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| author | Eric Biggers <ebiggers@google.com> | 2018-03-29 21:31:42 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-04-24 10:36:30 +0300 |
| commit | a57eb14b740e6175aff8b8941bec628403992dfa (patch) | |
| tree | 7c64b6831765a8022a8513e7a388091fafa0edd5 /fs | |
| parent | 5058b70d2118ee0304a2f3124946c4089b06abde (diff) | |
| download | linux-a57eb14b740e6175aff8b8941bec628403992dfa.tar.xz | |
ext4: limit xattr size to INT_MAX
commit ce3fd194fcc6fbdc00ce095a852f22df97baa401 upstream.
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")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -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 218a7ba57819..5d0f5ba5c6f5 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -194,10 +194,13 @@ 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; /* |