In the Linux kernel, the following vulnerability has been resolved:
ext4: make sure the first directory block is not a hole
The syzbot constructs a directory that has no dirblock but is non-inline,
i.e. the first directory block is a hole. And no errors are reported when
creating files in this directory in the following flow.
ext4_mknod
...
ext4_add_entry
// Read block 0
ext4_read_dirblock(dir, block, DIRENT)
bh = ext4_bread(NULL, inode, block, 0)
if (!bh && (type == INDEX || type == DIRENT_HTREE))
// The first directory block is a hole
// But type == DIRENT, so no error is reported.
After that, we get a directory block without ‘.’ and ‘…’ but with a valid
dentry. This may cause some code that relies on dot or dotdot (such as
make_indexed_dir()) to crash.
Therefore when ext4_read_dirblock() finds that the first directory block
is a hole report that the filesystem is corrupted and return an error to
avoid loading corrupted data from disk causing something bad.
[
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "unaffected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"fs/ext4/namei.c"
],
"versions": [
{
"version": "3a17ca864baf",
"lessThan": "d81d7e347d1f",
"status": "affected",
"versionType": "git"
},
{
"version": "4e19d6b65fb4",
"lessThan": "e02f9941e8c0",
"status": "affected",
"versionType": "git"
},
{
"version": "4e19d6b65fb4",
"lessThan": "de2a011a13a4",
"status": "affected",
"versionType": "git"
},
{
"version": "4e19d6b65fb4",
"lessThan": "9771e3d8365a",
"status": "affected",
"versionType": "git"
},
{
"version": "4e19d6b65fb4",
"lessThan": "b609753cbbd3",
"status": "affected",
"versionType": "git"
},
{
"version": "4e19d6b65fb4",
"lessThan": "c3893d9de8ee",
"status": "affected",
"versionType": "git"
},
{
"version": "4e19d6b65fb4",
"lessThan": "299bc6ffa57e",
"status": "affected",
"versionType": "git"
},
{
"version": "4e19d6b65fb4",
"lessThan": "f9ca51596bbf",
"status": "affected",
"versionType": "git"
}
]
},
{
"product": "Linux",
"vendor": "Linux",
"defaultStatus": "affected",
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"programFiles": [
"fs/ext4/namei.c"
],
"versions": [
{
"version": "5.3",
"status": "affected"
},
{
"version": "0",
"lessThan": "5.3",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "4.19.320",
"lessThanOrEqual": "4.19.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.4.282",
"lessThanOrEqual": "5.4.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.10.224",
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "5.15.165",
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.1.103",
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.6.44",
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.10.3",
"lessThanOrEqual": "6.10.*",
"status": "unaffected",
"versionType": "custom"
},
{
"version": "6.11",
"lessThanOrEqual": "*",
"status": "unaffected",
"versionType": "original_commit_for_fix"
}
]
}
]
git.kernel.org/stable/c/299bc6ffa57e04e74c6cce866d6c0741fb4897a1
git.kernel.org/stable/c/9771e3d8365ae1dd5e8846a204cb9af14e3e656a
git.kernel.org/stable/c/b609753cbbd38f8c0affd4956c0af178348523ac
git.kernel.org/stable/c/c3893d9de8ee153baac56d127d844103488133b5
git.kernel.org/stable/c/d81d7e347d1f1f48a5634607d39eb90c161c8afe
git.kernel.org/stable/c/de2a011a13a46468a6e8259db58b1b62071fe136
git.kernel.org/stable/c/e02f9941e8c011aa3eafa799def6a134ce06bcfa
git.kernel.org/stable/c/f9ca51596bbfd0f9c386dd1c613c394c78d9e5e6