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Martin KaFai Lau 091a9dc7a5 bpf: Stop caching subprog index in the bpf_pseudo_func insn
commit 3990ed4c42 upstream.

This patch is to fix an out-of-bound access issue when jit-ing the
bpf_pseudo_func insn (i.e. ld_imm64 with src_reg == BPF_PSEUDO_FUNC)

In jit_subprog(), it currently reuses the subprog index cached in
insn[1].imm.  This subprog index is an index into a few array related
to subprogs.  For example, in jit_subprog(), it is an index to the newly
allocated 'struct bpf_prog **func' array.

The subprog index was cached in insn[1].imm after add_subprog().  However,
this could become outdated (and too big in this case) if some subprogs
are completely removed during dead code elimination (in
adjust_subprog_starts_after_remove).  The cached index in insn[1].imm
is not updated accordingly and causing out-of-bound issue in the later
jit_subprog().

Unlike bpf_pseudo_'func' insn, the current bpf_pseudo_'call' insn
is handling the DCE properly by calling find_subprog(insn->imm) to
figure out the index instead of caching the subprog index.
The existing bpf_adj_branches() will adjust the insn->imm
whenever insn is added or removed.

Instead of having two ways handling subprog index,
this patch is to make bpf_pseudo_func works more like
bpf_pseudo_call.

First change is to stop caching the subprog index result
in insn[1].imm after add_subprog().  The verification
process will use find_subprog(insn->imm) to figure
out the subprog index.

Second change is in bpf_adj_branches() and have it to
adjust the insn->imm for the bpf_pseudo_func insn also
whenever insn is added or removed.

Third change is in jit_subprog().  Like the bpf_pseudo_call handling,
bpf_pseudo_func temporarily stores the find_subprog() result
in insn->off.  It is fine because the prog's insn has been finalized
at this point.  insn->off will be reset back to 0 later to avoid
confusing the userspace prog dump tool.

Fixes: 69c087ba62 ("bpf: Add bpf_for_each_map_elem() helper")
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211106014014.651018-1-kafai@fb.com
Cc: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-19 17:51:01 +08:00
arch xen/arm: Fix race in RB-tree based P2M accounting 2023-04-19 17:50:56 +08:00
block block: Fix handling of offline queues in blk_mq_alloc_request_hctx() 2023-04-19 17:50:34 +08:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2023-04-19 17:50:34 +08:00
crypto crypto: memneq - move into lib/ 2023-04-19 17:50:35 +08:00
Documentation docs: update mapping documentation 2023-04-19 17:50:49 +08:00
drivers mt76: mt7921: fix a possible race enabling/disabling runtime-pm 2023-04-19 17:51:01 +08:00
fs btrfs: fix deadlock between chunk allocation and chunk btree modifications 2023-04-19 17:51:00 +08:00
include bpf: Stop caching subprog index in the bpf_pseudo_func insn 2023-04-19 17:51:01 +08:00
init Kconfig: Add option for asm goto w/ tied outputs to workaround clang-13 bug 2023-04-19 17:50:04 +08:00
ipc ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() 2023-04-19 17:49:52 +08:00
kernel bpf: Stop caching subprog index in the bpf_pseudo_func insn 2023-04-19 17:51:01 +08:00
lib crypto: memneq - move into lib/ 2023-04-19 17:50:35 +08:00
LICENSES LICENSES/dual/CC-BY-4.0: Git rid of "smart quotes" 2021-07-15 06:31:24 -06:00
mm mm/filemap: fix UAF in find_lock_entries 2023-04-19 17:50:57 +08:00
net netfilter: nf_tables: stricter validation of element data 2023-04-19 17:50:59 +08:00
samples samples/landlock: Format with clang-format 2023-04-19 17:50:01 +08:00
scripts modpost: fix section mismatch check for exported init/exit sections 2023-04-19 17:50:47 +08:00
security fs: support mapped mounts of mapped filesystems 2023-04-19 17:50:49 +08:00
sound ALSA: cs46xx: Fix missing snd_card_free() call at probe error 2023-04-19 17:50:58 +08:00
tools Revert "selftests/bpf: Add test for bpf_timer overwriting crash" 2023-04-19 17:50:57 +08:00
usr usr/include/Makefile: add linux/nfc.h to the compile-test coverage 2023-04-19 17:44:58 +08:00
virt KVM: avoid NULL pointer dereference in kvm_dirty_ring_push 2023-04-19 17:47:52 +08:00
.clang-format clang-format: Update with the latest for_each macro list 2021-05-12 23:32:39 +02:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: add Andrej Shadura 2021-10-18 20:22:03 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Move Daniel Drake to credits 2021-09-21 08:34:58 +03:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS Input: goodix - add a goodix.h header file 2023-04-19 17:50:59 +08:00
Makefile Linux 5.15.53 2023-04-19 17:50:57 +08:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

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.