e2fsprogs: Fix CVE-2019-5094 in libsupport

This adds the following patch from debian:
https://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git/commit/?h=debian/stable&id=09fe1fd2a1f9efc3091b4fc61f1876d0785956a8
libsupport: add checks to prevent buffer overrun bugs in quota code

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
(cherry picked from commit 0062aad8ecc9bbe36c55895fd78fcaf9a406b006)

package/utils/e2fsprogs/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=e2fsprogs
 PKG_VERSION:=1.44.5
-PKG_RELEASE:=1
+PKG_RELEASE:=2
 
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.xz
 PKG_SOURCE_URL:=@KERNEL/linux/kernel/people/tytso/e2fsprogs/v$(PKG_VERSION)/

package/utils/e2fsprogs/patches/100-CVE-2019-5094-libsupport.patch

@@ -0,0 +1,203 @@
+From 09fe1fd2a1f9efc3091b4fc61f1876d0785956a8 Mon Sep 17 00:00:00 2001
+From: Theodore Ts'o <tytso@mit.edu>
+Date: Sun, 1 Sep 2019 00:59:16 -0400
+Subject: libsupport: add checks to prevent buffer overrun bugs in quota code
+
+A maliciously corrupted file systems can trigger buffer overruns in
+the quota code used by e2fsck.  To fix this, add sanity checks to the
+quota header fields as well as to block number references in the quota
+tree.
+
+Addresses: CVE-2019-5094
+Addresses: TALOS-2019-0887
+Signed-off-by: Theodore Ts'o <tytso@mit.edu>
+(cherry picked from commit 8dbe7b475ec5e91ed767239f0e85880f416fc384)
+---
+ lib/support/mkquota.c      |  1 +
+ lib/support/quotaio_tree.c | 71 ++++++++++++++++++++++++++++++----------------
+ lib/support/quotaio_v2.c   | 28 ++++++++++++++++++
+ 3 files changed, 76 insertions(+), 24 deletions(-)
+
+--- a/lib/support/mkquota.c
++++ b/lib/support/mkquota.c
+@@ -671,6 +671,7 @@ errcode_t quota_compare_and_update(quota
+ 	err = qh.qh_ops->scan_dquots(&qh, scan_dquots_callback, &scan_data);
+ 	if (err) {
+ 		log_debug("Error scanning dquots");
++		*usage_inconsistent = 1;
+ 		goto out_close_qh;
+ 	}
+ 
+--- a/lib/support/quotaio_tree.c
++++ b/lib/support/quotaio_tree.c
+@@ -540,6 +540,17 @@ struct dquot *qtree_read_dquot(struct qu
+ 	return dquot;
+ }
+ 
++static int check_reference(struct quota_handle *h, unsigned int blk)
++{
++	if (blk >= h->qh_info.u.v2_mdqi.dqi_qtree.dqi_blocks) {
++		log_err("Illegal reference (%u >= %u) in %s quota file",
++			blk, h->qh_info.u.v2_mdqi.dqi_qtree.dqi_blocks,
++			quota_type2name(h->qh_type));
++		return -1;
++	}
++	return 0;
++}
++
+ /*
+  * Scan all dquots in file and call callback on each
+  */
+@@ -558,7 +569,7 @@ static int report_block(struct dquot *dq
+ 	int entries, i;
+ 
+ 	if (!buf)
+-		return 0;
++		return -1;
+ 
+ 	set_bit(bitmap, blk);
+ 	read_blk(dquot->dq_h, blk, buf);
+@@ -580,23 +591,12 @@ static int report_block(struct dquot *dq
+ 	return entries;
+ }
+ 
+-static void check_reference(struct quota_handle *h, unsigned int blk)
+-{
+-	if (blk >= h->qh_info.u.v2_mdqi.dqi_qtree.dqi_blocks)
+-		log_err("Illegal reference (%u >= %u) in %s quota file. "
+-			"Quota file is probably corrupted.\n"
+-			"Please run e2fsck (8) to fix it.",
+-			blk,
+-			h->qh_info.u.v2_mdqi.dqi_qtree.dqi_blocks,
+-			quota_type2name(h->qh_type));
+-}
+-
+ static int report_tree(struct dquot *dquot, unsigned int blk, int depth,
+ 		       char *bitmap,
+ 		       int (*process_dquot) (struct dquot *, void *),
+ 		       void *data)
+ {
+-	int entries = 0, i;
++	int entries = 0, ret, i;
+ 	dqbuf_t buf = getdqbuf();
+ 	__le32 *ref = (__le32 *) buf;
+ 
+@@ -607,22 +607,40 @@ static int report_tree(struct dquot *dqu
