CVE-2026-63815

*** Pendiente de traducción *** In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> f2fs: bound i_inline_xattr_size for non-inline-xattr inodes<br /> <br /> When the flexible_inline_xattr feature is enabled, do_read_inode() loads<br /> the on-disk i_inline_xattr_size unconditionally:<br /> <br /> if (f2fs_sb_has_flexible_inline_xattr(sbi))<br /> fi-&gt;i_inline_xattr_size = le16_to_cpu(ri-&gt;i_inline_xattr_size);<br /> <br /> but sanity_check_inode() only range-checks it when the inode also has the<br /> FI_INLINE_XATTR flag set. An inode that carries an inline dentry or inline<br /> data but not FI_INLINE_XATTR -- the normal layout for an inline<br /> directory -- therefore keeps a fully attacker-controlled<br /> i_inline_xattr_size from a crafted image.<br /> <br /> get_inline_xattr_addrs() returns that value with no flag gating, so it<br /> feeds the inode geometry:<br /> <br /> MAX_INLINE_DATA() = 4 * (CUR_ADDRS_PER_INODE - i_inline_xattr_size - 1)<br /> NR_INLINE_DENTRY() = MAX_INLINE_DATA() * BITS_PER_BYTE / (...)<br /> addrs_per_page() = CUR_ADDRS_PER_INODE - i_inline_xattr_size<br /> <br /> A large i_inline_xattr_size drives MAX_INLINE_DATA() and NR_INLINE_DENTRY()<br /> negative, so make_dentry_ptr_inline() sets d-&gt;max (int) to a negative<br /> value. The inline directory walk then compares an unsigned long bit_pos<br /> against that negative d-&gt;max, which is promoted to a huge unsigned bound,<br /> and reads far past the inline area:<br /> <br /> while (bit_pos max) /* fs/f2fs/dir.c */<br /> ... test_bit_le(bit_pos, d-&gt;bitmap) / d-&gt;dentry[bit_pos] ...<br /> <br /> Mounting a crafted image and reading such a directory triggers an<br /> out-of-bounds read in f2fs_fill_dentries(); the same underflow also<br /> corrupts ADDRS_PER_INODE for regular files.<br /> <br /> Validate i_inline_xattr_size against MAX_INLINE_XATTR_SIZE whenever the<br /> flexible_inline_xattr feature is enabled -- i.e. whenever the value is<br /> loaded from disk and consumed -- and keep the lower MIN_INLINE_XATTR_SIZE<br /> bound gated on inodes that actually carry an inline xattr, so legitimate<br /> inodes with i_inline_xattr_size == 0 are still accepted.