From 5b81e7556e33e4af42dc1e07eb36f830ca0c4db3 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Fri, 17 May 2013 13:45:31 -0500 Subject: [PATCH 1/1] reparse.c: Read/write from structure --- include/wimlib/reparse.h | 12 ++-- src/reparse.c | 143 ++++++++++++++++++++++++++------------- 2 files changed, 103 insertions(+), 52 deletions(-) diff --git a/include/wimlib/reparse.h b/include/wimlib/reparse.h index 8628d694..dd07949f 100644 --- a/include/wimlib/reparse.h +++ b/include/wimlib/reparse.h @@ -53,17 +53,21 @@ parse_substitute_name(const utf16lechar *substitute_name, u32 rptag); extern int -parse_reparse_data(const u8 *rpbuf, u16 rpbuflen, struct reparse_data *rpdata); +parse_reparse_data(const u8 * restrict rpbuf, u16 rpbuflen, + struct reparse_data * restrict rpdata); extern int -make_reparse_buffer(const struct reparse_data *rpdata, u8 *buf); +make_reparse_buffer(const struct reparse_data * restrict rpdata, + u8 * restrict rpbuf); extern int -wim_inode_get_reparse_data(const struct wim_inode *inode, u8 *rpbuf); +wim_inode_get_reparse_data(const struct wim_inode * restrict inode, + u8 * restrict rpbuf); #ifndef __WIN32__ ssize_t -wim_inode_readlink(const struct wim_inode *inode, char *buf, size_t buf_len); +wim_inode_readlink(const struct wim_inode * restrict inode, char * restrict buf, + size_t buf_len); extern int wim_inode_set_symlink(struct wim_inode *inode, const char *target, diff --git a/src/reparse.c b/src/reparse.c index 766736d4..9ec264d5 100644 --- a/src/reparse.c +++ b/src/reparse.c @@ -26,7 +26,8 @@ #endif #include "wimlib/assert.h" -#include "wimlib/buffer_io.h" +#include "wimlib/compiler.h" +#include "wimlib/endianness.h" #include "wimlib/dentry.h" #include "wimlib/encoding.h" #include "wimlib/error.h" @@ -124,6 +125,25 @@ parse_substitute_name(const utf16lechar *substitute_name, } } +struct reparse_buffer_disk { + le32 rptag; + le16 rpdatalen; + le16 rpreserved; + le16 substitute_name_offset; + le16 substitute_name_nbytes; + le16 print_name_offset; + le16 print_name_nbytes; + union { + struct { + le32 rpflags; + u8 data[REPARSE_POINT_MAX_SIZE - 20]; + } _packed_attribute symlink; + struct { + u8 data[REPARSE_POINT_MAX_SIZE - 16]; + } _packed_attribute junction; + }; +} _packed_attribute; + /* * Read the data from a symbolic link, junction, or mount point reparse point * buffer into a `struct reparse_data'. @@ -132,37 +152,51 @@ parse_substitute_name(const utf16lechar *substitute_name, * description of the format of the reparse point buffers. */ int -parse_reparse_data(const u8 *rpbuf, u16 rpbuflen, struct reparse_data *rpdata) +parse_reparse_data(const u8 * restrict rpbuf, u16 rpbuflen, + struct reparse_data * restrict rpdata) { - const u8 *p = rpbuf; u16 substitute_name_offset; u16 print_name_offset; + const struct reparse_buffer_disk *rpbuf_disk = + (const struct reparse_buffer_disk*)rpbuf; + const u8 *data; memset(rpdata, 0, sizeof(*rpdata)); if (rpbuflen < 16) goto out_invalid; - p = get_u32(p, &rpdata->rptag); + rpdata->rptag = le32_to_cpu(rpbuf_disk->rptag); wimlib_assert(rpdata->rptag == WIM_IO_REPARSE_TAG_SYMLINK || rpdata->rptag == WIM_IO_REPARSE_TAG_MOUNT_POINT); - p = get_u16(p, &rpdata->rpdatalen); - p = get_u16(p, &rpdata->rpreserved); - p = get_u16(p, &substitute_name_offset); - p = get_u16(p, &rpdata->substitute_name_nbytes); - p = get_u16(p, &print_name_offset); - p = get_u16(p, &rpdata->print_name_nbytes); + rpdata->rpdatalen = le16_to_cpu(rpbuf_disk->rpdatalen); + rpdata->rpreserved = le16_to_cpu(rpbuf_disk->rpreserved); + substitute_name_offset = le16_to_cpu(rpbuf_disk->substitute_name_offset); + rpdata->substitute_name_nbytes = le16_to_cpu(rpbuf_disk->substitute_name_nbytes); + print_name_offset = le16_to_cpu(rpbuf_disk->print_name_offset); + rpdata->print_name_nbytes = le16_to_cpu(rpbuf_disk->print_name_nbytes); + + if ((substitute_name_offset & 1) | (print_name_offset & 1) | + (rpdata->substitute_name_nbytes & 1) | (rpdata->print_name_nbytes & 1)) + { + /* Names would be unaligned... */ + goto out_invalid; + } + if (rpdata->rptag == WIM_IO_REPARSE_TAG_SYMLINK) { if (rpbuflen < 20) goto out_invalid; - p = get_u32(p, &rpdata->rpflags); + rpdata->rpflags = le16_to_cpu(rpbuf_disk->symlink.rpflags); + data = rpbuf_disk->symlink.data; + } else { + data = rpbuf_disk->junction.data; } if ((size_t)substitute_name_offset + rpdata->substitute_name_nbytes + - (p - rpbuf) > rpbuflen) + (data - rpbuf) > rpbuflen) goto out_invalid; if ((size_t)print_name_offset + rpdata->print_name_nbytes + - (p - rpbuf) > rpbuflen) + (data - rpbuf) > rpbuflen) goto out_invalid; - rpdata->substitute_name = (utf16lechar*)&p[substitute_name_offset]; - rpdata->print_name = (utf16lechar*)&p[print_name_offset]; + rpdata->substitute_name = (utf16lechar*)&data[substitute_name_offset]; + rpdata->print_name = (utf16lechar*)&data[print_name_offset]; return 0; out_invalid: ERROR("Invalid reparse data"); @@ -178,34 +212,44 @@ out_invalid: * at least REPARSE_POINT_MAX_SIZE bytes long. */ int -make_reparse_buffer(const struct reparse_data *rpdata, u8 *rpbuf) +make_reparse_buffer(const struct reparse_data * restrict rpdata, + u8 * restrict rpbuf) { - u8 *p = rpbuf; - - p = put_u32(p, rpdata->rptag); - p += 2; /* We set ReparseDataLength later */ - p = put_u16(p, rpdata->rpreserved); - p = put_u16(p, 0); /* substitute name offset */ - p = put_u16(p, rpdata->substitute_name_nbytes); /* substitute name nbytes */ - p = put_u16(p, rpdata->substitute_name_nbytes + 2); /* print name offset */ - p = put_u16(p, rpdata->print_name_nbytes); /* print name nbytes */ - if (rpdata->rptag == WIM_IO_REPARSE_TAG_SYMLINK) - p = put_u32(p, rpdata->rpflags); + struct reparse_buffer_disk *rpbuf_disk = + (struct reparse_buffer_disk*)rpbuf; + u8 *data; + + rpbuf_disk->rptag = cpu_to_le32(rpdata->rptag); + rpbuf_disk->rpreserved = cpu_to_le16(rpdata->rpreserved); + rpbuf_disk->substitute_name_offset = cpu_to_le16(0); + rpbuf_disk->substitute_name_nbytes = cpu_to_le16(rpdata->substitute_name_nbytes); + rpbuf_disk->print_name_offset = cpu_to_le16(rpdata->substitute_name_nbytes + 2); + rpbuf_disk->print_name_nbytes = cpu_to_le16(rpdata->print_name_nbytes); + + if (rpdata->rptag == WIM_IO_REPARSE_TAG_SYMLINK) { + rpbuf_disk->symlink.rpflags = cpu_to_le32(rpdata->rpflags); + data = rpbuf_disk->symlink.data; + } else { + data = rpbuf_disk->junction.data; + } + /* We null-terminate the substitute and print names, although this may * not be strictly necessary. Note that the byte counts should not * include the null terminators. */ - if (p + rpdata->substitute_name_nbytes + + if (data + rpdata->substitute_name_nbytes + rpdata->print_name_nbytes + 2 * sizeof(utf16lechar) - rpbuf > REPARSE_POINT_MAX_SIZE) { ERROR("Reparse data is too long!"); return WIMLIB_ERR_INVALID_REPARSE_DATA; } - p = put_bytes(p, rpdata->substitute_name_nbytes, rpdata->substitute_name); - p = put_u16(p, 0); - p = put_bytes(p, rpdata->print_name_nbytes, rpdata->print_name); - p = put_u16(p, 0); - put_u16(rpbuf + 4, p - rpbuf - 8); /* Set ReparseDataLength */ + data = mempcpy(data, rpdata->substitute_name, rpdata->substitute_name_nbytes); + *(utf16lechar*)data = cpu_to_le16(0); + data += 2; + data = mempcpy(data, rpdata->print_name, rpdata->print_name_nbytes); + *(utf16lechar*)data = cpu_to_le16(0); + data += 2; + rpbuf_disk->rpdatalen = cpu_to_le16(data - rpbuf - 8); return 0; } @@ -222,10 +266,12 @@ make_reparse_buffer(const struct reparse_data *rpdata, u8 *rpbuf) * buffer returned by this function. */ int -wim_inode_get_reparse_data(const struct wim_inode *inode, u8 *rpbuf) +wim_inode_get_reparse_data(const struct wim_inode * restrict inode, + u8 * restrict rpbuf) { struct wim_lookup_table_entry *lte; int ret; + struct reparse_buffer_disk *rpbuf_disk; wimlib_assert(inode->i_attributes & FILE_ATTRIBUTE_REPARSE_POINT); @@ -245,16 +291,17 @@ wim_inode_get_reparse_data(const struct wim_inode *inode, u8 *rpbuf) return ret; /* Reconstruct the first 8 bytes of the reparse point buffer */ + rpbuf_disk = (struct reparse_buffer_disk*)rpbuf; /* ReparseTag */ - put_u32(rpbuf, inode->i_reparse_tag); + rpbuf_disk->rptag = cpu_to_le32(inode->i_reparse_tag); /* ReparseDataLength */ - put_u16(rpbuf + 4, wim_resource_size(lte)); + rpbuf_disk->rpdatalen = cpu_to_le16(wim_resource_size(lte)); /* ReparseReserved * XXX this could be one of the unknown fields in the WIM dentry. */ - put_u16(rpbuf + 6, 0); + rpbuf_disk->rpreserved = cpu_to_le16(0); return 0; } @@ -269,10 +316,11 @@ wim_inode_get_reparse_data(const struct wim_inode *inode, u8 *rpbuf) * argument is swapped out with the `struct wim_inode' for a reparse point, and * on failure a negated error code is returned rather than -1 with errno set. */ ssize_t -wim_inode_readlink(const struct wim_inode *inode, char *buf, size_t bufsize) +wim_inode_readlink(const struct wim_inode * restrict inode, + char * restrict buf, size_t bufsize) { int ret; - u8 rpbuf[REPARSE_POINT_MAX_SIZE]; + struct reparse_buffer_disk rpbuf_disk _aligned_attribute(8); u16 rpdatalen; struct reparse_data rpdata; char *link_target; @@ -281,12 +329,11 @@ wim_inode_readlink(const struct wim_inode *inode, char *buf, size_t bufsize) wimlib_assert(inode_is_symlink(inode)); - if (wim_inode_get_reparse_data(inode, rpbuf)) + if (wim_inode_get_reparse_data(inode, (u8*)&rpbuf_disk)) return -EIO; - get_u16(rpbuf + 4, &rpdatalen); - - if (parse_reparse_data(rpbuf, rpdatalen + 8, &rpdata)) + if (parse_reparse_data((const u8*)&rpbuf_disk, + le16_to_cpu(rpbuf_disk.rpdatalen) + 8, &rpdata)) return -EIO; ret = utf16le_to_tstr(rpdata.substitute_name, @@ -336,8 +383,7 @@ wim_inode_set_symlink(struct wim_inode *inode, struct wim_lookup_table *lookup_table) { - u8 rpbuf[REPARSE_POINT_MAX_SIZE]; - u16 rpdatalen; + struct reparse_buffer_disk rpbuf_disk _aligned_attribute(8); struct reparse_data rpdata; static const char abs_subst_name_prefix[12] = "\\\0?\0?\0\\\0C\0:\0"; static const char abs_print_name_prefix[4] = "C\0:\0"; @@ -426,10 +472,11 @@ wim_inode_set_symlink(struct wim_inode *inode, rpdata.rpflags = SYMBOLIC_LINK_RELATIVE; } - ret = make_reparse_buffer(&rpdata, rpbuf); + ret = make_reparse_buffer(&rpdata, (u8*)&rpbuf_disk); if (ret == 0) { - get_u16(rpbuf + 4, &rpdatalen); - ret = inode_set_unnamed_stream(inode, rpbuf + 8, rpdatalen, + ret = inode_set_unnamed_stream(inode, + (u8*)&rpbuf_disk + 8, + le16_to_cpu(rpbuf_disk.rpdatalen), lookup_table); } FREE(name_utf16le); -- 2.43.0