d41a3effbb
If a request_key authentication token key gets revoked, there's a window in
which request_key_auth_describe() can see it with a NULL payload - but it
makes no check for this and something like the following oops may occur:
BUG: Kernel NULL pointer dereference at 0x00000038
Faulting instruction address: 0xc0000000004ddf30
Oops: Kernel access of bad area, sig: 11 [#1]
...
NIP [...] request_key_auth_describe+0x90/0xd0
LR [...] request_key_auth_describe+0x54/0xd0
Call Trace:
[...] request_key_auth_describe+0x54/0xd0 (unreliable)
[...] proc_keys_show+0x308/0x4c0
[...] seq_read+0x3d0/0x540
[...] proc_reg_read+0x90/0x110
[...] __vfs_read+0x3c/0x70
[...] vfs_read+0xb4/0x1b0
[...] ksys_read+0x7c/0x130
[...] system_call+0x5c/0x70
Fix this by checking for a NULL pointer when describing such a key.
Also make the read routine check for a NULL pointer to be on the safe side.
[DH: Modified to not take already-held rcu lock and modified to also check
in the read routine]
Fixes:
|
||
---|---|---|
Documentation | ||
LICENSES | ||
arch | ||
block | ||
certs | ||
crypto | ||
drivers | ||
fs | ||
include | ||
init | ||
ipc | ||
kernel | ||
lib | ||
mm | ||
net | ||
samples | ||
scripts | ||
security | ||
sound | ||
tools | ||
usr | ||
virt | ||
.clang-format | ||
.cocciconfig | ||
.get_maintainer.ignore | ||
.gitattributes | ||
.gitignore | ||
.mailmap | ||
COPYING | ||
CREDITS | ||
Kbuild | ||
Kconfig | ||
MAINTAINERS | ||
Makefile | ||
README |
README
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.