CVE-2021-47636
Feb. 26, 2025, 6:37 a.m.
None
No Score
Description
In the Linux kernel, the following vulnerability has been resolved:
ubifs: Fix read out-of-bounds in ubifs_wbuf_write_nolock()
Function ubifs_wbuf_write_nolock() may access buf out of bounds in
following process:
ubifs_wbuf_write_nolock():
aligned_len = ALIGN(len, 8); // Assume len = 4089, aligned_len = 4096
if (aligned_len <= wbuf->avail) ... // Not satisfy
if (wbuf->used) {
ubifs_leb_write() // Fill some data in avail wbuf
len -= wbuf->avail; // len is still not 8-bytes aligned
aligned_len -= wbuf->avail;
}
n = aligned_len >> c->max_write_shift;
if (n) {
n <<= c->max_write_shift;
err = ubifs_leb_write(c, wbuf->lnum, buf + written,
wbuf->offs, n);
// n > len, read out of bounds less than 8(n-len) bytes
}
, which can be catched by KASAN:
=========================================================
BUG: KASAN: slab-out-of-bounds in ecc_sw_hamming_calculate+0x1dc/0x7d0
Read of size 4 at addr ffff888105594ff8 by task kworker/u8:4/128
Workqueue: writeback wb_workfn (flush-ubifs_0_0)
Call Trace:
kasan_report.cold+0x81/0x165
nand_write_page_swecc+0xa9/0x160
ubifs_leb_write+0xf2/0x1b0 [ubifs]
ubifs_wbuf_write_nolock+0x421/0x12c0 [ubifs]
write_head+0xdc/0x1c0 [ubifs]
ubifs_jnl_write_inode+0x627/0x960 [ubifs]
wb_workfn+0x8af/0xb80
Function ubifs_wbuf_write_nolock() accepts that parameter 'len' is not 8
bytes aligned, the 'len' represents the true length of buf (which is
allocated in 'ubifs_jnl_xxx', eg. ubifs_jnl_write_inode), so
ubifs_wbuf_write_nolock() must handle the length read from 'buf' carefully
to write leb safely.
Fetch a reproducer in [Link].
Product(s) Impacted
Product | Versions |
---|---|
Linux Kernel (ubifs module) |
|
Weaknesses
References
Tags
Date
- Published: Feb. 26, 2025, 6:37 a.m.
- Last Modified: Feb. 26, 2025, 6:37 a.m.
Status : Awaiting Analysis
CVE has been recently published to the CVE List and has been received by the NVD.
More infoSource
416baaa9-dc9f-4396-8d5f-8c081fb06d67
*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.