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.
Edward Adam Davis
authored
The dns_resolver_preparse() function has a check on the size of the
payload for the basic header of the binary-style payload, but is missing
a check for the size of the V1 server-list payload header after
determining that's what we've been given.
Fix this by getting rid of the the pointer to the basic header and just
assuming that we have a V1 server-list payload and moving the V1 server
list pointer inside the if-statement. Dealing with other types and
versions can be left for when such have been defined.
This can be tested by doing the following with KASAN enabled:
echo -n -e '\x0\x0\x1\x2' | keyctl padd dns_resolver foo @p
and produces an oops like the following:
BUG: KASAN: slab-out-of-bounds in dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127
Read of size 1 at addr ffff888028894084 by task syz-executor265/5069
...
Call Trace:
dns_resolver_preparse+0xc9f/0xd60 net/dns_resolver/dns_key.c:127
__key_create_or_update+0x453/0xdf0 security/keys/key.c:842
key_create_or_update+0x42/0x50 security/keys/key.c:1007
__do_sys_add_key+0x29c/0x450 security/keys/keyctl.c:134
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0x40/0x110 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x62/0x6a
This patch was originally by Edward Adam Davis, but was modified by
Linus.
Fixes: b946001d3bb1 ("keys, dns: Allow key types (eg. DNS) to be reclaimed immediately on expiry")
Reported-and-tested-by: 
<syzbot+94bbb75204a05da3d89f@syzkaller.appspotmail.com>
Link: https://lore.kernel.org/r/0000000000009b39bc060c73e209@google.com/
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Edward Adam Davis <eadavis@qq.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: David Howells <dhowells@redhat.com>
Cc: Edward Adam Davis <eadavis@qq.com>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Jeffrey E Altman <jaltman@auristor.com>
Cc: Wang Lei <wang840925@gmail.com>
Cc: Jeff Layton <jlayton@redhat.com>
Cc: Steve French <sfrench@us.ibm.com>
Cc: Marc Dionne <marc.dionne@auristor.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>