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authorTheodore Ts'o <tytso@mit.edu>2018-06-13 00:23:11 -0400
committerTheodore Ts'o <tytso@mit.edu>2018-06-13 00:23:11 -0400
commit5369a762c882c0b6e9599e4ebbb3a9ba9eee7e2d (patch)
treefe0425a2ac97acce9b8d68b051edad388813dc59 /fs/ext4
parent327eaf738ff97d19491362e30497954105d60414 (diff)
downloadlinux-5369a762c882c0b6e9599e4ebbb3a9ba9eee7e2d.tar.bz2
ext4: add corruption check in ext4_xattr_set_entry()
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
Diffstat (limited to 'fs/ext4')
-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)