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cefa91b233
Given a sufficiently large number of actions, while copying and
reserving memory for a new action of a new flow, if next_offset is
greater than MAX_ACTIONS_BUFSIZE, the function reserve_sfa_size() does
not return -EMSGSIZE as expected, but it allocates MAX_ACTIONS_BUFSIZE
bytes increasing actions_len by req_size. This can then lead to an OOB
write access, especially when further actions need to be copied.
Fix it by rearranging the flow action size check.
KASAN splat below:
==================================================================
BUG: KASAN: slab-out-of-bounds in reserve_sfa_size+0x1ba/0x380 [openvswitch]
Write of size 65360 at addr ffff888147e4001c by task handler15/836
CPU: 1 PID: 836 Comm: handler15 Not tainted 5.18.0-rc1+ #27
...
Call Trace:
<TASK>
dump_stack_lvl+0x45/0x5a
print_report.cold+0x5e/0x5db
? __lock_text_start+0x8/0x8
? reserve_sfa_size+0x1ba/0x380 [openvswitch]
kasan_report+0xb5/0x130
? reserve_sfa_size+0x1ba/0x380 [openvswitch]
kasan_check_range+0xf5/0x1d0
memcpy+0x39/0x60
reserve_sfa_size+0x1ba/0x380 [openvswitch]
__add_action+0x24/0x120 [openvswitch]
ovs_nla_add_action+0xe/0x20 [openvswitch]
ovs_ct_copy_action+0x29d/0x1130 [openvswitch]
? __kernel_text_address+0xe/0x30
? unwind_get_return_address+0x56/0xa0
? create_prof_cpu_mask+0x20/0x20
? ovs_ct_verify+0xf0/0xf0 [openvswitch]
? prep_compound_page+0x198/0x2a0
? __kasan_check_byte+0x10/0x40
? kasan_unpoison+0x40/0x70
? ksize+0x44/0x60
? reserve_sfa_size+0x75/0x380 [openvswitch]
__ovs_nla_copy_actions+0xc26/0x2070 [openvswitch]
? __zone_watermark_ok+0x420/0x420
? validate_set.constprop.0+0xc90/0xc90 [openvswitch]
? __alloc_pages+0x1a9/0x3e0
? __alloc_pages_slowpath.constprop.0+0x1da0/0x1da0
? unwind_next_frame+0x991/0x1e40
? __mod_node_page_state+0x99/0x120
? __mod_lruvec_page_state+0x2e3/0x470
? __kasan_kmalloc_large+0x90/0xe0
ovs_nla_copy_actions+0x1b4/0x2c0 [openvswitch]
ovs_flow_cmd_new+0x3cd/0xb10 [openvswitch]
...
Cc: stable@vger.kernel.org
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| 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 | ||
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.