize, lower_newsize; + + crypt_stat = &ecryptfs_inode_to_private(inode)->crypt_stat; + lower_oldsize = upper_size_to_lower_size(crypt_stat, + i_size_read(inode)); + lower_newsize = upper_size_to_lower_size(crypt_stat, offset); + if (lower_newsize > lower_oldsize) { + /* + * The eCryptfs inode and the new *lower* size are mixed here + * because we may not have the lower i_mutex held and/or it may + * not be appropriate to call inode_newsize_ok() with inodes + * from other filesystems. + */ + return inode_newsize_ok(inode, lower_newsize); + } + + return 0; +} + /** * ecryptfs_truncate * @dentry: The ecryptfs layer dentry @@ -899,6 +909,10 @@ int ecryptfs_truncate(struct dentry *dentry, loff_t new_length) struct iattr lower_ia = { .ia_valid = 0 }; int rc; + rc = ecryptfs_inode_newsize_ok(dentry->d_inode, new_length); + if (rc) + return rc; + rc = truncate_upper(dentry, &ia, &lower_ia); if (!rc && lower_ia.ia_valid & ATTR_SIZE) { struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); @@ -978,6 +992,16 @@ static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia) } } mutex_unlock(&crypt_stat->cs_mutex); + + rc = inode_change_ok(inode, ia); + if (rc) + goto out; + if (ia->ia_valid & ATTR_SIZE) { + rc = ecryptfs_inode_newsize_ok(inode, ia->ia_size); + if (rc) + goto out; + } + if (S_ISREG(inode->i_mode)) { rc = filemap_write_and_wait(inode->i_mapping); if (rc) diff --git a/fs/ecryptfs/keystore.c b/fs/ecryptfs/keystore.c index ac1ad48c2376..8e3b943e330f 100644 --- a/fs/ecryptfs/keystore.c +++ b/fs/ecryptfs/keystore.c @@ -109,7 +109,7 @@ int ecryptfs_parse_packet_length(unsigned char *data, size_t *size, (*size) += ((unsigned char)(data[1]) + 192); (*length_size) = 2; } else if (data[0] == 255) { - /* Five-byte length; we're not supposed to see this */ + /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ ecryptfs_printk(KERN_ERR, "Five-byte packet length not " "supported\n"); rc = -EINVAL; @@ -126,7 +126,7 @@ out: /** * ecryptfs_write_packet_length * @dest: The byte array target into which to write the length. Must - * have at least 5 bytes allocated. + * have at least ECRYPTFS_MAX_PKT_LEN_SIZE bytes allocated. * @size: The length to write. * @packet_size_length: The number of bytes used to encode the packet * length is written to this address. @@ -146,6 +146,7 @@ int ecryptfs_write_packet_length(char *dest, size_t size, dest[1] = ((size - 192) % 256); (*packet_size_length) = 2; } else { + /* If support is added, adjust ECRYPTFS_MAX_PKT_LEN_SIZE */ rc = -EINVAL; ecryptfs_printk(KERN_WARNING, "Unsupported packet size: [%zd]\n", size); diff --git a/fs/ecryptfs/miscdev.c b/fs/ecryptfs/miscdev.c index 940a82e63dc3..349209dc6a91 100644 --- a/fs/ecryptfs/miscdev.c +++ b/fs/ecryptfs/miscdev.c @@ -218,6 +218,29 @@ out_unlock: return rc; } +/* + * miscdevfs packet format: + * Octet 0: Type + * Octets 1-4: network byte order msg_ctx->counter + * Octets 5-N0: Size of struct ecryptfs_message to follow + * Octets N0-N1: struct ecryptfs_message (including data) + * + * Octets 5-N1 not written if the packet type does not include a message + */ +#define PKT_TYPE_SIZE 1 +#define PKT_CTR_SIZE 4 +#define MIN_NON_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE) +#define MIN_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \ + + ECRYPTFS_MIN_PKT_LEN_SIZE) +/* 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES