1 files changed, 302 insertions, 0 deletions
diff --git a/squashfs-tools/unsquashfs_xattr.c b/squashfs-tools/unsquashfs_xattr.c
new file mode 100644
index 0000000..377f9e2
--- /dev/null
+++ b/squashfs-tools/unsquashfs_xattr.c
@@ -0,0 +1,302 @@
+/*
+ * Unsquash a squashfs filesystem.  This is a highly compressed read only
+ * filesystem.
+ *
+ * Copyright (c) 2010, 2012, 2019, 2021, 2022
+ * Phillip Lougher <phillip@squashfs.org.uk>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * unsquashfs_xattr.c
+ */
+
+#include "unsquashfs.h"
+#include "xattr.h"
+
+#include <sys/xattr.h>
+
+#ifdef XATTR_NOFOLLOW /* Apple's xattrs */
+	#define lsetxattr(path_, name_, val_, sz_, flags_) \
+		setxattr(path_, name_, val_, sz_, 0, flags_ | XATTR_NOFOLLOW)
+#endif
+
+#define NOSPACE_MAX 10
+
+extern int root_process;
+extern int ignore_errors;
+extern int strict_errors;
+extern regex_t *xattr_exclude_preg;
+extern regex_t *xattr_include_preg;
+
+int has_xattrs(unsigned int xattr)
+{
+	if(xattr == SQUASHFS_INVALID_XATTR ||
+			sBlk.s.xattr_id_table_start == SQUASHFS_INVALID_BLK)
+		return FALSE;
+	else
+		return TRUE;
+}
+
+
+static void print_xattr_name_value(struct xattr_list *xattr, int writer_fd)
+{
+	unsigned char *value = xattr->value;
+	int i, count = 0, printable = TRUE, res;
+
+	for(i = 0; i < xattr->vsize; i++) {
+		if(value[i] < 32 || value[i] > 126) {
+			printable = FALSE;
+			count += 4;
+		} else if(value[i] == '\\')
+			count += 4;
+		else
+			count ++;
+	}
+
+	if(!printable) {
+		unsigned char *new = malloc(count + 2), *dest;
+		if(new == NULL)
+			MEM_ERROR();
+
+		memcpy(new, "0t", 2);
+		count += 2;
+
+		for(dest = new + 2, i = 0; i < xattr->vsize; i++) {
+			if(value[i] < 32 || value[i] > 126 || value[i] == '\\') {
+				sprintf((char *) dest, "\\%03o", value[i]);
+				dest += 4;
+			} else
+				*dest ++ = value[i];
+		}
+
+		value = new;
+	} else
+		count = xattr->vsize;
+	
+	res = dprintf(writer_fd, "%s=", xattr->full_name);
+	if(res == -1)
+		EXIT_UNSQUASH("Failed to write to pseudo output file\n");
+
+	res = write_bytes(writer_fd, (char *) value, count);
+	if(res == -1)
+		EXIT_UNSQUASH("Failed to write to pseudo output file\n");
+
+	res = dprintf(writer_fd, "\n");
+	if(res == -1)
+		EXIT_UNSQUASH("Failed to write to pseudo output file\n");
+
+	if(!printable)
+		free(value);
+}
+
+
+void print_xattr(char *pathname, unsigned int xattr, int writer_fd)
+{
+	unsigned int count;
+	struct xattr_list *xattr_list;
+	int i, failed, res;
+
+	if(!has_xattrs(xattr))
+		return;
+
+	if(xattr >= sBlk.xattr_ids)
+		EXIT_UNSQUASH("File system corrupted - xattr index in inode too large (xattr: %u)\n", xattr);
+
+	xattr_list = get_xattr(xattr, &count, &failed);
+	if(xattr_list == NULL && failed == FALSE)
+		exit(1);
+
+	if(failed)
+		EXIT_UNSQUASH_STRICT("write_xattr: Failed to read one or more xattrs for %s\n", pathname);
+
+	for(i = 0; i < count; i++) {
+		if(xattr_exclude_preg) {
+			int res = regexec(xattr_exclude_preg,
+				xattr_list[i].full_name, (size_t) 0, NULL, 0);
+
+			if(res == 0)
+				continue;
+		}
+
+		if(xattr_include_preg) {
+			int res = regexec(xattr_include_preg,
+				xattr_list[i].full_name, (size_t) 0, NULL, 0);
+
+			if(res)
+				continue;
+		}
+
+		res = dprintf(writer_fd, "%s x ", pathname);
+		if(res == -1)
+			EXIT_UNSQUASH("Failed to write to pseudo output file\n");
+
+		print_xattr_name_value(&xattr_list[i], writer_fd);
+	}
+
+	free_xattr(xattr_list, count);
+}
+
+
+int write_xattr(char *pathname, unsigned int xattr)
+{
+	unsigned int count;
+	struct xattr_list *xattr_list;
+	int i;
+	static int nonsuper_error = FALSE;
+	static int ignore_xattrs = FALSE;
+	static int nospace_error = 0;
+	int failed;
+
+	if(ignore_xattrs || !has_xattrs(xattr))
+		return TRUE;
+
+	if(xattr >= sBlk.xattr_ids)
+		EXIT_UNSQUASH("File system corrupted - xattr index in inode too large (xattr: %u)\n", xattr);
+
