CVE-2021-47636 | 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->a
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 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 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].
- 🔗 git.kernel.org/stable/c/5343575aa11c5d7044107d59d43f84ae…
- 🔗 git.kernel.org/stable/c/b80ccbec0e4804436c382d7dd60e943c…
- 🔗 git.kernel.org/stable/c/07a209fadee7b53b46858538e1177597…
- 🔗 git.kernel.org/stable/c/a7054aaf1909cf40489c0ec1b728fdcf…
- 🔗 git.kernel.org/stable/c/e09fa5318d51f522e1af4fbaf8f74999…
- 🔗 git.kernel.org/stable/c/3b7fb89135a20587d57f8877c02e2500…
- 🔗 git.kernel.org/stable/c/4f2262a334641e05f645364d5ade1f56…
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CVE-2021-47636 | 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->a
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(
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