An inode containing the value for an extended attribute (aka an
ea_in_inode) must not have the INLINE_DATA flag and must have the
EA_INODE flag set. Enforcing this prevents e2fsck and debugfs crashes
caused by a maliciously crafted file system containing an inode which
has both the EA_INODE and INLINE_DATA flags set, and where that inode
has an extended attribute whose e_value_inum points to itself.
Reported-by: Wen Xu <wen.xu@xxxxxxxxxx>
Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
---
e2fsck/pass1.c | 1 +
lib/ext2fs/ext2_err.et.in | 3 +++
lib/ext2fs/ext_attr.c | 8 +++++++-
3 files changed, 11 insertions(+), 1 deletion(-)
diff --git a/e2fsck/pass1.c b/e2fsck/pass1.c
index fccd8816a..69b3f09e7 100644
--- a/e2fsck/pass1.c
+++ b/e2fsck/pass1.c
@@ -1542,6 +1542,7 @@ void e2fsck_pass1(e2fsck_t ctx)
case EXT2_ET_NO_INLINE_DATA:
case EXT2_ET_EXT_ATTR_CSUM_INVALID:
case EXT2_ET_EA_BAD_VALUE_OFFSET:
+ case EXT2_ET_EA_INODE_CORRUPTED:
/* broken EA or no system.data EA; truncate */
if (fix_problem(ctx, PR_1_INLINE_DATA_NO_ATTR,
&pctx)) {
diff --git a/lib/ext2fs/ext2_err.et.in b/lib/ext2fs/ext2_err.et.in
index ac96964d9..16abd23d8 100644
--- a/lib/ext2fs/ext2_err.et.in
+++ b/lib/ext2fs/ext2_err.et.in
@@ -542,4 +542,7 @@ ec EXT2_ET_CORRUPT_JOURNAL_SB,
ec EXT2_ET_INODE_CORRUPTED,
"Inode is corrupted"
+ec EXT2_ET_EA_INODE_CORRUPTED,
+ "Inode containing extended attribute value is corrupted"
+
end
diff --git a/lib/ext2fs/ext_attr.c b/lib/ext2fs/ext_attr.c
index 89c5f2cb6..81b067ad5 100644
--- a/lib/ext2fs/ext_attr.c
+++ b/lib/ext2fs/ext_attr.c
@@ -903,6 +903,7 @@ static errcode_t read_xattrs_from_buffer(struct ext2_xattr_handle *handle,
memcpy(x->value, value_start + entry->e_value_offs,
entry->e_value_size);
} else {
+ struct ext2_inode *ea_inode;
ext2_file_t ea_file;
if (entry->e_value_offs != 0)
@@ -920,7 +921,12 @@ static errcode_t read_xattrs_from_buffer(struct ext2_xattr_handle *handle,
if (err)
return err;
- if (ext2fs_file_get_size(ea_file) !=
+ ea_inode = ext2fs_file_get_inode(ea_file);
+ if ((ea_inode->i_flags & EXT4_INLINE_DATA_FL) ||
+ !(ea_inode->i_flags & EXT4_EA_INODE_FL) ||
+ ea_inode->i_links_count == 0)
+ err = EXT2_ET_EA_INODE_CORRUPTED;
+ else if (ext2fs_file_get_size(ea_file) !=
entry->e_value_size)
err = EXT2_ET_EA_BAD_VALUE_SIZE;
else
--
2.16.1.72.g5be1f00a9a
