In the Linux kernel, the following vulnerability has been resolved:
f2fs: bound i_inline_xattr_size for non-inline-xattr inodes
When the flexible_inline_xattr feature is enabled, do_read_inode() loads
the on-disk i_inline_xattr_size unconditionally:
if (f2fs_sb_has_flexible_inline_xattr(sbi))
fi->i_inline_xattr_size = le16_to_cpu(ri->i_inline_xattr_size);
but sanity_check_inode() only range-checks it when the inode also has the
FI_INLINE_XATTR flag set. An inode that carries an inline dentry or inline
data but not FI_INLINE_XATTR -- the normal layout for an inline
directory -- therefore keeps a fully attacker-controlled
i_inline_xattr_size from a crafted image.
get_inline_xattr_addrs() returns that value with no flag gating, so it
feeds the inode geometry:
MAX_INLINE_DATA() = 4 * (CUR_ADDRS_PER_INODE - i_inline_xattr_size - 1)
NR_INLINE_DENTRY() = MAX_INLINE_DATA() * BITS_PER_BYTE / (...)
addrs_per_page() = CUR_ADDRS_PER_INODE - i_inline_xattr_size
A large i_inline_xattr_size drives MAX_INLINE_DATA() and NR_INLINE_DENTRY()
negative, so make_dentry_ptr_inline() sets d->max (int) to a negative
value. The inline directory walk then compares an unsigned long bit_pos
against that negative d->max, which is promoted to a huge unsigned bound,
and reads far past the inline area:
while (bit_pos < d->max) /* fs/f2fs/dir.c */
... test_bit_le(bit_pos, d->bitmap) / d->dentry[bit_pos] ...
Mounting a crafted image and reading such a directory triggers an
out-of-bounds read in f2fs_fill_dentries(); the same underflow also
corrupts ADDRS_PER_INODE for regular files.
Validate i_inline_xattr_size against MAX_INLINE_XATTR_SIZE whenever the
flexible_inline_xattr feature is enabled -- i.e. whenever the value is
loaded from disk and consumed -- and keep the lower MIN_INLINE_XATTR_SIZE
bound gated on inodes that actually carry an inline xattr, so legitimate
inodes with i_inline_xattr_size == 0 are still accepted.
References
Configurations
Configuration 1 (hide)
|
History
10 Nov 2026, 20:43
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| CWE | CWE-125 | |
| First Time |
Linux linux Kernel
Linux |
|
| References | () https://git.kernel.org/stable/c/16bc237ce3c483b75575abea53cfb639745311ed - Patch | |
| References | () https://git.kernel.org/stable/c/2a9f9791653ba5ed3fb45bbffa8d63a7cd5cf706 - Patch | |
| References | () https://git.kernel.org/stable/c/378acf3cf19b6af6cba55e8dd1154c4e1504bae8 - Patch | |
| References | () https://git.kernel.org/stable/c/3c8d6b4093aea40a20596f452289e7c22d84e6d5 - Patch | |
| References | () https://git.kernel.org/stable/c/4ce2d52f680c1d8bfdad7cce05b815ea7ca9790d - Patch | |
| References | () https://git.kernel.org/stable/c/76e1a05cf6d4051931d7fa4ead51a05786a62918 - Patch | |
| References | () https://git.kernel.org/stable/c/a08ee30dcbeff6b97df75c38c2589603ddde53a6 - Patch | |
| References | () https://git.kernel.org/stable/c/c3e05522daae4e7348a1ea81eeb321d25aa0fd3b - Patch |
Information
Published : 2026-07-19 12:16
Updated : 2026-11-10 20:43
NVD link : CVE-2026-63815
Mitre link : CVE-2026-63815
CVE.ORG link : CVE-2026-63815
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-125
Out-of-bounds Read