+	xattr_list = get_xattr(xattr, &count, &failed);
+	if(xattr_list == NULL && failed == FALSE)
+		exit(1);
+
+	if(failed)
+		EXIT_UNSQUASH_STRICT("write_xattr: Failed to read one or more xattrs for %s\n", pathname);
+
+	for(i = 0; i < count; i++) {
+		int prefix = xattr_list[i].type & SQUASHFS_XATTR_PREFIX_MASK;
+
+		if(ignore_xattrs)
+			continue;
+
+		if(xattr_exclude_preg) {
+			int res = regexec(xattr_exclude_preg,
+				xattr_list[i].full_name, (size_t) 0, NULL, 0);
+
+			if(res == 0)
+				continue;
+		}
+
+		if(xattr_include_preg) {
+			int res = regexec(xattr_include_preg,
+				xattr_list[i].full_name, (size_t) 0, NULL, 0);
+
+			if(res)
+				continue;
+		}
+
+		if(root_process || prefix == SQUASHFS_XATTR_USER) {
+			int res = lsetxattr(pathname, xattr_list[i].full_name,
+				xattr_list[i].value, xattr_list[i].vsize, 0);
+
+			if(res == -1) {
+				if(errno == ENOTSUP) {
+					/*
+					 * If the destination filesystem cannot
+					 * suppport xattrs, print error, and
+					 * disable xattr output as this error is
+					 * unlikely to go away, and printing
+					 * screenfulls of the same error message
+					 * is rather annoying
+					 */
+					ERROR("write_xattr: failed to write "
+						"xattr %s for file %s because " 
+						"extended attributes are not "
+						"supported by the destination "
+						"filesystem\n",
+						xattr_list[i].full_name,
+						pathname);
+					ERROR("Ignoring xattrs in "
+								"filesystem\n");
+					EXIT_UNSQUASH_STRICT("To avoid this error message, "
+						"specify -no-xattrs\n");
+					ignore_xattrs = TRUE;
+				} else if((errno == ENOSPC || errno == EDQUOT)
+						&& nospace_error < NOSPACE_MAX) {
+					/*
+					 * Many filesystems like ext2/3/4 have
+					 * limits on the amount of xattr
+					 * data that can be stored per file
+					 * (typically one block or 4K), so
+					 * we shouldn't disable xattr ouput,
+					 * as the error may be restriced to one
+					 * file only.  If we get a lot of these
+					 * then suppress the error messsage
+					 */
+					EXIT_UNSQUASH_IGNORE("write_xattr: failed to write "
+						"xattr %s for file %s because " 
+						"no extended attribute space "
+						"remaining (per file or "
+						"filesystem limit)\n",
+						xattr_list[i].full_name,
+						pathname);
+					if(++ nospace_error == NOSPACE_MAX)
+						ERROR("%d of these errors "
+							"printed, further error "
+							"messages of this type "
+							"are suppressed!\n",
+							NOSPACE_MAX);
+				} else
+					EXIT_UNSQUASH_IGNORE("write_xattr: failed to write "
+						"xattr %s for file %s because "
+						"%s\n", xattr_list[i].full_name,
+						pathname, strerror(errno));
+				failed = TRUE;
+			}
+		} else if(nonsuper_error == FALSE) {
+			/*
+			 * if extract user xattrs only then
+			 * error message is suppressed, if not
+			 * print error, and then suppress further error
+			 * messages to avoid possible screenfulls of the
+			 * same error message!
+			 */
+			ERROR("write_xattr: could not write xattr %s "
+					"for file %s because you're not "
+					"superuser!\n",
+					xattr_list[i].full_name, pathname);
+			EXIT_UNSQUASH_STRICT("write_xattr: to avoid this error message, either"
+				" specify -xattrs-include '^user.', -no-xattrs, or run as "
+				"superuser!\n");
+			ERROR("Further error messages of this type are "
+				"suppressed!\n");
+			nonsuper_error = TRUE;
+			failed = TRUE;
+		}
+	}
+
+	free_xattr(xattr_list, count);
+
+	return !failed;
+}
+
+
+regex_t *xattr_regex(char *pattern, char *option)
+{
+	int error;
+	regex_t *preg = malloc(sizeof(regex_t));
+
+	if(preg == NULL)
+		MEM_ERROR();
+
+	error = regcomp(preg, pattern, REG_EXTENDED|REG_NOSUB);
+
+	if(error) {
+		char str[1024]; /* overflow safe */
+
+		regerror(error, preg, str, 1024);
+		BAD_ERROR("invalid regex %s in xattrs-%s option, because %s\n",
+				pattern, option, str);
+	}
+
+	return preg;
+}