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| author | Eric Biggers <ebiggers@google.com> | 2018-03-29 14:31:42 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2018-03-29 14:31:42 -0400 |
| commit | ce3fd194fcc6fbdc00ce095a852f22df97baa401 (patch) | |
| tree | 253d8a212f3e27bf2fc56e8176a4b44f8e15c944 /fs/ext4 | |
| parent | 7dac4a1726a9c64a517d595c40e95e2d0d135f6f (diff) | |
| download | linux-stable-ce3fd194fcc6fbdc00ce095a852f22df97baa401.tar.gz linux-stable-ce3fd194fcc6fbdc00ce095a852f22df97baa401.tar.bz2 linux-stable-ce3fd194fcc6fbdc00ce095a852f22df97baa401.zip | |
ext4: limit xattr size to INT_MAX
ext4 isn't validating the sizes of xattrs where the value of the xattr
is stored in an external inode. This is problematic because
->e_value_size is a u32, but ext4_xattr_get() returns an int. A very
large size is misinterpreted as an error code, which ext4_get_acl()
translates into a bogus ERR_PTR() for which IS_ERR() returns false,
causing a crash.
Fix this by validating that all xattrs are <= INT_MAX bytes.
This issue has been assigned CVE-2018-1095.
https://bugzilla.kernel.org/show_bug.cgi?id=199185
https://bugzilla.redhat.com/show_bug.cgi?id=1560793
Reported-by: Wen Xu <wen.xu@gatech.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Fixes: e50e5129f384 ("ext4: xattr-in-inode support")
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/xattr.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index 63656dbafdc4..2077d87b09f2 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -195,10 +195,13 @@ ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end, /* Check the values */ while (!IS_LAST_ENTRY(entry)) { - if (entry->e_value_size != 0 && - entry->e_value_inum == 0) { + u32 size = le32_to_cpu(entry->e_value_size); + + if (size > INT_MAX) + return -EFSCORRUPTED; + + if (size != 0 && entry->e_value_inum == 0) { u16 offs = le16_to_cpu(entry->e_value_offs); - u32 size = le32_to_cpu(entry->e_value_size); void *value; /* |