comes from tag 65 packet format */ +#define MAX_MSG_PKT_SIZE (PKT_TYPE_SIZE + PKT_CTR_SIZE \ + + ECRYPTFS_MAX_PKT_LEN_SIZE \ + + sizeof(struct ecryptfs_message) \ + + 4 + ECRYPTFS_MAX_ENCRYPTED_KEY_BYTES) +#define PKT_TYPE_OFFSET 0 +#define PKT_CTR_OFFSET PKT_TYPE_SIZE +#define PKT_LEN_OFFSET (PKT_TYPE_SIZE + PKT_CTR_SIZE) + /** * ecryptfs_miscdev_read - format and send message from queue * @file: fs/ecryptfs/euid miscdevfs handle (ignored) @@ -237,7 +260,7 @@ ecryptfs_miscdev_read(struct file *file, char __user *buf, size_t count, struct ecryptfs_daemon *daemon; struct ecryptfs_msg_ctx *msg_ctx; size_t packet_length_size; - char packet_length[3]; + char packet_length[ECRYPTFS_MAX_PKT_LEN_SIZE]; size_t i; size_t total_length; uid_t euid = current_euid(); @@ -305,15 +328,8 @@ check_list: packet_length_size = 0; msg_ctx->msg_size = 0; } - /* miscdevfs packet format: - * Octet 0: Type - * Octets 1-4: network byte order msg_ctx->counter - * Octets 5-N0: Size of struct ecryptfs_message to follow - * Octets N0-N1: struct ecryptfs_message (including data) - * - * Octets 5-N1 not written if the packet type does not - * include a message */ - total_length = (1 + 4 + packet_length_size + msg_ctx->msg_size); + total_length = (PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_length_size + + msg_ctx->msg_size); if (count < total_length) { rc = 0; printk(KERN_WARNING "%s: Only given user buffer of " @@ -324,9 +340,10 @@ check_list: rc = -EFAULT; if (put_user(msg_ctx->type, buf)) goto out_unlock_msg_ctx; - if (put_user(cpu_to_be32(msg_ctx->counter), (__be32 __user *)(buf + 1))) + if (put_user(cpu_to_be32(msg_ctx->counter), + (__be32 __user *)(&buf[PKT_CTR_OFFSET]))) goto out_unlock_msg_ctx; - i = 5; + i = PKT_TYPE_SIZE + PKT_CTR_SIZE; if (msg_ctx->msg) { if (copy_to_user(&buf[i], packet_length, packet_length_size)) goto out_unlock_msg_ctx; @@ -391,12 +408,6 @@ out: * @count: Amount of data in @buf * @ppos: Pointer to offset in file (ignored) * - * miscdevfs packet format: - * Octet 0: Type - * Octets 1-4: network byte order msg_ctx->counter (0's for non-response) - * Octets 5-N0: Size of struct ecryptfs_message to follow - * Octets N0-N1: struct ecryptfs_message (including data) - * * Returns the number of bytes read from @buf */ static ssize_t @@ -405,60 +416,78 @@ ecryptfs_miscdev_write(struct file *file, const char __user *buf, { __be32 counter_nbo; u32 seq; - size_t packet_size, packet_size_length, i; - ssize_t sz = 0; + size_t packet_size, packet_size_length; char *data; uid_t euid = current_euid(); - int rc; + unsigned char packet_size_peek[ECRYPTFS_MAX_PKT_LEN_SIZE]; + ssize_t rc; - if (count == 0) - goto out; + if (count == 0) { + return 0; + } else if (count == MIN_NON_MSG_PKT_SIZE) { + /* Likely a harmless MSG_HELO or MSG_QUIT - no packet length */ + goto memdup; + } else if (count < MIN_MSG_PKT_SIZE || count > MAX_MSG_PKT_SIZE) { + printk(KERN_WARNING "%s: Acceptable packet size range is " + "[%d-%lu], but amount of data written is [%zu].", + __func__, MIN_MSG_PKT_SIZE, MAX_MSG_PKT_SIZE, count); + return -EINVAL; + } + + if (copy_from_user(packet_size_peek, &buf[PKT_LEN_OFFSET], + sizeof(packet_size_peek))) { + printk(KERN_WARNING "%s: Error while inspecting packet size\n", + __func__); + return -EFAULT; + } + rc = ecryptfs_parse_packet_length(packet_size_peek, &packet_size, + &packet_size_length); + if (rc) { + printk(KERN_WARNING "%s: Error parsing packet length; " + "rc = [%zd]\n", __func__, rc); + return rc; + } + + if ((PKT_TYPE_SIZE + PKT_CTR_SIZE + packet_size_length + packet_size) + != count) { + printk(KERN_WARNING "%s: Invalid packet size [%zu]\n", __func__, + packet_size); + return -EINVAL; + } + +memdup: data = memdup_user(buf, count); if (IS_ERR(data)) { printk(KERN_ERR "%s: memdup_user returned error [%ld]\n", __func__, PTR_ERR(data)); - goto out; + return PTR_ERR(data); } - sz = count; - i = 0; - switch (data[i++]) { + switch (data[PKT_TYPE_OFFSET]) { case ECRYPTFS_MSG_RESPONSE: - if (count < (1 + 4 + 1 + sizeof(struct ecryptfs_message))) { + if (count < (MIN_MSG_PKT_SIZE + + sizeof(struct ecryptfs_message))) { printk(KERN_WARNING "%s: Minimum acceptable packet " "size is [%zd], but amount of data written is " "only [%zd]. Discarding response packet.\n", __func__, - (1 + 4 + 1 + sizeof(struct ecryptfs_message)), - count); + (MIN_MSG_PKT_SIZE + + sizeof(struct ecryptfs_message)), count); + rc = -EINVAL; goto out_free; } - memcpy(&counter_nbo, &data[i], 4); + memcpy(&counter_nbo, &data[PKT_CTR_OFFSET], PKT_CTR_SIZE); seq = be32_to_cpu(counter_nbo); - i += 4; - rc = ecryptfs_parse_packet_length(&data[i], &packet_size, - &packet_size_length); + rc = ecryptfs_miscdev_response( + &data[PKT_LEN_OFFSET + packet_size_length], + packet_size, euid, current_user_ns(), + task_pid(current), seq); if (rc) { - printk(KERN_WARNING "%s: Error parsing packet length; " - "rc = [%d]\n", __func__, rc); - goto out_free; - } - i += packet_size_length; - if ((1 + 4 + packet_size_length + packet_size) != count) { - printk(KERN_WARNING "%s: (1 + packet_size_length([%zd])" - " + packet_size([%zd]))([%zd]) != " - "count([%zd]). Invalid packet format.\n", - __func__, packet_size_length, packet_size, - (1 + packet_size_length + packet_size), count); - goto out_free; - } - rc = ecryptfs_miscdev_response(&data[i], packet_size, - euid, current_user_ns(), - task_pid(current), seq); - if (rc) printk(KERN_WARNING "%s: Failed to deliver miscdev " - "response to requesting operation; rc = [%d]\n", + "response to requesting operation; rc = [%zd]\n", __func__, rc); + goto out_free; + } break; case ECRYPTFS_MSG_HELO: case ECRYPTFS_MSG_QUIT: @@ -467,12 +496,13 @@ ecryptfs_miscdev_write(struct file *file, const char __user *buf, ecryptfs_printk(KERN_WARNING, "Dropping miscdev " "message of unrecognized type [%d]\n", data[0]); - break; + rc = -EINVAL; + goto out_free; } + rc = count; out_free: kfree(data); -out: - return sz; + return rc; } diff --git a/fs/ecryptfs/read_write.c b/fs/ecryptfs/read_write.c index 3745f7c2b9c2..5c0106f75775 100644 --- a/fs/ecryptfs/read_write.c +++ b/fs/ecryptfs/read_write.c @@ -130,13 +130,18 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset, pgoff_t ecryptfs_page_idx = (pos >> PAGE_CACHE_SHIFT); size_t start_offset_in_page = (pos & ~PAGE_CACHE_MASK); size_t num_bytes = (PAGE_CACHE_SIZE - start_offset_in_page); - size_t total_remaining_bytes = ((offset + size) - pos); + loff_t total_remaining_bytes = ((offset + size) - pos); + + if (fatal_signal_pending(current)) { + rc = -EINTR; + break; + } if (num_bytes > total_remaining_bytes) num_bytes = total_remaining_bytes; if (pos < offset) { /* remaining zeros to write, up to destination offset */ - size_t total_remaining_zeros = (offset - pos); + loff_t total_remaining_zeros = (offset - pos); if (num_bytes > total_remaining_zeros) num_bytes = total_remaining_zeros; @@ -193,15 +198,19 @@ int ecryptfs_write(struct inode *ecryptfs_inode, char *data, loff_t offset, } pos += num_bytes; } - if ((offset + size) > ecryptfs_file_size) { - i_size_write(ecryptfs_inode, (offset + size)); + if (pos > ecryptfs_file_size) { + i_size_write(ecryptfs_inode, pos); if (crypt_stat->flags & ECRYPTFS_ENCRYPTED) { - rc = ecryptfs_write_inode_size_to_metadata( + int rc2; + + rc2 = ecryptfs_write_inode_size_to_metadata( ecryptfs_inode); - if (rc) { + if (rc2) { printk(KERN_ERR "Problem with " "ecryptfs_write_inode_size_to_metadata; " - "rc = [%d]\n", rc); + "rc = [%d]\n", rc2); + if (!rc) + rc = rc2; goto out; } } @@ -273,76 +282,3 @@ int ecryptfs_read_lower_page_segment(struct page *page_for_ecryptfs, flush_dcache_page(page_for_ecryptfs); return rc; } - -#if 0 -/** - * ecryptfs_read - * @data: The virtual address into which to write the data read (and - * possibly decrypted) from the lower file - * @offset: The offset in the decrypted view of the file from which to - * read into @data - * @size: The number of bytes to read into @data - * @ecryptfs_file: The eCryptfs file from which to read - * - * Read an arbitrary amount of data from an arbitrary location in the - * eCryptfs page cache. This is done on an extent-by-extent basis; - * individual extents are decrypted and read from the lower page - * cache (via VFS reads). This function takes care of all the - * address translation to locations in the lower filesystem. - * - * Returns zero on success; non-zero otherwise - */ -int ecryptfs_read(char *data, loff_t offset, size_t size, - struct file *ecryptfs_file) -{ - struct inode *ecryptfs_inode = ecryptfs_file->f_dentry->d_inode; - struct page *ecryptfs_page; - char *ecryptfs_page_virt; - loff_t ecryptfs_file_size = i_size_read(ecryptfs_inode); - loff_t data_offset = 0; - loff_t pos; - int rc = 0; - - if ((offset + size) > ecryptfs_file_size) { - rc = -EINVAL; - printk(KERN_ERR "%s: Attempt to read data past the end of the " - "file; offset = [%lld]; size = [%td]; " - "ecryptfs_file_size = [%lld]\n", - __func__, offset, size, ecryptfs_file_size); - goto out; - } - pos = offset; - while (pos < (offset + size)) { - pgoff_t ecryptfs_page_idx = (pos >> PAGE_CACHE_SHIFT); - size_t start_offset_in_page = (pos & ~PAGE_CACHE_MASK); - size_t num_bytes = (PAGE_CACHE_SIZE - start_offset_in_page); - size_t total_remaining_bytes = ((offset + size) - pos); - - if (num_bytes > total_remaining_bytes) - num_bytes = total_remaining_bytes; - ecryptfs_page = ecryptfs_get_locked_page(ecryptfs_inode, - ecryptfs_page_idx); - if (IS_ERR(ecryptfs_page)) { - rc = PTR_ERR(ecryptfs_page); - printk(KERN_ERR "%s: Error getting page at " - "index [%ld] from eCryptfs inode " - "mapping; rc = [%d]\n", __func__, - ecryptfs_page_idx, rc); - goto out; - } - ecryptfs_page_virt = kmap_atomic(ecryptfs_page, KM_USER0); - memcpy((data + data_offset), - ((char *)ecryptfs_page_virt + start_offset_in_page), - num_bytes); - kunmap_atomic(ecryptfs_page_virt, KM_USER0); - flush_dcache_page(ecryptfs_page); - SetPageUptodate(ecryptfs_page); - unlock_page(ecryptfs_page); - page_cache_release(ecryptfs_page); - pos += num_bytes; - data_offset += num_bytes; - } -out: - return rc; -} -#endif /* 0 */ |