+ 	if (depth == QT_TREEDEPTH - 1) {
+ 		for (i = 0; i < QT_BLKSIZE >> 2; i++) {
+ 			blk = ext2fs_le32_to_cpu(ref[i]);
+-			check_reference(dquot->dq_h, blk);
+-			if (blk && !get_bit(bitmap, blk))
+-				entries += report_block(dquot, blk, bitmap,
+-							process_dquot, data);
++			if (check_reference(dquot->dq_h, blk)) {
++				entries = -1;
++				goto errout;
++			}
++			if (blk && !get_bit(bitmap, blk)) {
++				ret = report_block(dquot, blk, bitmap,
++						   process_dquot, data);
++				if (ret < 0) {
++					entries = ret;
++					goto errout;
++				}
++				entries += ret;
++			}
+ 		}
+ 	} else {
+ 		for (i = 0; i < QT_BLKSIZE >> 2; i++) {
+ 			blk = ext2fs_le32_to_cpu(ref[i]);
+ 			if (blk) {
+-				check_reference(dquot->dq_h, blk);
+-				entries += report_tree(dquot, blk, depth + 1,
+-						       bitmap, process_dquot,
+-						       data);
++				if (check_reference(dquot->dq_h, blk)) {
++					entries = -1;
++					goto errout;
++				}
++				ret = report_tree(dquot, blk, depth + 1,
++						  bitmap, process_dquot,
++						  data);
++				if (ret < 0) {
++					entries = ret;
++					goto errout;
++				}
++				entries += ret;
+ 			}
+ 		}
+ 	}
++errout:
+ 	freedqbuf(buf);
+ 	return entries;
+ }
+@@ -642,6 +660,7 @@ int qtree_scan_dquots(struct quota_handl
+ 		      int (*process_dquot) (struct dquot *, void *),
+ 		      void *data)
+ {
++	int ret;
+ 	char *bitmap;
+ 	struct v2_mem_dqinfo *v2info = &h->qh_info.u.v2_mdqi;
+ 	struct qtree_mem_dqinfo *info = &v2info->dqi_qtree;
+@@ -655,10 +674,14 @@ int qtree_scan_dquots(struct quota_handl
+ 		ext2fs_free_mem(&dquot);
+ 		return -1;
+ 	}
+-	v2info->dqi_used_entries = report_tree(dquot, QT_TREEOFF, 0, bitmap,
+-					       process_dquot, data);
++	ret = report_tree(dquot, QT_TREEOFF, 0, bitmap, process_dquot, data);
++	if (ret < 0)
++		goto errout;
++	v2info->dqi_used_entries = ret;
+ 	v2info->dqi_data_blocks = find_set_bits(bitmap, info->dqi_blocks);
++	ret = 0;
++errout:
+ 	ext2fs_free_mem(&bitmap);
+ 	ext2fs_free_mem(&dquot);
+-	return 0;
++	return ret;
+ }
+--- a/lib/support/quotaio_v2.c
++++ b/lib/support/quotaio_v2.c
+@@ -175,6 +175,8 @@ static int v2_check_file(struct quota_ha
+ static int v2_init_io(struct quota_handle *h)
+ {
+ 	struct v2_disk_dqinfo ddqinfo;
++	struct v2_mem_dqinfo *info;
++	__u64 filesize;
+ 
+ 	h->qh_info.u.v2_mdqi.dqi_qtree.dqi_entry_size =
+ 		sizeof(struct v2r1_disk_dqblk);
+@@ -185,6 +187,32 @@ static int v2_init_io(struct quota_handl
+ 			 sizeof(ddqinfo)) != sizeof(ddqinfo))
+ 		return -1;
+ 	v2_disk2memdqinfo(&h->qh_info, &ddqinfo);
++
++	/* Check to make sure quota file info is sane */
++	info = &h->qh_info.u.v2_mdqi;
++	if (ext2fs_file_get_lsize(h->qh_qf.e2_file, &filesize))
++		return -1;
++	if ((filesize > (1U << 31)) ||
++	    (info->dqi_qtree.dqi_blocks >
++	     (filesize + QT_BLKSIZE - 1) >> QT_BLKSIZE_BITS)) {
++		log_err("Quota inode %u corrupted: file size %llu; "
++			"dqi_blocks %u", h->qh_qf.ino,
++			filesize, info->dqi_qtree.dqi_blocks);
++		return -1;
++	}
++	if (info->dqi_qtree.dqi_free_blk >= info->dqi_qtree.dqi_blocks) {
++		log_err("Quota inode %u corrupted: free_blk %u; dqi_blocks %u",
++			h->qh_qf.ino, info->dqi_qtree.dqi_free_blk,
++			info->dqi_qtree.dqi_blocks);
++		return -1;
++	}
++	if (info->dqi_qtree.dqi_free_entry >= info->dqi_qtree.dqi_blocks) {
++		log_err("Quota inode %u corrupted: free_entry %u; "
++			"dqi_blocks %u", h->qh_qf.ino,
++			info->dqi_qtree.dqi_free_entry,
++			info->dqi_qtree.dqi_blocks);
++		return -1;
++	}
+ 	return 0;
+ }
+