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authorTheodore Ts'o <tytso@mit.edu>2018-06-13 00:23:11 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-07-11 16:31:28 +0200
commite4130b9612095a6db9bafb90634fbd579b77d893 (patch)
treee6e6e577daaf5f1a13a3e3eae6bea1085b1795b0
parentf869e0b631a6a7befe595dbad0b2e3662c6d1a99 (diff)
ext4: add corruption check in ext4_xattr_set_entry()
commit 5369a762c882c0b6e9599e4ebbb3a9ba9eee7e2d upstream. In theory this should have been caught earlier when the xattr list was verified, but in case it got missed, it's simple enough to add check to make sure we don't overrun the xattr buffer. This addresses CVE-2018-10879. https://bugzilla.kernel.org/show_bug.cgi?id=200001 Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Andreas Dilger <adilger@dilger.ca> Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/ext4/xattr.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index fc4ced59c565..230ba79715f6 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -1560,7 +1560,7 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
handle_t *handle, struct inode *inode,
bool is_block)
{
- struct ext4_xattr_entry *last;
+ struct ext4_xattr_entry *last, *next;
struct ext4_xattr_entry *here = s->here;
size_t min_offs = s->end - s->base, name_len = strlen(i->name);
int in_inode = i->in_inode;
@@ -1595,7 +1595,13 @@ static int ext4_xattr_set_entry(struct ext4_xattr_info *i,
/* Compute min_offs and last. */
last = s->first;
- for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) {
+ for (; !IS_LAST_ENTRY(last); last = next) {
+ next = EXT4_XATTR_NEXT(last);
+ if ((void *)next >= s->end) {
+ EXT4_ERROR_INODE(inode, "corrupted xattr entries");
+ ret = -EFSCORRUPTED;
+ goto out;
+ }
if (!last->e_value_inum && last->e_value_size) {
size_t offs = le16_to_cpu(last->e_value_offs);
if (offs < min_offs)